Modification of EWS/WT1 functional properties by phosphorylation.

Kim J, Lee JM, Branton PE, Pelletier J

Department of Biochemistry, McGill University, McIntyre Medical Sciences Building, 3655 Drummond Street, Montreal, Quebec H3G 1Y6, Canada.

In many human cancers, tumor-specific chromosomal rearrangements are known to create chimeric products with the ability to transform cells. The EWS/WT1 protein is such a fusion product, resulting from a t(11;22) chromosomal translocation in desmoplastic small round cell tumors, where 265 aa from the EWS amino terminus are fused to the DNA binding domain of the WT1 tumor suppressor gene. Herein, we find that EWS/WT1 is phosphorylated in vivo on serine and tyrosine residues and that this affects DNA binding and homodimerization. We also show that EWS/WT1 can interact with, and is a substrate for, modification on tyrosine residues by c-Abl. Tyrosine phosphorylation of EWS/WT1 by c-Abl negatively regulates its DNA binding properties. These results indicate that the biological activity of EWS/WT1 is closely linked to its phosphorylation status.

2: Med Pediatr Oncol 1999 Dec;33(6):530-5

Clinically critical impact of molecular genetic studies in pediatric solid tumors.

Kushner BH, LaQuaglia MP, Cheung NK, Kramer K, Hamelin AC, Gerald WL, Ladanyi M

BACKGROUND: Standard cytogenetic techniques are time-consuming and often not informative with solid tumors. In contrast, the reverse transcriptase-polymerase chain reaction (RT-PCR) is a readily available technique that can rapidly detect tumor-specific chromosomal rearrangements, even in small biopsy specimens. We present cases depicting the importance of including molecular diagnostic studies in the routine evaluation of pediatric solid tumors. PROCEDURE: We used RT-PCR to detect chimeric transcripts specific for major pediatric solid tumors, including peripheral primitive neuroectodermal tumor (pPNET), alveolar rhabdomyosarcoma (ARMS), and desmoplastic small round-cell tumor (DSRCT). We reviewed six recent cases in which the initial diagnosis was changed by the results of RT-PCR. RESULTS: Highly unusual or nonspecific clinical and/or histopathologic findings led to the initial diagnoses of neuroblastoma in three patients and DSRCT, leukemia, and carcinoma in one patient each. The final diagnoses after RT-PCR studies were pPNET in three patients, ARMS in two patients, and DSRCT in one patient. RT-PCR results led to early corrections in the diagnosis in two patients, but four patients received treatment not considered optimal for the neoplasms ultimately diagnosed, including three who, despite presenting with localized tumors that have a >70% cure rate with standard therapy, have died or are dying of disease. CONCLUSIONS: Molecular genetic studies on solid tumors can clarify the diagnosis in seemingly straightforward as well as in overtly problematic cases. These diagnostic distinctions are now critical as disease-specific and risk-directed therapies have emerged. Copyright 1999 Wiley-Liss, Inc.

3: Eur J Surg Oncol 1999 Dec;25(6):633-4

Desmoplastic small round cell tumour of the pleura: a case report with further cytogenetic and ultrastructural evidence of ‘mesothelioblastemic’ origin.

Sapi Z, Szentirmay Z, Orosz Z

Department of Pathology, St. John’s Hospital, Budapest, Hungary.

A typical case of desmoplastic small round cell tumour of the pleura in a 25-year-old man is described. In addition to the typical histological and immunohistological findings, the EWS-WT1 fusion product was also observed. Ultrastructurally, some tumour cells displayed intracytoplasmic neolumina, with short microvilli characteristic of submesothelial cells. These findings support the theory of a splanchnopleuric intraembryonic mesodermal, ‘mesothelioblastemic’ origin, both morphologically and cytogenetically. Copyright 1999 Harcourt Publishers Ltd.

4: Am J Surg Pathol 1999 Nov;23(11):1408-13

Primary desmoplastic small cell tumor of soft tissues and bone of the hand.

Adsay V, Cheng J, Athanasian E, Gerald W, Rosai J

Department of Pathology, Memorial Sloan-Kettering Cancer Center, New York, NY, USA.

Desmoplastic small cell tumor (DSCT) is a high-grade malignant neoplasm that shows polyphenotypic differentiation. Its almost exclusive involvement of serosal surfaces (particularly peritoneum) has led to the consideration of a putative "mesothelioblast" as the cell of origin. Although an extraserosal case involving the brain (presumably arising from the dura) has been reported, to date no case primary in the bone or soft tissues has been documented. The authors describe a 34-year-old man who presented with a 3-year history of pain in the right hand and a recently noted mass in the hypothenar area. Open biopsy followed by wide en bloc excision in combination with index ray resection was performed. Subsequently, the patient underwent ipsilateral axillary lymph node dissection. Extensive radiologic workup at the time of presentation and 12 months later revealed no tumor in the chest or abdomen. The patient was treated with an HD-CAV chemotherapy regimen (cyclophosphamide, doxorubicin, vincristine, ifosfamide, etoposide) and was free of tumor until 18 months later, at which time he developed multiple metastases in the lungs. Currently, he is alive with tumor and in poor condition. The histologic sections of the mass displayed the characteristic features of DSCT involving bone and soft tissue. Immunohistochemical stains showed positivity of the tumor cells for muscle marker (desmin), neuroendocrine markers (chromogranin, synaptophysin), and epithelial markers (keratins CAM5.2, AE1:AE3, epithelial membrane antigen). Chimeric transcripts were detected by reverse transcriptase-polymerase chain reaction, indicating the presence of EWS-WT1 gene fusion, which is characteristically associated with DSCT. Sequence analysis showed in-frame fusion of EWS exon 9 to WT1 exon 8--a variant not documented in any other case. This is a unique example of DSCT primary in bone and soft tissues, which raises interesting questions about the histogenesis of this tumor type and its relationship to other small round cell tumors. Although the "mesothelioblast" hypothesis as the origin of DSCTs is attractive, it does not account for the tumors that are located in the brain or, as in this patient, in the soft tissues and bone. In addition, this patient demonstrates a rare variant of EWS-WT1 gene fusion not described in DSCT involving serosal surfaces.

5: Med Pediatr Oncol 1999 Nov;33(5):500-3

Successful clinical response to irinotecan in desmoplastic round blue cell tumor.

Rosoff PM, Bayliff S

Division of Hematology-Oncology, Department of Pediatrics, Duke University

6: Mod Pathol 1999 Sep;12(9):849-53

Cytokeratin-negative desmoplastic small round cell tumor: a report of two cases emphasizing the utility of reverse transcriptase-polymerase chain reaction.

Trupiano JK, Machen SK, Barr FG, Goldblum JR

Department of Anatomic Pathology, The Cleveland Clinic Foundation, Ohio 44195, USA.

Desmoplastic small round cell tumor (DSRCT) is a unique, highly aggressive neoplasm that chiefly affects male adolescents and young adults. This tumor is characterized by nests of small undifferentiated cells that show immunohistochemical evidence of epithelial, mesenchymal, and neural differentiation. We report two cases of DSRCT that lacked immunohistochemical evidence of epithelial differentiation, but were found to have the fusion transcripts characteristic of this tumor. Both patients (a 41-year-old male and a 31-year-old female) presented with large intra-abdominal masses. After diagnostic biopsy, both were treated with multi-agent chemotherapy. One patient expired 18 days after diagnosis, and the other is currently alive 28 months later. Histologically, both tumors had the characteristic features of DSRCT and were composed of small round cells with hyperchromatic nuclei and scanty cytoplasm. In one of the cases, perinuclear intracytoplasmic hyaline inclusions were seen. Immunohistochemically, neither case expressed any of the epithelial markers tested, including AE1/AE3, CAM 5.2 and EMA. Both tumors were diffusely immunoreactive for desmin with a prominent globoid "dot-like" pattern of staining in one case. Both tumors stained for vimentin, neuron specific enolase, and synaptophysin, but were negative for CD99, muscle-specific actin, and myogenin. Reverse transcriptase-polymerase chain reaction revealed EWS-WT1 fusion transcripts characteristic of this neoplasm. In conclusion, we describe two cases of DSRCT that lacked immunohistochemical evidence of epithelial differentiation but had histologic and other immunohistochemical features which suggested this diagnosis. The ability to confirm the diagnosis of this rare tumor using molecular genetic techniques is particularly useful in those cases with unusual histologic or immunophenotypic features.

7: Clin Nucl Med 1999 Sep;24(9):693-4

F-18 fluorodeoxyglucose positron emission tomographic imaging in desmoplastic small round cell tumor of the abdomen.

Pickhardt PJ

8: Pediatr Dev Pathol 1998 Jul-Aug;1(4):295-9

Melanotic neuroectodermal tumor of infancy: a molecular genetic study.

Khoddami M, Squire J, Zielenska M, Thorner P

Department of Pediatric Laboratory Medicine, Hospital for Sick Children, Toronto, Ontario, Canada.

Melanotic neuroectodermal tumor of infancy is a rare but well-recognized entity in pediatric pathology. However, the relationship of this tumor to other pediatric small cell tumors with neuroectodermal features (such as neuroblastoma, Ewing sarcoma/peripheral primitive neuroectodermal tumor, and desmoplastic small round cell tumor) is undetermined. Molecular genetic studies of melanotic neuroectodermal tumor of infancy have not been reported. We studied three typical cases of melanotic neuroectodermal tumor of infancy in an attempt to link this tumor to other small cell tumors with well-characterized molecular genetic changes. Tests performed included: detection of MYCN gene amplification and deletion of 1p (all 3 cases), and presence of the t(11;22)(q24;q12) and the t(11;22)(p13;q12) translocations (2 of 3 cases). None of these tests yielded positive results. Thus, there is no genetic basis at present to link melanotic neuroectodermal tumor of infancy to neuroblastoma, Ewing sarcoma/peripheral primitive neuroectodermal tumor, or desmoplastic small round cell tumor.

9: J Clin Oncol 1999 Jan;17(1):180-90

Chemotherapy dose-intensification for pediatric patients with Ewing’s family of tumors and desmoplastic small round-cell tumors: a feasibility study at St. Jude Children’s Research Hospital.

Marina NM, Pappo AS, Parham DM, Cain AM, Rao BN, Poquette CA, Pratt CB,

Greenwald C, Meyer WH

Department of Hematology-Oncology, St. Jude Children’s Research Hospital, University of Tennessee, Memphis, USA.

PURPOSE: To evaluate the feasibility of dose-intensification for patients with Ewing’s family of tumors (EFT) and desmoplastic small round-cell tumors. PATIENTS AND METHODS: From February 1992 to June 1996, we treated 53 consecutive patients on our Ewing’s protocol. Induction comprised three cycles of ifosfamide/etoposide on days 1 to 3 and cyclophosphamide (CTX)/doxorubicin on day 5, followed by granulocyte colony-stimulating factor. Local control using surgery and/or radiotherapy started at week 9 along with vincristine/dactinomycin. Maintenance included four alternating cycles of ifosfamide/etoposide and doxorubicin/CTX, with randomization to one of two CTX dose levels to determine the feasibility of dose-intensification during maintenance. RESULTS: Patients had a median age of 13.4 years (range, 4.5 to 24.9 years); 34 patients were male and 43 patients were white. Nineteen patients presented with metastatic disease, 29 had tumors greater than 8 cm in diameter, and 26 had primary bone tumors. These patients received 155 induction cycles, 91% of which resulted in grade 4 neutropenia, 68% in febrile neutropenia, and 68% in grade 3 to 4 thrombocytopenia. During maintenance, grade 4 neutropenia and grade 3 to 4 thrombocytopenia occurred in 81% and 85% of cycles, respectively. Thirty-five patients (66%) completed all therapy, only 13 without significant delays; three developed secondary myeloid malignancies. The toxicity and time to therapy completion were similar in both CTX arms. Estimated 3-year survival and event-free survival were 72%+/-8% and 60%+/-9%, respectively. CONCLUSION: Although intensifying therapy seems feasible for 25% of patients on this study, toxicity was considerable. Therefore, the noninvestigational use of dose-intensification in patients with EFT should await assessment of its impact on disease-free survival.

Randomized controlled trial

10: J Surg Oncol 1999 Aug;71(4):269-72

Paratesticular desmoplastic small round cell tumor: case report and review of the literature.

Roganovich J, Bisogno G, Cecchetto G, D’Amore ES, Carli M

Division of Hematology/Oncology, Department of Pediatrics, University of Padova, Padova, Italy.

Desmoplastic small round cell tumor (DSRCT) is a rare neoplasm mainly affecting young males and typically located in the abdomen. Prognosis is generally very poor. We report a rare case of paratesticular DSRCT in a 17-year-old boy, presenting with an isolated left scrotal mass. The patient had an excellent outcome after complete surgical resection of the tumor and adjuvant multi-agent chemotherapy. DSRCT should be included in the differential diagnosis of small round cell tumors of the paratesticular region in adolescents and young adults. Tumor resection and chemotherapy may be beneficial for these patients. Our experience and a review of the literature suggest that DSRCT located in the paratesticular region may have a better prognosis than its more frequent abdominal counterpart. Copyright 1999 Wiley-Liss, Inc.

Review of reported cases

11: Acta Cytol 1999 Jul-Aug;43(4):641-6

Fine needle aspiration cytology of desmoplastic small round cell tumor. A case report.

Insabato L, Di Vizio D, Lambertini M, Bucci L, Pettinato G

Department of Pathology, University of Naples Federico II, Italy.

BACKGROUND: Intraabdominal desmoplastic small round cell tumor (DSRCT) is a recently recognized type of primitive sarcoma characterized by a predilection for young males, a usually very aggressive course and generally unsuccessful therapy. A primitive histologic appearance with prominent desmoplasia and striking divergent multilineage differentiation are well-described morphologic features of this tumor, along with a consistent fusion of the EWS and WT1 genes at the molecular level. The cytologic literature contains only scattered references to this type of neoplasm. Detailed information on the clinical and fine needle aspiration (FNA) biopsy and the immunocytochemical and ultrastructural findings in a patient with DSRCT is presented. CASE REPORT: A 23-year-old male had a firm abdominal mass with multiple secondary lesions of the liver. An FNA biopsy was performed under ultrasonographic guidance. CONCLUSION: FNA of the liver nodules showed cohesive groups of small cells with hyperchromatic nuclei and inconspicuous nucleoli; immunocytochemically vimentin and desmin showed characteristic perinuclear globular positivity. FNA cytology is an effective means of diagnosing deeply located lesions. The cytologic features of DSRCT need to become familiar to pathologists and must be considered in the differential diagnosis of liver metastasis.

12: Mod Pathol 1999 Jul;12(7):729-34

Desmoplastic small round-cell tumor of the paratesticular region: report of an adult case with demonstration of EWS and WT1 gene fusion using paraffin-embedded tissue.

Kawano N, Inayama Y, Nagashima Y, Miyagi Y, Uemura H, Saitoh K, Kubota Y, Hosaka M, Tanaka Y, Nakatani Y

Division of Anatomic and Surgical Pathology, Hospital of Yokohama City

Desmoplastic small round-cell tumor typically occurs in the abdomen of young men, but it can also develop at other anatomic sites and in older people, presenting greater diagnostic difficulties. We report a case of this tumor arising from the paratesticular region in a 43-year-old man. The tumor showed histologic, immunohistochemical, and ultrastructural evidence of multilineage differentiation, including epithelial, mesenchymal, and neuronal features. In addition, the presence of an EWS and WT1 chimeric messenger RNA was demonstrated by the reverse transcriptase-polymerase chain reaction using an EWS exon 7 primer and WT1 exon 8 and exon 9 primers, which revealed single polymerase chain reaction products with a junction of EWS exon 7 to WT1 exon 8. Our study demonstrates that desmoplastic small round-cell tumors of the paratesticular region share not only morphologic but also molecular genetic features with those of the abdomen and that reverse transcriptase-polymerase chain reaction analysis using paraffin sections is useful for a conclusive diagnosis.

13: Hum Pathol 1999 Apr;30(4):430-5

The expanding clinical spectrum of desmoplastic small round-cell tumor: a report of two cases with molecular confirmation.

Wolf AN, Ladanyi M, Paull G, Blaugrund JE, Westra WH

Department of Pathology, The Johns Hopkins Medical Institutions, Baltimore, MD, USA.

Desmoplastic small round cell tumor (DSRCT) is an aggressive neoplasm characterized by a consistent histological appearance, a unique immunohistochemical profile, and a specific chromosomal translocation. DSRCT is also hallmarked by distinctive clinical features. Most tumors arise in adolescent or young adult males, present as bulky abdominal masses, and diffusely spread along the peritoneal surface. We report two cases of DSRCT that do not fit this typical profile. One case involved the abdominal cavity of a 76-year-old woman. The other case arose in the parotid of a 22-year-old man. Histologically, the tumors showed the characteristic features of DSRCT. Immunohistochemically, the tumors showed positivity for cytokeratin, desmin, and neuron-specific enolase. Genetically, the tumors expressed the EWS-WT1 chimeric transcript. These two cases expand the differential diagnosis for poorly differentiated small-cell tumors that involve elderly patients or arise in the parotid. Moreover, they challenge the popular notion that DSRCT is a "blastomatous" tumor derived exclusively from the primitive mesothelium.

14: Radiology 1999 Mar;210(3):633-8

Desmoplastic small round cell tumor of the abdomen: radiologic-histopathologic correlation.

Pickhardt PJ, Fisher AJ, Balfe DM, Dehner LP, Huettner PC

Mallinckrodt Institute of Radiology, Washington University School of Medicine, St Louis, MO 63110, USA.

PURPOSE: To characterize the imaging features of desmoplastic small round cell tumor of the abdomen and correlate them with the histopathologic findings. MATERIALS AND METHODS: Eleven of 14 patients with desmoplastic small round cell tumor had primary abdominal involvement. In nine of these patients (mean age, 20 years), results of imaging studies (computed tomography in nine patients, ultrasonography [US] in three) and histopathologic specimens were retrospectively analyzed. RESULTS: The hallmark imaging feature was lobulated peritoneal masses (mean number, 4.4; range, 1-17) with a mean diameter of 5.0 cm (range, 2-12 cm). Omental and paravesical tumors were each present in six patients. Retroperitoneal masses were present in three patients. The tumors were well defined and hypoechoic at US. Heterogeneity due to tumor hemorrhage or necrosis was seen in seven patients. Ascites was present in five patients. Parenchymal and/or serosal hepatic metastases, punctate calcifications, nodular peritoneal thickening, lymphadenopathy, hydronephrosis, and bowel obstruction were less common associated findings. CONCLUSION: Bulky peritoneal soft-tissue masses without an apparent organ-based primary site are characteristic of intraabdominal desmoplastic small round cell tumor. Although the findings are nonspecific, this diagnosis can be considered in adolescents and young adults with characteristic imaging findings.

15: Ann Clin Lab Sci 1999 Jan-Mar;29(1):78-85

Intra-abdominal desmoplastic small round cell tumor: immunohistochemical evidence for up-regulation of autocrine and paracrine growth factors.

Froberg K, Brown RE, Gaylord H, Manivel C

Department of Pathology and Laboratory Medicine, University of Minnesota-Duluth, 55812, USA.

Desmoplastic small round cell tumors (DSRCT) are highly aggressive tumors typically involving the serosal surfaces of the peritoneum. Patients often present with abdominal pain, an abdominal mass, ascites or signs of intestinal obstruction. Cytogenetic and molecular studies have identified a characteristic t(11;22)(p13;q12) translocation within the tumor cells. The fused gene product apparently aligns the NH2-terminal domain (NTD) of the EWS gene to the zinc finger DNA-binding domain of the WT1 gene. This product could lead to loss of the tumor suppressor effect of the WT1 gene as well as to an increase in EWS driven expression of growth factors normally repressed by WT1. We investigated this latter possibility by performing immunohistochemical studies on formalin fixed tissue from 10 cases of DSRCT and five Wilms’ tumors using antibodies to insulin-like growth factor (IGF)-II, the latency associated peptide of transforming growth factor (TGF)-beta1, platelet-derived growth factor (PDGF)-AB chain and PDGF-alpha receptor, respectively. In general, tumor cells were strongly positive for these growth factors in DSRCT, while stromal cells were negative for IGF-II and positive for the other growth factors in parallel with the tumor cells. Wilms’ tumor cells were essentially negative for PDGF-AB chains, but positive for IGF-II, and the latency associated peptide of TGF-beta1 and variably positive for PDGF-alpha receptor. These findings support the proposed molecular mechanism of tumorigenesis for DSRCT and may help explain this tumor’s poor prognosis.

16: Hum Pathol 1999 Feb;30(2):239-42

Detection of EWS-WT1 fusion mRNA in ascites of a patient with desmoplastic small round cell tumor by RT-PCR.

Perez RP, Zhang PJ

Division of Medicine, Roswell Park Cancer Institute, Buffalo, NY, USA.

Desmoplastic small round cell tumor (DSRCT) is a rare, aggressive malignancy characterized cytogenetically by a unique translocation of chromosomes 11 and 22 [t(11:22)(p13:ql2)], resulting in fusion of the EWS and WT1 genes. The presence of a unique fusion mRNA in DSRCT allows disease detection and diagnosis by reverse transcription polymerase chain reaction (RT-PCR), as previously described in fixed paraffin-embedded material. In this report, EWS WT1 fusion mRNA was detected in ascites from a patient with DSRCT by RT-PCR. RT-PCR results confirmed the diagnoses of DSRCT and of malignant ascites at the molecular level. RT-PCR assays for specific molecular markers, such as EWS-WT1 fusion mRNA, are potentially powerful methods that can complement routine histological, cytological, and/or immunohistologic assays.

17: Acta Cytol 1997 Jul-Aug;41(4 Suppl):1402-6

Diagnosis of recurrent desmoplastic small round cell tumor by fine needle aspiration. A case report.

Logrono R, Kurtycz DF, Sproat IA, Allan RW, Inhorn SL

University of Wisconsin State Laboratory of Hygiene, Madison, USA.

BACKGROUND: Desmoplastic small round cell tumor (DSRCT) is a recently described neoplasm characterized by aggressive biology, occurrence in body cavities, expression of antigens from multiple cell lineages and a specific translocation between chromosomes 11 and 22. Most of the published information on this neoplasm is histologic. The case presented here enabled presentation of the cytomorphologic and immunocytochemical features of aspirated cytologic material obtained from this unique tumor. CASE: The cytologic, histologic, radiologic and clinical features of a DSRCT from a 17-year-old patient are presented. Although the initial diagnosis in this case was made on histology, recurrence was proven by fine needle aspiration biopsy (FNAB). CONCLUSION: The presence of sheets or clusters of small round malignant cells, associated with shards of dense fibroconnective tissue, in FNAB should lead the cytologist to consider the diagnosis of DSRCT.

18: Cancer Genet Cytogenet 1999 Jan 1;108(1):19-25

A combined cytogenetic and molecular approach to diagnosis in a case of desmoplastic small round cell tumor with a complex translocation (11;22;21).

Roberts P, Burchill SA, Beddow RA, Wheeldon J, Cullinane C, Lewis IJ

Regional Cytogenetics Unit, St. James’s University Hospital, Leeds, UK.

Desmoplastic small round cell tumor (DSRCT) has recently been described as a discrete tumor entity. It is distinguished from other small round cell tumors by its prominent desmoplastic quality, its preponderance in adolescent males, its almost exclusive intraabdominal location, a multi-immunophenotypic profile, and its aggressive nature. Diagnosis on histology alone is not always unequivocal. A recurrent t(11;22)(p13;q12) translocation has recently been described in this tumor, and a chimeric RNA fusion product formed from the WT1 and EWS genes is detectable by reverse transcriptase-polymerase chain reaction (RT-PCR). We describe the use of a multi-faceted approach using conventional G-banding, fluorescence in situ hybridization (FISH) and RT-PCR to assist the diagnosis of a case of DSRCT with a complex variant t(11;22;21)(p13;q12;q22.1) translocation and demonstrate the value of a combined approach to genetic investigation of solid tumors.

19: Med Pediatr Oncol 1999 Feb;32(2):97-101

Synovial sarcoma mimicking desmoplastic small round-cell tumor: critical role for molecular diagnosis.

Cole P, Ladanyi M, Gerald WL, Cheung NK, Kramer K, LaQuaglia MP, Kushner BH

Department of Pediatrics, Memorial Sloan-Kettering Cancer Center, New York, New York 10021, USA.

BACKGROUND: The identification of recently described nonrandom chromosomal defects specific for various small round-cell and spindle-cell sarcomas can eliminate diagnostic uncertainty arising from the clinical and histopathologic overlap of soft tissue neoplasms. METHODS: A 26-year-old man presented with bulky abdominal-pelvic disease. Immunohistochemical and molecular studies on tumor were performed. Treatment was instituted using cycles of high-dose cyclophosphamide (4,200 mg/m2) with doxorubicin (75 mg/m2). RESULTS: Clinical findings pointed to desmoplastic small round-cell tumor. The tumor was histologically undifferentiated and immunoreactive for vimentin but negative for other markers. Reverse transcriptase-polymerase chain reaction revealed the SYT/SSX2 fusion transcript of the synovial sarcoma t(X;18) chromosomal rearrangement. The high-dose chemotherapy, plus surgery, achieved a complete remission, but recurrent disease emerged 13 months from diagnosis. CONCLUSIONS:

This clinically unique case of synovial sarcoma highlights how the use of now readily available molecular techniques will allow more accurate appraisals of the incidence and anatomic distribution of soft tissue neoplasms-information that bears upon pathogenesis and treatment. This case confirms the utility of high-dose alkylator-based therapy for synovial sarcoma. It also demonstrates that with nonlocalized solid tumors, the eradication of minimal residual disease remains an elusive goal. One alternative involves immunologic attack against markers derived from tumor-specific chromosomal defects such as those found in our patient.

20: Pediatr Dev Pathol 1999 Mar-Apr;2(2):188-92

Variant EWS-WT1 chimeric product in the desmoplastic small round cell tumor.

Chan AS, MacNeill S, Thorner P, Squire J, Zielenska M

Department of Pediatric Laboratory Medicine, The Hospital for Sick Children, 555 University Avenue, Toronto, Ontario, Canada M5G 1X8.

Chromosome translocations found in neoplasms often result in the creation of hybrid genes encoding chimeric proteins. Desmoplastic small round cell tumor (DSRCT) is a recently described aggressive malignancy associated with a unique chromosomal translocation t(11;22)(p13;q12). This translocation has recently been characterized, revealing the rearrangement and fusion of the WT1 gene on chromosome 11 to the EWS gene on chromosome 22. Fusion of these two genes results in the production of a putative oncogenic protein composed of the zinc finger DNA-binding domains of WT1 linked to the potential transcriptional regulatory domains of EWS. The typical chimeric transcript consists of the first 7 exons of EWS and the last 3 exons of WT1. We report here the first case of DSRCT with a variant EWS-WT1 chimeric product that includes 9 exons of EWS and 3 exons of WT1.

21: Radiographics 1999 Jan-Feb;19(1):252-4

General case of the day. Desmoplastic small round cell tumor of the abdomen with scrotal metastases.

Takhtani D, Saleeb SF, Teplick SK

Department of Radiology, University of South Alabama College of Medicine, Mobile 36617, USA.

22: J Radiol 1998 Dec;79(12):1506-8

[Intra-abdominal small round-cell desmoplastic tumor: ultrasonographic and computed tomographic aspects. Apropos of a case].

N’Dri K, Aguehounde C, Konan A, Ouattara ND, Abby CB

Service de radiologie PISAM: Polyclinique internationnale Sainte Anne-Marie, Abidjan.

We report a case of small round-cell desmoplastic tumor located in the abdomen. We describe the ultrasound and CT features of this uncommon tumor with poor prognosis.

23: Pediatr Dev Pathol 1999 Jan-Feb;2(1):33-41

Expression of WT1 in pediatric small cell tumors: report of two cases with a possible mesothelial origin.

Thorner P, Squire J, Plavsic N, Jong R, Greenberg M, Zielenska M

Department of Pediatric Laboratory Medicine, Hospital for Sick Children Toronto, Ontario, Canada.

The WT1 gene is normally expressed in fetal kidney and mesothelium, and its expression has been suggested as a marker for Wilms tumor and mesothelioma. We examined WT1 expression levels by reverse-transcriptase polymerase chain reaction (RT-PCR) in 38 childhood small-cell tumors including Wilms tumor, embryonal and alveolar rhabdomyosarcoma, Ewing sarcoma, lymphoma, desmoplastic small round-cell tumor (DSRCT), synovial sarcoma, extrarenal rhabdoid tumor, and two tumors that were atypical for this group of tumors. WT1 expression was only detected in Wilms tumor, rhabdoid tumor, and in these two cases of uncertain histogenesis. Both arose in the peritoneal cavity and by immunohistochemistry were diffusely positive for vimentin, keratin, and desmin. Tonofilaments were identified by electron microscopy in one of the cases. RT-PCR failed to detect the t(11;22) translocation associated with DSRCT in either case. Our results suggest that WT1 expression is an unusual feature of childhood non-Wilms tumors and, in the right setting, it may indicate a mesothelial origin. The expression of WT1 may play a role in mesodermal cells acquiring epithelial characteristics, a concept supported by the mixed epithelial and mesenchymal phenotype of these two cases.

24: Ann Clin Lab Sci 1998 Nov-Dec;28(6):386-93

Intra-abdominal desmoplastic small round cell tumor: immunohistochemical evidence for up-regulation of autocrine and paracrine growth factors.

Froberg K, Brown RE, Gaylord H, Manivel C

Department of Pathology and Laboratory Medicine, University of Minnesota-Duluth 55812, USA.

Desmoplastic small round cell tumors (DSRCT) are highly aggressive tumors typically involving the serosal surfaces of the peritoneum. Patients often present with abdominal pain, an abdominal mass, ascites or signs of intestinal obstruction. Cytogenetic and molecular studies have identified a characteristic t(11;22)(p13;q12) translocation within the tumor cells. The fused gene product apparently aligns the NH2-terminal domain (NTD) of the EWS gene to the zinc finger DNA-binding domain of the WT1 gene. This product could lead to loss of the tumor suppressor effect of the WT1 gene as well as to an increase in EWS driven expression of growth factors normally repressed by WT1. We investigated this latter possibility by performing immunohistochemical studies on formalin fixed tissue from 10 cases of DSRCT and five Wilms’ tumors using-antibodies to insulin-like growth factor (IGF)-II, the latency associated peptide of transforming growth factor (TGF)-beta 1, platelet-derived growth factor (PDGF)-AB chain and PDGF-alpha receptor, respectively. In general, tumor cells were strongly positive for these growth factors in DSRCT, while stromal cells were negative for IGF-II and positive for the other growth factors in parallel with the tumor cells. Wilms’ tumor cells were essentially negative for PDGF-AB chains, but positive for IGF-II, and the latency associated peptide of TGF-beta 1 and variably positive for PDGF-alpha receptor. These findings support the proposed molecular mechanism of tumorigenesis for DSRCT and may help explain this tumor’s poor prognosis.

25: Australas Radiol 1998 Nov;42(4):377-8

Desmoplastic small round cell tumour.

Tan TH, Ong KL, Au YM

Radiology Department, North District Hospital, Fanling, Kowloon, Hong Kong.

The present report describes a rare case of primary desmoplastic small cell tumour of the recto-sigmoid colon with hepatic metastases and lymphadenopathy. There are no pathognomonic radiological features and often their features overlap with other diseases including lymphoma. Histology is necessary to confirm this diagnosis. Unfortunately despite aggressive therapy, the prognosis for this disease is poor.

26: Pathol Res Pract 1998;194(10):693-700

Desmoplastic small round cell tumor: RT-PCR analysis and immunohistochemical detection of the Wilm’s tumor gene WT1.

Barnoud R, Delattre O, Peoc’h M, Pasquier D, Plantaz D, Leroux D, Pasquier B

Departement de Pathologie, Centre Hospitalier Universitaire, Grenoble, France.

Desmoplastic small round cell tumor is an aggressive neoplasm first described in 1991. Recently, a reciprocal translocation t(11;22)(p13;q12) has been characterized by conventional cytogenetic studies and molecular analysis. This translocation involves the Ewing’s sarcoma gene on chromosome 22 and the Wilms’ tumor gene WT1 on chromosome 11. The chimeric transcript corresponding to the fusion gene could be detected by the reverse transcriptase-polymerase chain reaction (RT-PCR). Using an anti-WT1 antibody, the WT1 part of the putative chimeric protein could be recognized by immunohistochemistry. We describe two well-characterized cases of intraabdominal desmoplastic small round cell tumor in two male patients aged 14 and 28 with both RT-PCR analysis and immunostaining for WT1. In this report, we insist on the necessity to increase the RT-PCR analysis in DSRCT in order to obtain a precise differential diagnosis. In addition, WT1 immunostaining may serve as a useful diagnostic marker for DSRCT.

27: Am J Surg Pathol 1998 Nov;22(11):1314-27

Desmoplastic small round cell tumor: II: an ultrastructural and immunohistochemical study with emphasis on new immunohistochemical markers.

Ordonez NG

The University of Texas M.D. Anderson Cancer Center, Houston 77056, USA.

In order to investigate the histogenesis and facilitate the diagnosis of desmoplastic small round cell tumor (DSRCT), 39 cases were studied by immunohistochemical methods using a large battery of antibodies directed against a wide variety of epithelial, mesenchymal, and neural-associated proteins. Sixteen of these tumors were also studied by electron microscopy. Thirty-seven of 39 cases reacted for cytokeratin using a "cocktail" of 3 monoclonal antibodies (CAM 5.2/AE1/AE3), 39/39 for desmin, 24/25 for epithelial membrane antigen, 22/27 for vimentin, 18/25 for neuron-specific enolase, 10/15 for CD57 (Leu-7), 3/19 for synaptophysin, 1/22 for chromogranin, 3/19 for muscle-specific actin, 3/16 for alpha-smooth-muscle actin, 11/16 for CD15 (Leu-M1), 5/12 for CA-125, 6/17 for CD99, 9/10 for MOC-31, 2/6 for NB84, 5/7 for Ber-EP4, and 8/9 for the Wilms tumor (WT1) protein. No staining was obtained in any of the cases tested for cytokeratin 5/6 or 20, neurofilament proteins, glial fibrillary acidic protein, peripherin, CA19-9, thrombomodulin, alphafetoprotein, carcinoembryonic antigen, TAG-72 (B72.3), placental alkaline phosphatase, S-100 protein, HMB-45, myoglobin, or for the two myogenic regulatory proteins myogenin and MyoD1. A frequent ultrastructural finding was the presence of juxtanuclear aggregates of intermediate filaments, but microfilaments with densities or Z-band-like material suggestive of either smooth or skeletal muscle differentiation were not seen in any case. Dendritic-like processes containing microtubules and dense core granules were seen in four tumors and all of these tumors reacted for at least one of the neural markers investigated. Although ultrastructural and immunohistochemical studies confirmed previous observations that DSRCTs present epithelial, mesenchymal, and neural phenotypes, a great variation was found in the frequency of expression of the different markers used to demonstrate each line of cell differentiation. The absence of expression of cytokeratin 5/6 and thrombomodulin together with positive staining for CD15, MOC-31, and Ber-EP4 argues against the possible mesothelial origin that has been suggested for this tumor. Additionally since none of the tumors reacted for myogenin or MyoD1, desmin expression in DSRCT cannot be regarded as evidence of skeletal muscle differentiation. Although the histogenesis of DSRCT remains unknown, it is believed that this tumor originates from a progenitor cell with potential for multiphenotypic differentiation.

Review of reported cases

28: Am J Surg Pathol 1998 Nov;22(11):1303-13

Desmoplastic small round cell tumor: I: a histopathologic study of 39 cases with emphasis on unusual histological patterns.

Ordonez NG

The University of Texas M.D. Anderson Cancer Center, Houston 77056, USA.

The clinical and histological features of 39 cases of desmoplastic small round cell tumor (DSRCT) diagnosed at M.D. Anderson Cancer Center are presented. Thirty-two of the patients were men and seven were women ranging in age from 10 to 41 years (mean, 25 years). Twenty-five of the 35 patients for whom follow-up information was available died of widespread metastases 8 to 50 months (mean, 25.2 months) from the time of their diagnosis and the remaining 10 were alive with disease. With the exception of two cases that occurred in the liver and in the scrotum, respectively, all of the cases originated within the abdominal and/or pelvic peritoneum. Eight tumors also involved the retroperitoneum. Although the characteristic histologic pattern of "small, blue cells" embedded in a dense fibrous stroma was seen in most cases, about one third of the tumors exhibited a wide range of morphologic features. The recognition of these uncommon morphologic variants of DSRCT is of paramount importance to avoid a misdiagnosis because these tumors could potentially be confused with other neoplastic conditions.

29: Cancer Genet Cytogenet 1998 Oct 15;106(2):156-8

Novel breakpoints of the EWS gene and the WT1 gene in a desmoplastic small round cell tumor.

Shimizu Y, Mitsui T, Kawakami T, Ikegami T, Kanazawa C, Katsuura M, Obata K,

Yamagiwa I, Hayasaka K

Department of Pediatrics, Yamagata University School of Medicine, Japan.

We report here a 15-year-old boy with an intraabdominal desmoplastic small round cell tumor (DSRCT). Cytogenetic analysis of the tumor cells showed the chromosomal translocation (11;22). Reverse-transcriptase polymerase chain reaction and sequencing analysis revealed a chimeric transcriptional message of the EWS gene exon 10 fused to the WT1 gene exon 8. The typical chimeric transcript seen in DSRCT is an in-frame fusion of EWS exon 7 to WT1 exon 8. The tumor in this case had a novel and longer chimeric transcript, which should be a potent transcription factor. Genetic analysis is a very powerful and specific aid in the differential diagnosis of small round cell tumors.

30: Mod Pathol 1998 Oct;11(10):923-8

The role of fine-needle aspiration biopsy in the initial diagnosis of pediatric bone and soft tissue tumors: an institutional experience.

Kilpatrick SE, Ward WG, Chauvenet AR, Pettenati MJ

Department of Pathology and Laboratory Medicine, University of North Carolina,

The use of fine-needle aspiration biopsy (FNAB) in the initial evaluation of pediatric bone and soft tissue tumors is controversial, especially for those patients being considered for histiogenetic-specific therapeutic protocols, e.g., the Intergroup Rhabdomyosarcoma Study Group, the Pediatric Oncology Group. We retrospectively reviewed 33 consecutive FNAB specimens (28 primary tumors, 5 metastases) from 32 pediatric patients (< or = 19 yr of age), none of whom had a previously established tumor diagnosis. In one patient, FNAB of the primary tumor and a presumed axillary metastasis were obtained concomitantly. The cytomorphologic analysis included osteosarcoma, eight patients; rhabdomyosarcoma, five; neuroblastoma, five; Ewing’s sarcoma/primitive neuroectodermal tumor, four; Langerhans’ cell histiocytosis, three; and one each synovial sarcoma, undifferentiated sarcoma, infantile myofibromatosis, fibroma, chondroblastoma, chondromyxoid fibroma, and desmoplastic small round-cell tumor. Ancillary studies, e.g., immunocytochemical analysis, were used in 13 cases. Cytogenetic analysis helped to confirm one Ewing’s sarcoma [t (11;22) (q24;q12)] and one synovial sarcoma [t(X;18) (p11;q11)]. With adequate FNAB specimens, a histogenetic-specific diagnosis was rendered in 27 (93%) of 29 cases, and all were correctly recognized as either benign or malignant. One case each of Langerhans’ cell histiocytosis, chondroblastoma, and infantile myofibromatosis yielded unsatisfactory specimens. Fibroma and desmoplastic small round-cell tumor were initially misclassified as nodular fasciitis and rhabdomyosarcoma, respectively. Of 18 patients clinically eligible for histogenetic-specific therapy protocols, an accurate diagnosis was obtained in 17 patients. With a multidisciplinary approach and judicious use of ancillary studies, FNAB represents a highly accurate and cost-effective technique for the diagnosis of pediatric bone and soft tissue tumors, especially sarcomas, and should be considered as a viable diagnostic technique for pediatric therapeutic protocols.

31: J Clin Oncol 1998 Sep;16(9):3028-36

Clinical, pathologic, and molecular spectrum of tumors associated with t(11;22)(p13;q12): desmoplastic small round-cell tumor and its variants.

Gerald WL, Ladanyi M, de Alava E, Cuatrecasas M, Kushner BH, LaQuaglia MP, Rosai J

Department of Pathology, Memorial Sloan-Kettering Cancer Center, New York, NY

PURPOSE: Intense investigation has reshaped concepts about undifferentiated tumors occurring in young people (small round-cell tumors). Tumors associated with t(11;22)(p13;q12) and descriptively designated desmoplastic small round-cell tumor (DSRCT) are a distinctive, rare, poorly understood member of this family. We reviewed 109 cases of DSRCT to further characterize this entity better. METHODS: Clinical information and histology were reviewed. Immunohistochemistry and immunoblotting were performed using standard techniques. Chimeric EWS-WT1 RNA and DNA were detected by polymerase chain reaction (PCR) and genomic translocation breakpoints mapped in a subset of cases. RESULTS: There were 90 males and 19 females from 6 to 49 years of age (mean, 22 years). A total of 103 had tumor in the abdominal cavity, four in the thoracic region, one in the posterior cranial fossa, and one in the hand. Typical histologic and immunohistochemical features were usually evident in well-sampled tumors, but variations in cellularity, stromal components, cytology, architecture, and immunoreactivity occurred. Tumor cells were usually reactive with antibodies to keratin (67 of 78 cases, 86%), epithelial membrane antigen (50 of 54, 93%), vimentin (64 of 66, 97%), desmin (70 of 78, 90%), neuron-specific enolase (60 of 74, 81%), and the EWS-WT1 chimeric protein (25 of 27, 93%); typically nonreactive for muscle common actin (one of 58, 2%), myogenin (zero of eight, 0%), and chromogranin (one of 46, 2%); and variably reactive for MIC2 (nine of 47, 20%) and p53 (five of 17 with > 20% tumor cells reactive). Functional EWS-WT1 gene fusion was evident in 25 of 26 cases with genomic breakpoints in WT1 intron 7, and EWS introns 7, 8, and 9. Prognosis in general is poor, but tumors are responsive to aggressive therapy. CONCLUSION:

This large review identifies a greater degree of clinical, pathologic, and molecular variation than originally appreciated for tumors associated with t(11;22)(p13;q12). Translocation and functional fusion of the EWS and WT1 genes appears to be a consistent feature of this unique tumor.

32: Ann Surg Oncol 1998 Jul-Aug;5(5):416-22

Desmoplastic small round cell tumors: prognostic indicators and results of surgical management.

Schwarz RE, Gerald WL, Kushner BH, Coit DG, Brennan MF, La Quaglia MP

Department of Surgery, Memorial Sloan-Kettering Cancer Center, New York, New York 10021, USA.

BACKGROUND: Desmoplastic small round cell tumors (DSRCT or DSCT) are rare aggressive cancers of adolescence and early adulthood. There are few reported series to guide clinical therapy. This study correlates survival with treatment variables, including aggressive surgical debulking. METHODS: Thirty-two patients with documented DSRCT received treatment at our institution. Demographic, clinical, and treatment variables were correlated with progression-free survival using log-rank statistics. RESULTS: Thirty patients were male (96%), and two were female (4%), with a median age at diagnosis of 22 years. The primary site of disease in 97% of cases was the abdomen or pelvis. Twenty-nine patients (91%) had extensive disease involving peritoneal surfaces, lymph nodes, or discontinuous organs. All 32 patients received systemic chemotherapy. Fifteen (47%) underwent tumor debulking greater than 90% at diagnosis or during therapy. A complete or very good response to therapy occurred in 13 patients, and depended on surgical removal of bulk disease in all. Thirteen patients remained progression-free, but three of these patients died from treatment toxicity. Improved survival was correlated with a complete or very good partial response to multimodality therapy, surgical debulking of more than 90% either before or after chemotherapy, and use of the P6 protocol. CONCLUSIONS: DSRCT is an aggressive cancer that occurs predominantly in young males. Improved survival is correlated with intense chemotherapy and aggressive resection.

33: Am J Surg Pathol 1998 Aug;22(8):1026-32

Intraabdominal desmoplastic small round cell tumor with EWS/ERG fusion transcript.

Ordi J, de Alava E, Torne A, Mellado B, Pardo-Mindan J, Iglesias X, Cardesa A

Department of Pathology, IDIBAPS Hospital Clinic, Facultat de Medicina, Universitat de Barcelona, Spain.

This report describes an intraabdominal small cell tumor in a 37-year-old woman, with clinical, topographic, and morphologic features highly suggestive of the desmoplastic small round cell tumor. Immunohistochemical analysis revealed a polyphenotypic profile consistent with this tumor—positivity for keratin, epithelial membrane antigen, neuron-specific enolase, vimentin, and desmin—but, in addition, a strong membranous immunoreactivity for CD99 (MIC2 protein). Reverse transcription polymerase chain reaction revealed a EWS/ERG fusion transcript characteristic of the Ewing’s sarcoma/peripheral primitive neuroectodermal tumor group of tumors, rather than the EWS/WT1 chimeric transcript typical of the desmoplastic small round cell tumor. This is the third report of a hybrid tumor with features of the desmoplastic small round cell tumor and Ewing’s sarcoma/peripheral primitive neuroectodermal tumor, and the first one with the EWS/ERG fusion gene. Our case shows the existence of some overlap between these two groups of tumors, which are considered to be histogenetically different, and the need for further studies of molecular characterization of small cell tumors, especially in those with atypical morphologic or immunohistochemical features.

34: Tumori 1998 May-Jun;84(3):412-6

Complete response to chemotherapy in intra-abdominal desmoplastic small round cell carcinoma. A case report.

De Lena M, Caruso ML, Marzullo F, Mancarella S, Armentano R, Ventrella V, Guida M

Medical Oncology Division, IRCCS Istituto Oncologico, Bari, Italy.

AIMS AND BACKGROUND: The authors report the case of a 23-year-old woman affected by intra-abdominal desmoplastic small round cell tumor (DSRCT) who obtained a complete response to multiagent chemotherapy. DSRCT is a rare, highly aggressive neoplasm generally arising in young people and seldom in females (about 20 cases described in the literature). METHODS: The patient underwent surgical resection of a large 15 x 15 cm mass located in the right lower abdominal quadrant, but after only 2 months later, two liver metastasis were noted. Thus, she was subjected to an aggressive antineoplastic treatment consisting of three groups of alternating non-cross resistant multiagent regimens administered every 21 days (cis-platin-etoposide-adriamycin-bleomicin; gemcitabine-ifosfamide-dacarbazine; methotrexate-5-fluorouracil-folinic acid) for a total of 9 administrations. RESULTS: After one cycle of treatment including the administration of all the three alternated schemes of chemotherapy, a complete disappearance of liver disease was noted. The treatment was relatively well-tolerated and the toxicity was acceptable. At present, after 15 months from diagnosis and 12 months after starting chemotherapy, the patient is disease-free and in good health. CONCLUSIONS: Even though this study regards only a single patient, it is noteworthy because of the rarity of this neoplasm and because of the infrequent complete responses reported in the literature. The efficacy and manageability of the treatment, suggests that both the timing and schedule used could constitute an important therapeutical option for this aggressive and poorly chemo-responsive tumor.

35: Diagn Mol Pathol 1998 Feb;7(1):24-8

Molecular variants of the EWS-WT1 gene fusion in desmoplastic small round cell tumor.

Antonescu CR, Gerald WL, Magid MS, Ladanyi M

Department of Pathology, Human Genetics, Memorial Sloan-Kettering Cancer Center, New York, New York 10021, USA.

We report two cases of desmoplastic small round cell tumor (DSRCT) with novel molecular variants of the specific EWS-WT1 gene fusion. This fusion usually encodes a chimeric RNA with an in-frame junction of exon 7 of EWS to exon 8 of WT1. In one variant patient, the EWS-WT1 fusion transcript contained an in-frame junction of exon 9 of EWS to exon 8 of WT1. Moreover, in this patient the tumor arose in the hand, an extremely unusual site for DSRCT. In the second patient, an in-frame junction of exon 10 of EWS to exon 8 of WT1 was present. These two cases of DSRCT show that the molecular variability in the EWS breakpoint observed in the EWS-FLI1 fusion of Ewing’s sarcoma can occur in DSRCT as well. This type of heterogeneity is relevant to the interpretation of molecular diagnostic assays and could also affect the functional properties of the encoded chimeric transcription factors.

36: Diagn Cytopathol 1998 Jun;18(6):449-52

Intraabdominal desmoplastic small round cell tumor: cytopathologic findings in two cases.

Ali SZ, Nicol TL, Port J, Ford G, John K. Frost

Cytopathology Laboratory, Department of Pathology, Johns Hopkins Hospital, Baltimore, Maryland 21287, USA.

Intraabdominal desmoplastic small round cell tumor (DSRCT) is an extremely rare entity. This study describes fine-needle aspiration, ascitic fluid, and touch imprint cytomorphology of DSRCT in 2 patients with extensive abdomino-pelvic disease. Cytopathologic features were unique and showed good morphologic correlation with subsequent histology of the resected tumor. Immunocytochemical profile and differential diagnosis with other small round cell tumors in this age group are also discussed.

37: Bone Marrow Transplant 1998 May;21(9):961-3

Benefit of aggressive multimodality therapy with autologous stem cell support for intra-abdominal desmoplastic small round cell tumor.

Mazuryk M, Paterson AH, Temple W, Arthur K, Crabtree T, Stewart DA

Medical Oncology, Tom Baker Cancer Centre and University of Calgary, Alberta, Canada.

A case is described of a 19-year-old man with poor prognosis intra-abdominal desmoplastic small round cell tumor, who achieved a durable complete remission after aggressive multimodality treatment. He was diagnosed with a large peri-rectal mass and bulky metastases to the peritoneum, omentum and liver. He achieved a partial response to six courses of chemotherapy with VAC (vincristine, adriamycin, actinomycin, cyclophosphamide) and VIP (VP-16, ifosfamide, cisplatin). This was followed by resection of the omentum and cryotherapy to six of the liver lesions. He then achieved a complete response following high-dose busulfan 16 mg/kg and melphalan 140 mg/m2 with autologous stem cell support. Finally, pelvic radiotherapy was given to consolidate the remission. Twenty-six months following his diagnosis, and 19 months after the transplant, he remains well with no clinical or radiologic evidence of recurrent disease. This case report suggests a role for autologous stem cell transplantation as part of multimodality therapy for this unusual and aggressive malignancy.

38: Oncogene 1998 Apr 16;16(15):1973-9

The desmoplastic small round cell tumor t(11;22) translocation produces EWS/WT1 isoforms with differing oncogenic properties.

Kim J, Lee K, Pelletier J

Department of Biochemistry, McGill University, Montreal, Quebec, Canada.

Structural alterations of the Wilms’ tumor locus (WT1) at 11p13 have been implicated in the etiology of two human cancers—Wilms’ tumor (WT), a pediatric renal malignancy, and Desmoplastic Small Round Cell Tumor (DSRCT), an aggressive cancer of the abdominal serosal lining with predilection for male adolescents. Germline mutations within the WT1 tumor suppressor gene predispose to WT and are associated with congenital malformations of the urogenital system, and somatic mutations are associated with initiation of transformation in WTs. In DSRCT, a recurrent translocation, t(11;22)(p13;q12), fuses the amino terminal domain of the EWS1 gene product to three of the four WT1 zinc fingers. Two EWS/WT1 isoforms are generated as a result of an alternative splicing event between zinc fingers III and IV, inserting or removing three amino acids (+/- KTS). We demonstrate that introduction of EWS/WT1(-KTS) into NIH3T3 cells causes their tumorigenic transformation as determined by: formation of transformed foci on a monolayer of cells; anchorage-independent growth; and tumor formation in nude mice. EWS/WT1(+KTS) showed no transforming potential in these assays. These results indicate the oncogenic effect of the t(11;22) translocation is mediated by the EWS/WT1(-KTS) isoform and that fusion of the EWS amino terminal domain to the WT1 DNA binding domain produces a chimeric product showing a gain of function.

39: Virchows Arch 1998 Feb;432(2):135-41

Desmoplastic small round cell tumour of unknown primary origin with lymph node and lung metastases: histological, cytological, ultrastructural, cytogenetic and molecular findings.

Backer A, Mount SL, Zarka MA, Trask CE, Allen EF, Gerald WL, Sanders DA, Weaver DL

Department of Pathology, University of Vermont and Fletcher Allen Health Care, Burlington 05405, USA.

Desmoplastic small round cell tumour (DSRCT) is an extremely aggressive neoplasm belonging to the family of "small round blue cell tumours", which includes primitive neuroectodermal tumour (PNET), Wilms’ tumour and Ewing’s sarcoma. DSRCT is considered to be a neoplasm derived from a primitive cell. It is immunohistochemically reactive with epithelial, neuronal and mesenchymal cell markers, demonstrating divergent differentiation along three cell lines. Originally thought to arise from serosal surfaces, the tumour has recently been reported in the central nervous system and ovary. The tumour in this case is a neoplasm that meets the histological, immunohistochemical, cytological and cytogenetic criteria of DSRCT; it is not associated with serosal membranes, and it has supraclavicular and axillary lymph node deposits and multiple pulmonary and brain metastases. Tumour cells from our case show cytogenetic similarities with Ewing’s sarcoma and PNET. Electron microscopic findings suggest similarities between DSRCT and Wilms’ tumour. Cloning and sequencing of PCR products showed in-frame fusion of EWS exon 7 to WT1 exon 8.

40: Am J Surg Pathol 1998 Mar;22(3):327-32

Monoclonal antibody NB84 in the differential diagnosis of neuroblastoma and other small round cell tumors.

Miettinen M, Chatten J, Paetau A, Stevenson A

Armed Forces Institute of Pathology, Department of Soft Tissue Pathology, Washington, DC 20306, USA.

Two hundred fifty-five well-characterized formaldehyde-fixed and paraffin-embedded small round cell tumors mainly from children and young adults including 105 neuroblastomas were immunohistochemically analyzed with the NB84 monoclonal antibody raised to neuroblastoma cells. Most of the undifferentiated neuroblastomas (21 of 22) and all 83 differentiated neuroblastomas reacted with NB84, but none of these tumors were CD99 positive. Compared with synaptophysin, NB84 was more sensitive, although less specific, in the identification of neuroblastoma in formaldehyde-fixed tissue. In addition to neuroblastoma, skeletal and extraskeletal Ewing’s sarcoma and medulloblastoma showed NB84 reactivity in approximately 20% of cases, and 50% of desmoplastic small round cell tumors showed positive cells, usually in smaller numbers than the neuroblastomas. The NB84 reactivity was seen slightly more commonly in morphologically defined (rosette-positive) cases of peripheral primitive neuroectodermal tumors than in Ewing’s sarcoma. However, the NB84 positivity did not correlate with the expression of other neural markers (neurofilament proteins, CD57, and synaptophysin) in these tumors. All other small round cell tumors including rhabdomyosarcomas, Wilms’ tumors, and lymphomas were NB84 negative. In the case of NB84-positive tumors other than neuroblastoma, their specific reactivity for other markers was useful (Ewing’s sarcoma CD99 positive, desmoplastic small round cell tumor desmin and keratin positive). The NB84 monoclonal antibody is a useful reagent to separate neuroblastoma from other small round cell tumors. In problem cases it is best used in a panel together with other markers that address the significant differential diagnostic alternatives.

41: Hum Pathol 1998 Mar;29(3):294-9

CA 125 production in desmoplastic small round cell tumor: report of a case with elevated serum levels and prominent signet ring morphology.

Ordonez NG, Sahin AA

University of Texas MD Anderson Cancer Center, Houston 77030, USA.

Serum assays for CA 125 are often used in the diagnosis and follow-up of patients with gynecologic neoplasms. A case of a 34-year-old woman with desmoplastic small round cell tumor (DSRCT) having an unusual morphology, including the presence of a signet ring cell component, and high serum CA 125 levels that was initially diagnosed as poorly differentiated carcinoma of the ovary is herein reported. Ultrastructurally, the signet ring appearance was shown to be the result of either the presence of intracytoplasmic vacuoles or dilatation of the intercellular space. Immunoperoxidase staining showed strong reactivity for desmin, keratin, vimentin, and CA 125. Immunohistochemical studies were performed on six additional DSRCTs but only two showed focal staining for CA 125. Because the patient’s CA 125 serum level decreased after she received chemotherapy and her tumor was removed, and it became elevated again when the disease recurred, it is possible that CA 125 could be used as a marker of persistent and recurrent disease in those uncommon cases of DSRCT in which there are elevated serum levels of this marker at the onset of treatment.

42: Med Pediatr Oncol 1998 Jan;30(1):34-9

High-dose rate intraoperative radiation therapy for pediatric solid tumors.

Merchant TE, Zelefsky MJ, Sheldon JM, LaQuaglia MB, Harrison LB

Memorial Sloan-Kettering Cancer Center, New York, NY, USA.

BACKGROUND: Sixteen pediatric patients with solid tumors received treatment on a protocol designed to test the feasibility and safety of high-dose rate intraoperative radiation therapy (IOHDR) via a remote afterloader. PATIENTS AND METHODS: Patients with Ewing’s sarcoma (n = 5), rhabdomyosarcoma (n = 3), synovial cell sarcoma (n = 2), Wilms tumor (n = 2), osteosarcoma, immature teratoma, desmoplastic small round cell tumor, and inflammatory fibrosclerosis were included. IOHDR was used in the initial management of nine patients and at the time of recurrence in seven. Indications for treatment included gross residual disease in 5 and suspected microscopic disease in 11. The general sites treated were the abdomen (n = 3), chest-wall/thoracic cavity (n = 7), and pelvis (n = 6). All of the patients received multiagent chemotherapy prior to the IOHDR procedure, and 5 had been previously treated with external beam radiation therapy. Separate from the procedure during which IORT was performed, 9 patients underwent an attempt at resection at the time of their initial presentation. A dose of 1200 cGy was prescribed to a depth of 0.5 cm from the surface of a multichannel tissue-equivalent applicator. Complications ascribed to IOHDR included an abscess, delayed wound healing, and cytopenia. Four patients received supplemental external beam radiation therapy to the IOHDR site. At the time of IOHDR, 3 patients had disseminated disease within the pleural cavity and one had pulmonary metastases. RESULTS: With a median follow-up of 18 months, the actuarial rates of local control, metastasis-free, and overall survival at 2 years were 61%, 51%, and 54%, respectively. The patterns of failure were local (n = 1), distant (n = 1), and local + distant (n = 1). Two patients are alive with active disease. Nine are alive with no evidence of disease and the remaining 5 are dead from disease (n = 2), other causes (n = 1), or treatment (n = 2). CONCLUSIONS: The potential to improve local control with high doses of radiation should be balanced against the risk of late effects. The ability to confine the dose of radiation to the primary site and decrease the dose to normal tissues makes IOHDR an important adjunct to external beam radiation therapy. IOHDR can be a safe and integral component in the management of pediatric solid tumors.

43: Nat Genet 1997 Nov;17(3):309-13

The EWS-WT1 translocation product induces PDGFA in desmoplastic small round-cell tumour.

Lee SB, Kolquist KA, Nichols K, Englert C, Maheswaran S, Ladanyi M, Gerald WL, Haber DA

Massachusetts General Hospital Cancer Center, Charlestown.

Chromosomal translocations resulting in chimaeric transcription factors underlie specific malignancies, but few authentic target genes regulated by these fusion proteins have been identified. Desmoplastic small round-cell tumour (DSRT) is a multiphenotypic primitive tumour characterized by massive reactive fibrosis surrounding nests of tumour cells. The t(11;22)(p13;q12) chromosomal translocation that defines DSRT produces a chimaeric protein containing the potential transactivation domain of the Ewing-sarcoma protein (EWS) fused to zinc fingers 2-4 of the Wilms tumour suppressor and transcriptional repressor WT1 (refs 2,3). By analogy with other EWS fusion products, the EWS-WT1 chimaera may encode a transcriptional activator whose target genes overlap with those repressed by WT1 (ref. 4). To characterize its functional properties, we generated osteosarcoma cell lines with tightly regulated inducible expression of EWS-WT1. Expression of EWS-WT1 induced the expression of endogenous platelet-derived growth factor-A (PDGFA), a potent secreted mitogen and chemoattractant whose promoter contains the many potential WT1-binding sites. Native PDGFA was not regulated by wild-type WT1, indicating a difference in target gene specificity between this tumour suppressor and its oncogenic derivative. PDGFA was expressed within tumour cells in primary DSRT specimens, but it was absent in Wilms tumours expressing WT1 and Ewing sarcomas with an EWS-Fli translocation. We conclude that the oncogenic fusion of EWS to WT1 in DSRT results in the induction of PDGFA, a potent fibroblast growth factor that contributes to the characteristic reactive fibrosis associated with this unique tumour.

44: Semin Oncol 1997 Oct;24(5):515-25

Immunohistochemical and molecular genetic approaches to soft tissue tumor diagnosis: a primer.

Hibshoosh H, Lattes R

Department of Pathology, College of Physicians and Surgeons Columbia University New York, NY 10032, USA.

During the past two decades we have witnessed the identification of an expanding list of immunohistochemical and molecular markers linked to histopathologically defined subtypes of tumors. These markers offer new insights and approaches to the classification of tumors with important prognostic and/or therapeutic implications. We review the potentially diagnostic immunohistochemical and molecular markers of soft tissue tumors (STTs). The immunohistochemical markers reviewed include vimentin, cytokeratin, desmin, HHF35, S100, myoD1, alpha1-antitrypsin, vascular markers (factor VIII, CD31, CD34), MIC2, and others. The potentially diagnostic chromosomal translocations and associated genes identified in STT include Ewing’s/PNET t(11;22)(q24;q12)(FLI1;EWS), t(21;22)(q22;q12)(ERG; EWS); t(7;22)(p22;q12)(ETV1;EWS); desmoplastic small round cell tumor t(11;22)(p13;q12)(WT1;EWS); extraskeletal myxoid chondrosarcoma t(9;22)(q22;q12) (TEC(CHN);EWS); malignant ectomesenchymoma t(11;22)(q24;q12)(FLI1;EWS); alveolar rhabdomyosarcoma t(2;13)(q35;q14)(PAX-3;FKHR); t(1;13) (p36;q14)(PAX-7;FKHR); myxoid and round cell liposarcoma t(12;16)(q13;p11)(CHOP;TLS(FUS)); synovial sarcoma t(X;18)(p11;q11)(SSX1&2;SYT), and others. The nature, utility, and limitations of these markers in diagnostic settings are explored.

45: J Urol 1997 Oct;158(4):1506-9

Urogenital involvement by desmoplastic small round-cell tumor.

Furman J, Murphy WM, Wajsman Z, Berry AD 3^rd

Department of Pathology and Laboratory Medicine, University of Florida College of Medicine, Gainesville 32610, USA.

PURPOSE: We strove to characterize the clinicopathologic features of a rare malignant tumor involving the urogenital system. MATERIALS AND METHODS: Of 109 reported cases of desmoplastic small round-cell tumor, 25 have involved organs ordinarily evaluated and treated by urologists. Experience based on these cases plus 2 from our files forms the basis of this review. RESULTS: The term desmoplastic small round-cell tumor has been applied to a rare, highly malignant neoplasm that occurs most often in the abdominal cavity and is described in the nonurological literature. This cancer has distinctive histological, immunohistochemical and ultrastructural features. Several reports suggest a characteristic genetic abnormality. All reported patients who have tumors involving the genitourinary structures have been treated with chemotherapy, but prognosis has been poor. CONCLUSIONS: The literature on desmoplastic small round-cell tumor indicates that a significant percentage of these rare malignancies involve genitourinary organs. In most cases, tumors have been unresectable surgically and treatment has been multidrug chemotherapy. Response to treatment has been poor, with only 3 of 25 determinate cases free of disease when reported.

Review of reported cases

46: Virchows Arch 1997 Aug;431(2):83-94

The role of cytogenetics in the classification of soft tissue tumours.

Dei Tos AP, Dal Cin P

Department of Pathology, City Hospital, Treviso, Italy.

Soft tissue tumours represent a heterogeneous group of mesenchymal lesions, and their classification is the subject of continuous debate. Chromosome analysis, molecular cytogenetics and molecular assays may become increasingly useful in diagnosis, and this review summarises advances in the cytogenetic characterisation and classification of soft tissue tumours. Among the group of fibrous lesions, superficial fibromatosis exhibits trisomy 8. This genomic change is also observed in desmoid fibromatosis in association with trisomy 20. Trisomy 11 is the most frequently observed chromosomal aberration in congenital fibrosarcoma. Dermatofibrosarcoma protuberans and giant cell fibroblastoma share a translocation t(17;22), which supports the concept of the existence of a common differentiation pathway. Adipose tissue tumours is the group in which integration of genetics and pathology has been most fruitful. Ordinary lipomas cytogenetically show an abnormal karyotype in about half the cases. Genomic changes of the 11q13 region are observed in hibernoma. Lipoblastoma exhibits a specific 8q rearrangement in 8q11-q13. Loss of material from the region 16q13-qter and 13q deletions are observed in spindle cell/pleomorphic lipomas. The well-differentiated liposarcoma/atypical lipoma group is characterised karyotypically by the presence of one extra ring and/or extra giant chromosome marker. Myxoid and round cell liposarcoma share the same characteristic chromosome change: t(12;16)(q13;p11) in most cases. In the group of smooth muscle lesions most data are derived from uterine leiomyomas, which can be subclassified cytogenetically into seven different types. Half of all leiomyomas are chromosomally normal; the other half have one of six possible consistent chromosome changes. Alveolar rhabdomyosarcoma is characterised cytogenetically by two variant translocations t(2;13)(q35;q14) and t(1;13)(p36;q14). Among tenosynovial tumours, the localised type of giant cell tumour of tendon sheath exhibits two different karyotypic changes. One involves 1p11 in a translocation with chromosome 2 or with another chromosome. A second type involves 16q24. Synovial sarcoma is characterised cytogenetically by a translocation occurring between chromosome 18 and presumably two adjacent loci on the X chromosome. In neural tumours, abnormalities of chromosome 22 have been reported in benign schwannomas and perineuriomas. Malignant peripheral nerve sheath tumours exist in two main forms: sporadic and associated with the NF-1 syndrome. Karyotypes are very complex, but chromosomes 17q and 22q are very often involved. Clear cell sarcoma is characterised cytogenetically and molecularly by a translocation t(12;22)(q13;q12). The Ewing’s sarcoma/peripheral neuroectodermal tumour category shows a central karyotypic anomaly represented by the translocation t(11;22). The two variants t(21;22) and t(7;22) are found in some cases. Among cartilaginous lesion, the most frequently described anomaly is the t(9;22)(q22;q12) in extraskeletal myxoid chondrosarcoma. Intra-abdominal desmoplastic small round cell tumour is characterised by a t(11;22)(p13;q12).

47: Klin Padiatr 1997 Jul-Aug;209(4):156-64

Assessment of molecular genetic detection of chromosome translocations in the differential diagnosis of pediatric sarcomas.

Dockhorn-Dworniczak B, Schafer KL, Blasius S, Christiansen H, Koscielniak E, Ritter J, Winkelmann W, Jurgens H, Bocker W

Gerhard-Domagk-Institut fur Pathologie, Munster.

BACKGROUND: Recent studies have shown that many types of soft-tissue sarcomas are characterized by specific chromosomal translocations, which are likely to be of etiologic significance. In order to evaluate their diagnostic impact, a panel of 129 sarcomas comprising 78 Ewing’s tumors (ET), 19 rhabdomyosarcomas (RMS), 20 neuroblastomas (NB), 9 synovialsarcomas, 2 esthesioneuroblastomas, and 1 desmoplastic small-round-cell tumor (DSRCT) were analysed for the occurrence of the major recurrent translocations, such as t(11;22)(q24;q12), t(21;22)(q22;q12), t(11;22)(p13;q12), t(2;13)(q35;q14), t(1;13)(p36;q14), and t(X;18)(p11;q11). METHODS: Nitrogen-frozen tissue material was analysed by means of Reverse Transcription followed by PCR (Polymerase-Chain Reaction) and nested PCR (RT-PCR). Specificity of the PCR products obtained was confirmed by non-isotopic Southern-Blot analysis with gene-specific probes and/or automated direct sequence analysis. RESULTS: 75 ETs have been shown to carry either a t(11;22) or t(21;22) translocation by identification of chimeric EWS-FLI-1 or EWS-ERG gene-fusion transcripts respectively. 3 ETs were lacking EWS/FLI-1 or EWS-ERG fusion products. 2 of these tumors were shown on review to have unusual morphological features for ETs. 8/19 RMS were initially diagnosed as alveolar RMS. These tumours were shown to carry either a t(2;13) translocation exhibiting chimeric PAX3-FKHR fusion transcripts or a t(1;13) translocation with PAX7-FKHR chimeric gene products. One RMS of the embryonal group also carried a t(1;13) translocation. Reevaluation demonstrated a partly alveolar morphology. In 8/9 synovial sarcomas a t(X;18) translocation was identified. Expression of a EWS-WTI gene-fusion product associated with a t(11;22) translocation was found in the DSRCT. None of these rearrangements were detected in the NBs and 2 esthesioneuroblastomas. CONCLUSIONS: Our results support the concept that the major recurrent translocations are histogenetically specific for a subset of sarcomas. Thus, the detection of tumor type-specific translocations represents an extremely useful diagnostic modality as an adjunct to surgical pathology.

48: Singapore Med J 1997 Apr;38(4):169-71

Intraabdominal desmoplastic small round cell tumour in an 11-year-old boy.

Ariffin H, Ariffin WA, Wong KT, Ramanujam TM, Lin HP

Department of Paediatrics, University of Malaya, Kuala Lumpur, Malaysia.

A case of desmoplastic small round cell tumour (DSRCT) is presented. This aggressive and rare neoplasm predominantly affects males and is almost exclusively intraabdominal in location. It is unique in that neural, mesenchymal and epithelial markers are co-expressed. Despite multi-modal therapy, the prognosis is extremely poor. The present report details the clinical features and typical pathological findings of DSRCT in an 11-year-old boy, who succumbed to the disease 16 months after diagnosis despite multiple chemotherapeutic regimes.

49: Histopathology 1997 Apr;30(4):312-4

Immunohistochemical detection of the Wilms’ tumour gene WT1 in desmoplastic small round cell tumour.

Charles AK, Moore IE, Berry PJ

Department of Pathology, St Michael’s Hospital, Bristol, UK.

The desmoplastic small round cell tumour (DSRCT) is a rare, highly malignant neoplasm usually presenting in the abdomen of adolescent males. A characteristic translocation between the Ewing’s sarcoma gene on chromosome 22 and the Wilms’ tumour gene WT1 on chromosome 11 has been described, producing a fusion gene with expression of the DNA binding area of WT1. Some Wilms’ tumour antibodies recognize epitopes of this part of the WT1 protein. All four cases of DSRCT examined showed strong staining of the tumours with an anti-WT1 antibody, suggesting this may be useful in the diagnosis of these tumours.

50: Hum Pathol 1997 Apr;28(4):502-9

An intra-abdominal small round cell neoplasm with features of primitive neuroectodermal and desmoplastic round cell tumor and a EWS/FLI-1 fusion transcript.

Katz RL, Quezado M, Senderowicz AM, Villalba L, Laskin WB, Tsokos M

Department of Anatomic Pathology, National Naval Medical Center, Bethesda, MD, USA.

We report an intra-abdominal round cell tumor in a young man which exhibited the light and electron microscopic appearance of a peripheral primitive neuroectodermal tumor (PNET), in addition to the clinical and topographic characteristics, desmoplasia and a complex immunophenotypic profile of the intra-abdominal desmoplastic round cell tumor (DSRCT). Reverse transcription polymerase chain reaction revealed a EWS/FLI-1 fusion transcript as in PNET/Ewing’s sarcoma, instead of the EWS/WT1 transcript of DSRCT. The tumor was also strongly positive for the mic2 protein. This is a unique case of a hybrid tumor arising in the peritoneal cavity of a young male. The existence of such a hybrid tumor in this location suggests that DSRCT and PNET may be related and possibly share a common histogenesis.

51: Pediatr Nephrol 1997 Apr;11(2):208-9

Malignancy-associated membranoproliferative glomerulonephritis.

Rahman RC, Pollono D, Drut R, Spizzirri FD

Department of Nephrology, Hospital de Ninos, Superiora Sor Maria Ludovica, La Plata, Argentina.

An 11-year-old girl with an abdominal desmoplastic round cell tumor, treated with chemotherapy, presented with gross hematuria and proteinuria. Renal biopsy revealed type I membranoproliferative glomerulonephritis (MPGN). The association of a malignant tumor and MPGN is extremely unusual in children, and the pathogenesis of the renal lesion under these circumstances is unknown.

52: J Pediatr Hematol Oncol 1997 Mar-Apr;19(2):172-5

Disseminated intrathoracic desmoplastic small round-cell tumor: a case report.

Venkateswaran L, Jenkins JJ, Kaste SC, Shurtleff SA, Downing JR, Pappo AS

Department of Hematology-Oncology, St. Jude Children’s Research Hospital, Memphis, TN 38105-2794, USA.

PURPOSE: Recently recognized as a distinct clinicopathologic entity, desmoplastic small round-cell tumors typically affect young men. These aggressive tumors usually arise in the abdomen; other sites of primary disease have been described only rarely. We report the case of an extraabdominal primary tumor with widespread dissemination, including the subcutaneous tissue, a previously unrecognized metastatic site. PATIENT AND METHODS: We describe the case of a 16-year-old boy with a primary extraabdominal metastatic desmoplastic small round-cell tumor. RESULTS: Our patient had a primary intrathoracic desmoplastic small round-cell tumor and widespread dissemination involving the subcutaneous tissue, kidney, liver, bone, and lymph nodes. Histopathologic analysis found intense desmoplasia and polyphenotypic expression of neural, muscle, and epithelial markers. Reverse transcriptase-polymerase chain reaction analysis of fresh tumor tissue confirmed the characteristic EWS-WT1 transcript. CONCLUSIONS: Broader than originally anticipated, the clinical spectrum of desmoplastic small round-cell tumors continues to evolve. Primary intrathoracic tumors with soft-tissue dissemination and polyphenotypic expression should prompt suspicion of this malignancy. Molecular analysis of fresh tumor tissue is an important adjunct to diagnosing this rare neoplasm.

53: Genes Chromosomes Cancer 1997 Mar;18(3):232-9

LINE-I element insertion at the t(11;22) translocation breakpoint of a desmoplastic small round cell tumor.

Liu J, Nau MM, Zucman-Rossi J, Powell JI, Allegra CJ, Wright JJ

NCI-Navy Medical Oncology Branch, National Cancer Institute, Bethesda, Maryland, USA.

A t(11;22)(p13;p12) chromosomal translocation, juxtaposing the Wilms’ tumor (WT1) and Ewing’s sarcoma (EWS) genes, is the cytogenetic hallmark of desmoplastic small round cell tumor (DSRCT), a primitive multiphenotypic sarcoma arising in serosal tissues. Chimeric transcripts generated by this rearrangement encode an aberrant transcription factor that fuses the 5’ region of EWS with a 3’ WT1 segment. We describe the insertion of a LINE-I DNA mobile genetic element at the genomic breakpoint of a DSRCT chromosomal translocation. A 480 bp heterologous DNA segment with homology to the LINE-I DNA consensus sequence was located between EWS intron 8 and WT1 exon 8 in the productively rearranged allele. Sequence homology corresponded to the LINE-I ORF-2, which encodes a protein with reverse-transcriptase activity. The heterologous inserted fragment was not evident in the germline of normal tissue from the patient, suggesting that transposition occurred in somatic cells, possibly during the process of chromosomal rearrangement. This case represents the first example of LINE-I DNA transposition at the fusion site of a tumor-associated chromosomal rearrangement.

54: Am J Surg Pathol 1997 Feb;21(2):219-25

Desmoplastic small round cell tumors of the paratesticular region. A report of six cases.

Cummings OW, Ulbright TM, Young RH, Del Tos AP, Fletcher CD, Hull MT

Department of Pathology and Laboratory Medicine, Indiana University School of Medicine, Indianapolis, USA.

Desmoplastic small round cell tumor (DSRCT) typically occurs in the abdomen but may also present at other sites. We report six cases of paratesticular DSRCT. The patients, who ranged in age from 17 to 37 (mean, 28) years, presented with a scrotal mass (five cases) or testicular pain (one case). Grossly, the tumors were white to tan and firm. Typically, they involved the paratesticular soft tissue, serosal surfaces and the epididymis near the junction with the rete testis. Microscopically, the tumors consisted of nests of mitotically active "small blue cells" with scant cytoplasm embedded in a densely fibrotic stroma. Two tumors showed focal tubule formation; one of these also formed rosettes. The tumors exhibited the typical immunophenotype of DSRCT (positivity for keratin, vimentin, desmin, and neuron-specific enolase but nonreactivity with HBA-71 and anti-S-100). Four tumors metastasized to lymph nodes (retroperitoneal, cervical, and two unspecified); pulmonary metastases occurred in one of these cases and in one patient without lymph node metastases. One of the above patients treated with chemotherapy, died of disease at 16 months. The patients with pulmonary metastases (one of whom also had lymph node metastases) were treated with aggressive chemotherapy and are alive and apparently disease-free at 2.5 and 3 years, respectively. Three of the six patients, two of whom had known metastases, were lost to follow-up. The DSRCT of the paratestis has histologic and immunohistochemical features identical to its abdominal counterpart and must be differentiated from other "small blue cell" tumors of the paratesticular region.

55: Curr Top Microbiol Immunol 1997;220:151-62

Chromosome translocation-mediated conversion of a tumor suppressor gene into a dominant oncogene: fusion of EWS1 to WT1 in desmoplastic small round cell tumors.

Rauscher FJ 3^rd

56: Hum Mutat 1997;9(3):209-25

A clinical overview of WT1 gene mutations.

Little M, Wells C

Centre for Molecular and Cellular Biology, University of Queensland, St. Lucia, Australia.

Mutations in the WT1 gene were anticipated to explain the genetic basis of the childhood kidney cancer, Wilms tumour (WT). Six years on, we review 100 reports of intragenic WT1 mutations and examine the accompanying clinical phenotypes. While only 5% of sporadic Wilms’ tumours have intragenic WT1 mutations, > 90% of patients with the Denys-Drash syndrome (renal nephropathy, gonadal anomaly, predisposition to WT) carry constitutional intragenic WT1 mutations. WT1 mutations have also been reported in juvenile granulosa cell tumour, non-asbestos related mesothelioma, desmoplastic small round cell tumour and, most recently, acute myeloid leukemia.

57: Ultrastruct Pathol 1997 Jan-Feb;21(1):1-31

Ultrastructural pathology of glial brain tumors revisited: a review.

Liberski PP, Kordek R

Department of Oncology, Medical Academy Lodz, Poland.

The ultrastructural pathology of primary brain tumors of glial origin is examined. These are divided into two major groups. The first category comprises astrocytoma with the variants: fibrillary, protoplasmic, gemistocytic, and anaplastic. These are biologically aggressive tumors of a relatively high proliferative potential and include a substantial proportion of cases that transform into the most malignant secondary glioblastoma. The second category, comprised of rather benign tumors of a limited proliferative capacity and a reasonable good prognosis, includes such clinico-pathological entities as pilocytic astrocytoma, pleomorphic xanthoastrocytoma, and subependymal giant cell astrocytoma of tuberous sclerosis. There is no ultrastructural feature, however, which makes it possible to discriminate between major subclasses of astrocytes; but secondary glioblastoma cells, while still retaining the stigmata of neoplastic astrocytes, are characterized by nuclei that seem to be more indented, cisterns of the endoplastic reticulum may be distended, and intranuclear pseudoinclusions are frequently observed. Primary glioblastoma, which probably originates de novo, is characterized by poorly differentiated cells with a paucity of subcellular organelles and no obvious features of astrocytic origin. Granular cell tumor also belongs to neoplasms of astrocytic lineage and the hallmark of this entity is a cell characterized by the presence of numerous membrane-bound, electron-dense autophagic vacuoles. Its malignant analogue is the granular cell glioblastoma. Two subtypes of granular cell glioblastoma have been distinguished. The first is characterized by the presence of numerous granular, electron-dense bodies which correspond to autophagic vacuoles. The second type is characterized by numerous electron-dense, amorphous masses within cellular processes. These electron-dense inclusions are virtually indistinguishable from minute Rosenthal fibers. The pilocytic astrocytoma is virtually indistinguishable at the ultrastructural level from fibrillary astrocytomas but cells tend to be more elongated. Besides Rosenthal fibers, two types of distinctive structures are relatively common in pilocytic astrocytomas: eosinophilic hyaline droplets and round granular bodies, which are composed of large aggregates of electron-dense secondary lysosomes or small electron-dense bodies, respectively. Pleomorphic xanthoastrocytoma is characterized by astrocytes surrounded by basal membranes. It belongs to a peculiar category of astrocytic "desmoplastic" brain tumors occurring in younger patients, the common denominator for which is the presence of basal lamina. The last category in this group is subependymal giant cell astrocytoma, a tumor of bivalent (glial and neuronal) differentiation, the cells of which are characterized by the presence of peculiar crystalloids. The hallmark of oligodendroglioma is the presence of concentric arrays of membranes (so-called membrane laminations, whorls, or scrolls). A fragment of the cytoplasm sequestrated within a particular whorl may contain mitochondria, lysosomes, or abundant glycogen granules. Ependymomas are characterized by a florid picture dominated by the presence of microlumina, cilia with basal bodies (blepharoplasts), microvilli, and long, interdigitating intercellular junctions of the zonulae adherentiae type. Ganglioglioma, the last category covered by this review, is a mixed glio-neuronal tumor. While glial cells are indistinguishable from their counterparts encountered elsewhere (mostly pilocytic astrocytes), the ganglion cells are characterized by abundant intracytoplasmic dense-core vesicles, absence of intermediate filaments, and numerous microtubules. Occasionally a close apposition of ganglion cells and Rosenthal fibers is seen. Dense-core vesicles are pleomorphic and ranged in a diameter from small synaptic vesicles to large lysosome-like neurosecretory granules.

58: Br J Cancer 1997;75(1):76-8

Ca125 and neuron-specific enolase (NSE) as tumour markers for intra-abdominal desmoplastic small round-cell tumours.

Fizazi K, Farhat F, Theodore C, Rixe O, Le Cesne A, Comoy E, Le Chevalier T

Department of Medical Oncology, Institut Gustave-Roussy, Villejuif, France.

Seven consecutive patients with intra-abdominal desmoplastic small round-cell tumours were screened at presentation for carcinoembryonic antigen (CEA), Ca19-9, Ca15-3, Ca125, alpha-fetoprotein (AFP), human chorionic gonadotrophin (hCG) and neuron-specific enolase (NSE). Initially elevated tumour markers were used to monitor therapy and follow-up. Tumour marker assays were all in the normal range, with the exception of Ca125 and NSE. The Ca125 level was initially high in six of the seven patients (86%) with a median value of 200 U ml-1 and a range of 22-735 U ml-1. The NSE value was elevated before therapy in three of the five patients (60%) for whom assay results were available, with a median of 19 ng ml-1 and a range of 6.8-37.5 ng ml-1 . Ca1 25 normalized in five out of six cases and NSE always normalized during chemotherapy, but neither of these two tumour markers correlated specifically with response, as only one patient experienced a partial response, five tumour stabilization and the remaining patient tumour progression. At progression, Ca125 was again elevated in two out of four cases several weeks before clinical relapse and NSE in only one out of three cases. Ca125 and NSE are frequently raised in the serum of patients with intra-abdominal desmoplastic small round-cell tumours before therapy, but are not reliable monitors of the course of the disease. However, normalization is frequently associated with an improvement of symptoms or a moderate clinical response.

59: J Pathol 1996 Dec;180(4):462

Specificity of the EWS/WT1 gene fusion for desmoplastic small round cell tumour.

Ladanyi M, Gerald WL

60: Med Pediatr Oncol 1996 Nov;27(5):434-9

Fusion of the EWS1 and WT1 genes as a result of the t(11;22)(p13;q12) translocation in desmoplastic small round cell tumors.

Benjamin LE, Fredericks WJ, Barr FG, Rauscher FJ 3^rd

Wistar Institute, Philadelphia, PA 19104, USA.

The isolation and molecular analysis of genes which cause and/or predispose to Wilms’ tumor have yielded fascinating insights into the role of tissue-specific gene regulation in both development and disease processes. Analysis of the WT1 transcription factor has clearly established its role in Wilms’ tumorigenesis and a broader role in both urogenital organogenesis and mesenchymal cell differentiation events. Clearly, loss of function mutations in WT1 is correlated with aberrant function as a regulator of gene expression, ultimately resulting in neoplastic transformation in the developing kidney. A question we have pursued is whether alterations of WT1 structure and/or function can be associated with other types of malignancies, possibly reflecting WT1’s broader role in mesenchymal differentiation. To this end, we have analyzed a rare solid tumor designated Intra-Abdominal Desmoplastic Small Round Cell Sarcoma (IADSRCT) which often displays a recurrent chromosomal translocation t(11;22)(p13;q12) involving the WT1 genomic locus. We have shown that the EWS1 gene fron chromosome 22q12 is fused to the WT1 gene in IADSRCT and that a fusion protein is produced which functions as a potent activator of transcription. Our results suggest that WT1 has sustained a gain-of function alteration as a results of this fusion and that the fusion gene functions as a dominant oncogene in this disease. Thus, the WT1 locus may be the target for both gain- and loss-of-function mutations resulting in different disease outcomes. A summary of our ongoing analysis of the EWS-WT1 fusion gene is presented.

61: J Biol Chem 1996 Aug 9;271(32):19304-9

The IGF-I receptor gene promoter is a molecular target for the Ewing’s sarcoma-Wilms’ tumor 1 fusion protein.

Karnieli E, Werner H, Rauscher FJ 3^rd, Benjamin LE, LeRoith D

Section on Molecular and Cellular Physiology, Diabetes Branch, NIDDK, National Institutes of Health, Bethesda, Maryland 20892, USA.

Desmoplastic small round cell tumor (DSRCT) is an abdominal malignancy in children which is characterized by a recurrent chromosomal translocation, t(11;22)(p13;q12). This rearrangement results in the fusion of the ubiquitously expressed EWS1 gene to the Wilms’ tumor suppressor (WT1) gene. The chimeric protein contains the N-terminal domain of EWS1 fused to the DNA-binding domain of WT1, including zinc fingers 2-4. Because WT1 has been shown previously to bind and repress the insulin-like growth factor I (IGF-I-R) promoter, we investigated whether this promoter is, in addition, a target for the aberrant EWS/WT1 transcription factor. EWS/WT1 activated the IGF-I-R promoter approximately 340%, whereas a fusion protein containing a three-amino acid insert (KTS) between zinc fingers 3 and 4 had no effect. On the other hand, expression vectors encoding either WT1 or EWS1 reduced the activity of the promoter to 46 and 58% of control values, respectively. Results of gel shift assays indicate that the binding affinity of EWS/WT1 to a fragment of the 5’-flanking region of the receptor promoter was higher than the affinity of WT1 itself. Consistent with the results of functional assays, the binding of EWS/WT1(+KTS) was significantly reduced. Due to the central role of the IGF-I-R in tumorigenesis, activation of the receptor promoter by EWS/WT1 may constitute a potential mechanism for the etiology and/or progression of DSRCT.

62: Pathol Res Pract 1996 Aug;192(8):796-807

Malignant rhabdoid tumor in adults—heterogenous tumors with a unique morphological phenotype.

Leong FJ, Leong AS

Division of Tissue Pathology, University of Adelaide, South Australia.

Five cases of malignant rhabdoid tumors in adult patients are described. The tumors were characterized by sheets of poorly cohesive cells with distinctive hyaline cytoplasmic inclusions and eccentrically placed large vesicular nuclei with prominent nucleoli. A variety of lineage differentiation was shown by immunohistochemistry and electron microscopy, the lesions representing leiomyosarcoma, gastric carcinoma, epithelioid sarcoma, Merkel cell carcinoma and desmoplastic small round cell tumor. Previously reported cases of rhabdoid tumors in adults support the contention that such tumors, although of distinctive morphologic phenotype, are of heterogenous lineage differentiation, and do not represent a distinct clinicopathologic entity.

63: Semin Diagn Pathol 1996 Aug;13(3):204-12

Desmoplastic small round cell tumor.

Leuschner I, Radig K, Harms D

Department of Pediatric Pathology, Kiel Pediatric Tumor Registry, University of Kiel, Germany.

Desmoplastic small round cell tumor is an undifferentiated tumor associated with serosal surfaces, especially the peritoneum. It is found predominantly in adolescents and young adults and is much more common in males than in females. The tumor has a characteristic histology, with extensive stromal tissue around islands of small and undifferentiated cells revealing the desmoplastic appearance. The coexpression of epithelial and mesenchymal antigens distinguishes this entity from other small round and blue cell tumors of this age group. Cytogenetic studies showed a t(11;22) translocation that differs from the Ewing’s tumor translocation and seems to be specific to this entity. The involvement of the WT1 and EWS genes in the translocation makes this tumor an interesting subject for research on histogenesis and differentiation in small round and blue cell tumors.

64: Semin Diagn Pathol 1996 Aug;13(3):184-203

Soft tissue small round cell tumors: morphological parameters.

d’Amore ES, Ninfo V

Istituto di Anatomia Patologica dell’ Universita di Padua, Italy.

Soft tissue small round cell tumors (SRCTs) comprise a heterogeneous group of neoplasms that predominate in childhood and adolescence and share similar morphological features, consisting of dense cellular proliferation of small round cells with a primitive appearance. Rhabdomyosarcomas, peripheral neuroepitheliomas, Ewing’s sarcomas, and lymphomas/leukemias are the prototypic SRCT; other recently described tumors that should be added to the list are the desmoplastic SRCT and the rhabdoid tumor of soft tissues. In addition, several other primary soft tissue neoplasms and metastatic tumors have occasionally been considered in the differential diagnosis of SRCT. The precise identification of a given SRCT is important because of its clinical relevance. However, it may be difficult because the diagnostic criteria are sometimes subtle and several histologic and immunohistochemical features are not specific and/or may be simulated by different tumor types. We discuss the morphological clues that in our opinion are most useful for their diagnosis, the criteria for distinguishing between peripheral neuroepithelioma and Ewing’s sarcoma, and the main diagnostic pitfalls.

65: J Pediatr Hematol Oncol 1996 Aug;18(3):293-8

Desmoplastic small cell tumor: a report of three cases and a review of the literature.

Kretschmar CS, Colbach C, Bhan I, Crombleholme TM

Division of Hematology-Oncology, Department of Pediatrics, Floating Hospital for Children at the New England Medical Center, Boston, Massachusetts 02111, USA.

PURPOSE: Desmoplastic round cell tumor (DSCT) is a highly malignant abdominal tumor first described in 1991, with subsequent cases predominantly noted in pathologic case reports. The authors evaluated response to alternating, intensive chemotherapy in three patients with DSCT, and reviewed the clinical experience with this newly described tumor as reported in the literature. PATIENTS AND METHODS: Three adolescent boys with DSCT were treated intravenously with vincristine 2 mg/m2, doxorubicin 75 mg/m2, cyclophosphamide 1.8 g/m2, alternating with 5-day cycles of etoposide 100 mg/m2/day, ifosfamide 1.8 g/m2/day for a total of 11-15 courses. RESULTS: Each patient showed initial tumor regression during chemotherapy, but developed progressive disease within 8-18 months. One patient subsequently showed a transient response to doxorubicin 45 mg/m2 plus 5-fluorouracil 500-600 mg/m2. All three patients died of disease within 20 months of diagnosis. A comprehensive literature review of clinical data on 101 reported cases of DSCT is presented. The median age was 21 years (range 6-38 years) with 78 male patients and 23 female patients. Ninety-nine cases involved tumor mass in the abdominal-pelvic cavity in proximity to the mesentery. Metastatic seeding to the omentum was most common, followed by spread of disease to liver, distant lymph nodes, lung, and occasionally to scrotum or to ovary. Tumor response to chemotherapy was noted in approximately 50% of 40 patients who received combinations of doxorubicin, cisplatin, cyclophosphamide, etoposide, and/or 5-fluorouracil. Four of 13 patients who received additional radiotherapy were alive at 24-48 months. Median survival was 17 months (range:3-72 months), with only two patients reported disease free beyond 2 years at 40 and 48 months. CONCLUSION: DSRCT should be included in the differential diagnosis of small round cell tumors in children and young adults. Tumor regression has been noted during multiagent chemotherapy, but prolonged survival is rare with current therapies.

66: J Pediatr Hematol Oncol 1996 Aug;18(3):289-92

Intraabdominal desmoplastic small round cell tumor presenting as a gastric mural mass with hepatic metastases.

Murray JC, Minifee PK, Trautwein LM, Hicks MJ, Langston C, Morad AB

Texas Children’s Cancer Center and Hematology Service, Houston, USA.

PURPOSE: An atypical case of childhood intraabdominal desmoplastic small round cell tumor (DSRCT) is presented. PATIENT AND METHODS: An 11-year-old boy presented with progressive nausea and vomiting, abdominal pain, hepatomegaly, and an epigastric mass. Computed tomographic scanning as well as findings at gastroscopy and laparotomy revealed a large gastric mural tumor accompanied by multiple large intrahepatic masses. Histopathologic examination of biopsy samples revealed evidence of a polyphenotypic neoplasm diagnostic of DSRCT. RESULTS: Unlike most reported cases of DSRCT, no evidence of peritoneal involvement or ascites was detected. Despite an excellent initial response to multiagent chemotherapy, the patient eventually died of progressive tumor. CONCLUSIONS: Though the radiographic and surgical findings in DSRCT usually suggest a mesenteric, peritoneal, or retroperitoneal site of tumor origin, this case demonstrates that intraabdominal DSRCT can present with a primary visceral lesion without evidence of peritoneal or mesenteric involvement or ascites. Combination chemotherapy using vincristine, doxorubicin, cyclophosphamide, cisplatin, and 5-fluorouracil may be of some benefit to patients with this rare tumor.

67: Mod Pathol 1996 Jun;9(6):703-9

Intra-abdominal desmoplastic small round-cell tumor: expansion of the pathologic profile.

Dorsey BV, Benjamin LE, Rauscher F 3^rd, Klencke B, Venook AP, Warren RS, Weidner N

Department of Pathology, University of California—San Francisco, 94143, USA.

This report describes an intra-abdominal desmoplastic small round-cell tumor in a 29-year-old man that significantly differed from the classically described appearances of this unique tumor. It showed extensive papillary areas, no necrosis, and very little desmoplasia. The latter was limited, paucicellular, and present in areas separate from the papillary structures. Also, areas of back-to-back, single-cell infiltration, which mimicked lobular breast carcinoma, were present. These epithelial features suggested the diagnosis of adenocarcinoma or peculiar mesothelioma. But, the immunohistochemical features (tumor cells positive for keratin, desmin, and vimentin) were more consistent with an intra-abdominal desmoplastic small round-cell tumor. The diagnosis became clear after application of reverse transcriptase-polymerase chain reaction techniques to formalin-fixed, paraffin-embedded tissue, which showed the presence of a 100-base pair product containing the fusion junction of Ewing’s sarcoma-1 exon 7 to Wilms’ tumor-1 exon 8. This feature is considered unique to intra-abdominal desmoplastic small round-cell tumors. This case illustrates the less common histologic findings that can be found in intra-abdominal desmoplastic small round-cell tumor. This deviation from the classic histologic findings may be an expression of an uncommon morphologic variant and/or partially produced by the effects of prior chemotherapy. In either event, only by illustrating the various histologic appearances of intra-abdominal desmoplastic small round-cell tumor are the chances increased for the accurate diagnosis of this aggressive neoplasm with a poor prognosis.

68: J Clin Oncol 1996 May;14(5):1526-31

Desmoplastic small round-cell tumor: prolonged progression-free survival with aggressive multimodality therapy.

Kushner BH, LaQuaglia MP, Wollner N, Meyers PA, Lindsley KL, Ghavimi F, Merchant TE, Boulad F, Cheung NK, Bonilla MA, Crouch G, Kelleher JF Jr, Steinherz PG, Gerald WL

Department of Pathology, Memorial Sloan-Kettering Cancer Center, New York, NY 10021, USA.

PURPOSE: To test intensive alkylator-based therapy in desmoplastic small round-cell tumor (DSRCT). PATIENTS AND METHODS: Patients received the P6 protocol, which has seven courses of chemotherapy. Courses 1, 2, 3, and 6 included cyclophosphamide 4,200 mg/m2, doxorubicin 75 mg/m2, and vincristine (HD-CAV). Courses 4, 5, and 7 consisted of ifosfamide 9 g/m2 and etoposide 500 mg/m2 for previously untreated patients, or ifosfamide 12 g/m2 and etoposide 1,000 mg/m2 for previously treated patients. Courses started after neutrophil counts reached 500/microL and platelet counts reached 100,000/microL. Tumor resection was attempted. Post-P6 treatment options included radiotherapy and a myeloablative regimen of thiotepa (900 mg/m2) plus carboplatin (1,500 mg/m2), with stem-cell rescue. RESULTS: Ten previously untreated and two previously treated patients have completed therapy. The male-to-female ratio was 11:1. Ages were 7 to 22 years (median, 14). The largest masses were infradiaphragmatic (n = 11) or intrathoracic (n = 1). Other findings included serosal implants (n = 11), regional lymph node invasion (n = 8), ascites or pleural effusion (n = 7), and metastases to liver (n = 5), lungs (n = 4), distant lymph nodes (n = 3), spleen (n = 2), and skeleton (n = 2). Tumors uniformly responded to HD-CAV, but there were no complete pathologic responses. One patient died at 1 month from tumor-related Budd-Chiari syndrome. Of seven patients who achieved a complete remission (CR), five remain in CR 9, 12, 13, 33, and 38 months from the start of P6, one patient died of infection at 12 months (autopsy-confirmed CR), and one patient relapsed 4 months off therapy. Of four patients who achieved a partial remission (PR), one remains progression-free at 34 months and three developed progressive disease. Five patients received local radiotherapy: three were not assessable for response, but in two patients, antitumor effect was evident. Four patients received thiotepa/carboplatin: two were in CR and remain so, and two patients had measurable disease that did not respond. CONCLUSION: For control of DSRCT, our experience supports intensive use of HD-CAV, aggressive surgery to resect visible disease, radiotherapy to high-risk sites, and myeloablative chemotherapy with stem-cell rescue in selected cases.

69: Pathol Int 1996 Apr;46(4):281-5

Postmenopausal intra-abdominal desmoplastic small cell tumor.

Fukunaga M, Endo Y, Takaki K, Ishikawa E, Ushigome S

Department of Pathology, Jikei University School of Medicine, Tokyo, Japan.

Intra-abdominal desmoplastic small cell tumor (DSCT) usually occurs in infants and young male adults. A case of DSCT occurring in a 60 year old female is described. No other apparent primary origin was detected. A mesocolon tumor, measuring 23 x 12 x 10 cm, was composed predominantly of round to spindle cells which showed epithelioid- and focally sarcomatous arrangements. Immunohistochemically, the tumor cells showed perinuclear dot-like staining of CAM5.2, many cells expressed HHF35, and some cells contained vimentin, epithelial membrane antigen, desmin, alpha-smooth muscle actin, neuron-specific enolase, or Leu 7. Electron microscopic examination showed that the tumor cells had mesenchymal-fibroblastic features. The tumor had an aneuploid DNA content with high S-phase fraction. The patient, who was treated with adjuvant chemotherapy, was alive, having had three recurrences in 36 months. In the second and third recurrent lesions, increased cellular atypia and fascicular arrangements of spindle cells were observed. DSCT should be included in differential diagnoses of post-menopausal pelvic tumors which show light-microscopically and immunohistochemically divergent phenotypes.

70: Cancer 1996 Apr 1;77(7):1363-6

Desmoplastic small round cell tumors: results of a four-drug chemotherapy regimen in five adult patients.

Farhat F, Culine S, Lhomme C, Duvillard P, Soulie P, Michel G, Terrier-Lacombe

MJ, Theodore C, Schreinerova M, Droz JP

Department of Medicine, Institut Gustave Roussy, Villejuif, France.

BACKGROUND. Desmoplastic small round-cell tumor has been identified as a neoplasm with multidirectional immunohistochemical, and molecular features of this tumor sets it apart as a pathologic entity. The optimal treatment remains to be determined. METHODS. Five adult patients were treated according to a uniform first-line chemotherapy program including cisplatin, etoposide, cyclophosphamide, and either doxorubicin or epirubicin. Chemotherapy was delivered after initial surgery in the four patients with intra-abdominal presentation, and at relapse in the fifth patient who had a paratesticular primary tumor. RESULTS. All 4 patients with intra-abdominal disease experienced stability lasting from 4 to 9 months. Only one objective persistent complete response was observed; this was in the patient with a paratesticular primary. No salvage treatment was active in the other four patients who died of progressive disease. CONCLUSIONS. Our experience to a certain degree of chemosensitivity for desmoplastic small round-cell tumors. Despite aggressive treatments, survival rates remain disappointing. Other therapeutic modalities are needed to improve these results.

71: Am J Surg Pathol 1996 Apr;20(4):406-12

Detection of the EWS/WT1 gene fusion by reverse transcriptase-polymerase chain reaction in the diagnosis of intra-abdominal desmoplastic small round cell tumor.

Argatoff LH, O’Connell JX, Mathers JA, Gilks CB, Sorensen PH

Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, Canada.

We report two cases of intra-abdominal desmoplastic small round cell tumor with characteristic clinical, histological, immunohistochemical, and ultrastructural features. Fusion of the EWS gene on chromosome 22 and the WT1 gene on chromosome 11, resulting from the chromosomal translocation t(11;22)(p13;q12), was detected by reverse transcriptase polymerase chain reaction (RT-PCR) in both cases. This translocation has been previously reported in this type of tumor using either cytogenetic or molecular biological techniques. Tumor tissue from both cases revealed no chimeric fusion transcripts characteristic of the Ewing sarcoma family of peripheral primitive neuroectodermal tumors or of alveolar rhabdomyosarcoma, two tumors in the differential diagnosis of intra-abdominal desmoplastic small round cell tumor. This report demonstrates the utility of molecular studies as an adjunct in the diagnosis of this rare and aggressive tumor. 

72: Oncogene 1996 Jan 4;12(1):159-67

The EWS-ATF-1 gene involved in malignant melanoma of soft parts with t(12;22) chromosome translocation, encodes a constitutive transcriptional activator.

Fujimura Y, Ohno T, Siddique H, Lee L, Rao VN, Reddy ES

Department of Microbiology and Immunology, Jefferson Cancer Institute, Philadelphia, PA 19107-5541, USA.

Molecular characterization of malignant melanoma of soft parts or soft tissue clear cell sarcoma which shares t(12;22) chromosome translocation revealed fusion of EWS with a transcriptional factor gene ATF-1. The EWS gene, which encodes an RNA binding protein, was also shown to be involved in Ewing sarcoma, related primitive neuroectodermal tumors and desmoplastic small round cell tumors. In order to understand the functional role of EWS-ATF-1 chimeric protein in human solid tumors, we have cloned the aberrant human ATF-1 (EWS-ATF-1) cDNA and studied its DNA binding, transcriptional activation properties and compared with normal ATF-1 protein. Our results demonstrate that EWS-ATF-1 binds weakly to DNA in vitro but functions as an efficient constitutive transcriptional activator unlike the normal ATF-1 which needs to be induced with cAMP. Deletion analysis revealed that EWS-fusion domain functions as a regulatory domain for the transcriptional activation properties of EWS-ATF-1 chimeric protein. Deletion of leucine zipper domain results in a loss of transcriptional activation of EWS-ATF-1 chimeric protein suggesting that protein-protein interaction play a role in the transcriptional activation properties of EWS-ATF-1. We demonstrate that EWS-fusion domain negatively regulates the DNA binding activity of EWS-ATF-1 chimeric protein. Therefore replacement of part of the amino-terminal kinase regulatory domain of ATF-1 protein with EWS regulatory domain results in an altered DNA binding, protein-protein interactions and transcriptional activation properties of EWS-ATF-1 causing deregulated gene expression which may be responsible for the genesis of t(12;22) chromosome translocation-bearing human solid tumors. Targeting the transcriptional cofactors (CBP, etc) by EWS-fusion proteins could be one of the mechanisms of activation of EWS-fusion proteins in human neoplasia.

73: Pediatr Hematol Oncol 1996 Jan-Feb;13(1):95-9

Intra-abdominal desmoplastic small round cell tumor in children: a clinicopathologic study.

Basade MM, Vege DS, Nair CN, Kurkure PA, Advani SH

Department of Medical Oncology, Tata Memorial Hospital, Parel, Bombay, India.

Desmoplastic small round cell tumor (RCT) is a relatively newly recognized neoplasm. It has a very distinct morphologic and high-grade polyphenotypic expression with a very poor prognosis. It is commonly seen in adolescent boys. We describe two cases of intra-abdominal desmoplastic small RCT in young girls (5 and 11 years of age). In both cases, the exact origin of tumor in the abdomen could not be established. Histopathologic examination of the biopsy specimens showed distinct desmoplastic stroma and coexpression of various epithelial, neural, and muscle markers. These two patients were treated primarily by debulking surgery followed by adjuvant chemotherapy (RCT II protocol). One of the two had a stable disease while the other had a progressive disease while on treatment. Thus our findings support the diverse histogenesis of this tumor and its poor prognosis.

75: Am J Surg Pathol 1996 Jan;20(1):112-7

Intracranial desmoplastic small-cell tumor. Report of a case.

Tison V, Cerasoli S, Morigi F, Ladanyi M, Gerald WL, Rosai J

Anatomic Pathology Service, M. Bufalini Hospital, Cesena, Italy.

We report a case of desmoplastic small-cell tumor occurring in the CNS in relation to the tentorium in a 24-year-old man. Morphologically, the neoplasm had the typical appearance of small, round tumor cells of primitive appearance growing as well-defined nests separated by abundant desmoplastic stroma. The diagnosis was confirmed through the demonstration of immunoreactivity for keratin, desmin, and neuron-specific enolase and the detection by Southern blot analysis of a unique gene resulting from the fusion of the WT1 gene in chromosome 11 and the EWS gene in chromosome 22. This is the first documented instance of the occurrence of this tumor type at a distance from a mesothelial-lined surface.

76: Hum Pathol 1995 Dec;26(12):1370-4

EWS and WT-1 gene fusion in desmoplastic small round cell tumor of the abdomen.

Brodie SG, Stocker SJ, Wardlaw JC, Duncan MH, McConnell TS, Feddersen RM, Williams TM

Department of Pathology, University of New Mexico, School of Medicine, Albuquerque 87131, USA.

Chromosome translocations found in neoplasms often result in the creation of hybrid genes encoding chimeric proteins. This case study describes a patient with desmoplastic small round cell tumor (DSRCT) of the abdomen, an aggressive neoplasm characterized by translocation of chromosomes 11 and 22. Southern hybridization showed that the Ewing sarcoma gene (EWS) gene was rearranged in the DSRCT. Reverse transcriptase-polymerase chain reaction analysis of tumor cell RNA revealed that exons 1 to 7 of the EWS gene were joined to exons 8 to 10 of the Wilms’ Tumor-1 (WT-1) gene resulting in the production of a chimeric message. The WT-1 and EWS genes encode DNA and RNA binding proteins involved in Wilms’ tumor and Ewing sarcoma pathogenesis, respectively. The fusion of these two genes in DSRCT results in the production of a putatively oncogenic protein composed of the zinc finger DNA binding domains of WT-1 linked to potential transcriptional regulatory domains of EWS. DNA sequencing revealed the genomic breakpoints of translocation on chromosomes 11 and 22. The genomic breakpoint on chromosome 22 occurred in EWS intron 7 just 2 nucleotides 3’ of exon 7. Polymerase chain reaction-based assays were developed that could detect the fused genes in the DSRCT tumor using either RNA or genomic DNA. The potential diagnostic use of these assays is discussed.

77: Am J Pathol 1995 Dec;147(6):1584-91

Detection of chimeric transcripts in desmoplastic small round cell tumor and related developmental tumors by reverse transcriptase polymerase chain reaction. A specific diagnostic assay.

de Alava E, Ladanyi M, Rosai J, Gerald WL

Department of Pathology, Memorial Sloan-Kettering Cancer Center, New York, New York 10021, USA.

Desmoplastic small round cell tumor is a recently described entity associated with fusion of the EWS and WT1 genes and with expression of a chimeric transcript. To investigate the structure and potential diagnostic utility of the detection of EWS-WT1 chimeric RNA in desmoplastic small round cell tumor, 12 examples of this entity and 49 other tumors that enter in its differential diagnosis were studied by reverse transcriptase polymerase chain reaction for the presence of EWS-WT1, EWS-FLI-1, PAX3-FKHR, and PAX7-FKHR chimeric transcripts. EWS-WT1 was detected in 11 of 12 desmoplastic small round cell tumors but not in any other tumor type studied, including 17 Wilms’ tumors, 10 Ewing’s sarcomas/primitive neuroectodermal tumors, 13 alveolar rhabdomyosarcomas, and 9 embryonal rhabdomyosarcomas. One desmoplastic small round cell tumor was found to have a variant EWS-WT1 chimeric product that included exon 8 of EWS EWS-FLI-1 chimeric RNA was present in all Ewing’s sarcoma/primitive neuroectodermal tumor and not identified in any other tumor types, including desmoplastic small round cell tumor. PAX3/PAX7-FKHR chimeras were present in 9 of 13 alveolar rhabdomyosarcomas but not in any other tumors. Detection of chimeric transcripts by reverse transcriptase polymerase chain reaction is a very specific aid in differential diagnosis of developmental tumors and further establishes desmoplastic small round cell tumor as a distinct entity.

78: Diagn Cytopathol 1995 Nov;13(4):325-9

Biphasic intraabdominal desmoplastic small round cell tumor: fine-needle aspiration cytology findings.

Drut R

Servicio de Patologia, Hospital de Ninos, La Plata, Argentina.

The present report describes the case of a 9-yr-old boy with an abdominal desmoplastic small round cell tumor (DSRCT) which on fine-needle aspiration cytology and histology revealed a biphasic pattern, making initial diagnosis difficult. Epithelial-like clusters of cells and loosely-arranged poorly-differentiated cells with scant cytoplasm associated with cells having a larger nucleus and multinucleated larger cells represented the smears’ counter-part of epithelial clusters and lobules and sarcomatous-like tissue recognized in the histologic sections. Multinucleated cells were common in the sarcomatous-like areas of the tumor. The biphasic pattern was highlighted by immunohistochemistry. Keratin and epithelial membrane antigen stained predominantly or only the epithelial component, while desmin diffusely decorated the sarcomatous areas and the epithelial cells as a paranuclear cytoplasmic dot. Immunosera 013 mainly stained the sarcomatous component.

79: Pediatr Pathol Lab Med 1995 Sep-Oct;15(5):797-803

Intra-abdominal desmoplastic small round cell tumor with extensive extra-abdominal involvement.

Resnick MB, Donovan M

Department of Pathology, Children’s Hospital, Boston, Massachusetts 02115, USA.

Intra-abdominal desmoplastic small round cell tumor (DSRCT) is a recently described, rare neoplasm that usually occurs in male adolescents, has a poor prognosis, and displays a typical clinicopathological profile. This aggressive neoplasm exhibits a predominantly intra-abdominal serosal pattern, with frequent pelvic extension, less frequent retroperitoneal involvement, and rare pulmonary and mediastinal spread. We report on the autopsy findings of a 9-year-old male who presented with a biopsy-proven DSRCT involving the abdomen, retroperitoneum, and scrotum and additional radiologic studies suggesting vertebral, hepatic, and mediastinal involvement. Postmortem examination performed 10 months after presentation confirmed the initial radiologic findings and demonstrated extensive pleural and pulmonary metastases and, for the first time, direct evidence of bone marrow involvement. This tumor exhibited the typical immunophenotype previously reported for DSRCT, namely multidirectional expression of epithelial, neural, and muscular markers.

80: Diagn Mol Pathol 1995 Sep;4(3):162-73

The emerging molecular genetics of sarcoma translocations.

Ladanyi M

Department of Pathology, Memorial Sloan-Kettering Cancer Center, New York 10021, USA.

Many types of sarcomas are characterized by specific chromosomal translocations which are likely to be of etiologic significance. The recent elucidation of the molecular structure of the several of these translocations has revealed some striking similarities. Nearly all appear to result in the production of novel, tumor-specific chimeric transcription factors. Furthermore, six of the translocations, namely the t(11;22), t(21;22), and t(7;22) of Ewing’s sarcoma, the t(12;22) of clear cell sarcoma, the t(12;16) of myxoid liposarcoma, and the t(11;22) of desmoplastic small round cell tumor, achieve this following a peculiar pattern, consisting in the fusion of a gene with an RNA-binding domain (EWS or TLS) with a transcription factor gene (FLI1, ERG, ETV1, ATF-1, CHOP, or WT1). The observation that the different translocation partners of the EWS gene are specifically associated with several distinct types of primitive sarcomas suggests a model in which the translocation partner supplying the DNA-binding domain confers the target specificity of the transcriptional activation mediated by these chimeric proteins, whereas the partner supplying the N-terminal domain and promoter region determines their transactivation potential and expression level. Further analysis of the normal functions and expression patterns of these genes should yield insights into the histogenesis of these different tumor types and into normal tissue development and differentiation. Clinically, our new understanding of the molecular structure of these translocations opens new avenues for molecular diagnosis and investigative therapeutics.

81: Int J Cancer 1995 Aug 9;62(4):398-402

Translocation t(9;22)(q22;q12) is a primary cytogenetic abnormality in extraskeletal myxoid chondrosarcoma.

Stenman G, Andersson H, Mandahl N, Meis-Kindblom JM, Kindblom LG

Department of Pathology, Goteborg University, Sahlgrenska Hospital, Sweden.

The cytogenetic and in vitro growth characteristics of 3 cases of extraskeletal myxoid chondrosarcoma (EMC) are described. In cell culture, the tumor cells retained the immunocytochemical and ultrastructural characteristics of EMC. Cytogenetically, 2 of the cases showed an apparently identical t(9;22)(q22;q12). In one case, the t(9;22) was found together with a dup(I)(q12q44), and in the other case it was found together with several other aberrations. The third case had an inv(10)(p11.2q22) as the sole karyotypic abnormality. Of 4 cases of EMC previously analyzed, 2 showed a t(9;22)(q22;q11-12) and one case of a t(9;22;15)(q31;q12.2;q25). Thus, 5 out of 7 cases of EMC showed recombination between 9q22-31 and 22q11-12, indicating that this represents a tumor specific abnormality. The breakpoints on 22q were in all 5 cases cytogenetically indistinguishable from those seen in Ewing’s sarcoma with t(11;22), clear-cell sarcoma with t(12;22), and desmoplastic small round cell tumors with t(11;22). Molecular cloning of these translocation breakpoints revealed involvement of the EWS gene (located at 22q12) in all 3 tumor types. These observations raise the intriguing question of whether the EWS gene might also be involved in the t(9;22) in EMC.

82: Bull Cancer (Paris) 1995 Aug;82(8):665-73

[Desmoplastic small round cell tumors in adults: a new entity].

Farhat F, Culine S, Lhomme C, Duvillard P, Terrier-Lacombe MJ, Michel G, Soulie P, Theodore C, Lotz JP, Droz JP

Departement de medecine, institut Gustave-Roussy, Villejuif, France.

Desmoplastic small round cell tumor is a recently recognized clinicopathologic entity with distinctive morphologic and immunohistochemical features. Moreover, specific cytogenetic and molecular characteristics have been described. We report here five new adult cases. The median age was 22 years. The clinical presentation was intra-abdominal in four patients and para-testicular in one patient. In patients with intra-abdominal disease, the initial surgery consisted of suboptimal debulking in three patients and only biopsies in the fourth. The patient with para-testicular tumor underwent an orchiectomy. Chemotherapy including cisplatin, etoposide, cyclophosphamide and doxorubicin or epirubicin (PAVEP/PEVEP regimen) was delivered after initial surgery in patients with intra-abdominal presentation or at relapse in the patient with para-testicular tumor. Only one persistent complete response was obtained and no salvage treatment was active in the other patients who died of progressive disease. A review of the literature concerning the clinicopathologic, cytogenetic and molecular features of this new entity is exposed.

83: Am J Surg Pathol 1995 Jun;19(6):659-65

Desmoplastic small round cell tumor of the pleura.

Parkash V, Gerald WL, Parma A, Miettinen M, Rosai J

Department of Pathology, Memorial Sloan Kettering Cancer Center, New York, New York 10021, USA.

Three cases of desmoplastic small round cell tumor (DSRCT) with multiphenotypic differentiation, primary in the pleura, are presented. This is a previously unrecognized site for this tumor type. Two patients were male and one female aged 29, 24, and 17 years. All presented with chest pain and were found to have pleural-based tumors associated with pleural effusion. Abdominal involvement was not present in any of the cases. Histologically, the tumor showed the characteristic features of intra-abdominal DSRCT, including angulated nests of small cells embedded in a vascular fibroblastic stroma, focal rhabdoid phenotype, and areas of central necrosis. The neoplastic cells showed evidence of epithelial, mesenchymal, and neural differentiation with characteristic dot-like positivity for vimentin and desmin topographically corresponding to perinuclear aggregates of intermediate filaments identified on electron microscopy in one case. Two patients died of disease 2 years and 15 months after presentation, respectively, and one patient is alive with disease 18 months after presentation. The histogenesis of DSRCT is unknown. Most previously reported cases involved the peritoneum or tunica vaginalis, suggesting a histogenetic relationship to the mesothelium. The occurrence of these tumors in the pleura lends further support to this theory.

84: Acta Cytol 1995 May-Jun;39(3):514-20

Cytologic features of intraabdominal desmoplastic small round cell tumor. A case report.

el-Kattan I, Redline RW, el-Naggar AK, Grimes MC, Abdul-Karim FW

Institute of Pathology, Case Western Reserve University, Cleveland, Ohio 44106, USA.

Intraabdominal desmoplastic small round cell tumor (IAD-SRCT) is a highly aggressive, malignant neoplasm that affects predominantly young adult males. This report describes the fine needle aspiration and ascitic fluid cytology findings in a 15-year-old male with IAD-SRCT. The tumor cells consisted of small, round to oval cells with a scant amount of basophilic cytoplasm. No cytologic evidence of cellular differentiation was identified. The similarities of cytologic features with other small round cell tumors in the pediatric age group may lead to differential diagnostic difficulties that require the application of ancillary diagnostic methods, such as immunohistochemistry, electron microscopy and cytogenetic techniques. In this case, immunohistochemical stains were positive for cytokeratin, desmin and neuron-specific enolase. Flow cytometry revealed a tetraploid DNA stemline and proliferation index of 21% (S + G2M). Ultrastructural examination revealed undifferentiated small cells with large, perinuclear whorls of intermediate filaments. Cytogenetic studies showed a grossly abnormal karyotype with a t(11;17)(p13;q11.2) translocation and a near-tetraploid modal chromosome number. This karyotype differed from those in previous cases in that it lacked a 22q12-13 fusion partner but provided further evidence for involvement of the 11p13 region in the pathogenesis of this unusual tumor.

85: Acta Cytol 1995 Mar-Apr;39(2):377-8

Desmoplastic small round cell tumor presenting in pleural fluid and accompanied by desmin-positive mesothelial cells.

Choi JK, van Hoeven K, Brooks JJ, Gupta PK

86: JAMA 1995 Feb 15;273(7):553-7

Molecular assays for chromosomal translocations in the diagnosis of pediatric soft tissue sarcomas.

Barr FG, Chatten J, D’Cruz CM, Wilson AE, Nauta LE, Nycum LM, Biegel JA, Womer RB

Department of Pathology and Laboratory Medicine, University of Pennsylvania School of Medicine, Philadelphia 19104-6082.

OBJECTIVE—To compare molecular assays for characteristic chromosomal translocations with standard histopathologic and cytogenetic analysis in the differential diagnosis of pediatric soft tissue sarcomas. DESIGN—Blinded comparison with histopathologic diagnosis. SETTING—Tertiary care children’s hospital. PATIENTS—A total of 79 soft tissue sarcoma patients with frozen tumor tissue and histopathologic slides available for review. METHODS—The RNA from the tumors was assayed by the reverse transcriptase-polymerase chain reaction. These assays detect PAX3-FKHR and PAX7-FKHR chimeric transcripts in alveolar rhabdomyosarcoma, EWS-FLI1 and EWS-ERG chimeric transcripts in Ewing’s sarcoma, and EWS-WT1 chimeric transcripts in desmoplastic small round cell tumor. MAIN OUTCOME MEASURES—The polymerase chain reaction findings were compared with cytogenetic and histopathologic results. RESULTS—These assays detected chimeric transcripts in all cases in which translocations were found by standard cytogenetics as well as additional cases without cytogenetically detectable translocations. PAX3-FKHR or PAX7-FKHR fusions were present in 18 of 21 alveolar rhabdomyosarcomas, two of 30 embryonal rhabdomyosarcomas, and one of seven undifferentiated sarcomas. EWS-FLI1 or EWS-ERG fusions were detected in six of eight Ewing’s sarcomas and one of seven undifferentiated sarcomas. The EWS-WT1 fusion was found in three of three desmoplastic small round cell tumors. CONCLUSIONS—Molecular assays for specific gene fusions provide a genetic approach to the differential diagnosis of soft tissue sarcomas. The genetic categories correspond closely to the standard histopathologic categories. The polymerase chain reaction assays for chimeric transcripts are useful tools for the rapid and objective assessment of pediatric soft tissue sarcomas.

87: Proc Natl Acad Sci U S A 1995 Feb 14;92(4):1028-32

Characterization of the genomic breakpoint and chimeric transcripts in the EWS-WT1 gene fusion of desmoplastic small round cell tumor.

Gerald WL, Rosai J, Ladanyi M

Department of Pathology, Memorial Sloan-Kettering Cancer Center, New York, NY 10021.

Desmoplastic small round cell tumor is a recently recognized distinctive tumor shown to be associated with a recurrent translocation, t(11;22)(p13;q12), and rearrangement of the genes for Ewing sarcoma (EWS) and Wilms tumor (WT1). A genomic DNA fragment containing the EWS-WT1 gene fusion has been isolated from a desmoplastic small round cell tumor, and the breakpoint has been characterized. The breakpoints involve the intron between EWS exons 7 and 8 and the intron between WT1 exons 7 and 8. Chimeric transcripts corresponding to the fusion gene were detected in four of six cases studied. Analysis of these transcripts show an in-frame fusion of RNA encoding the amino-terminal domain of EWS to both alternatively spliced forms of the last three zinc fingers of the DNA-binding domain of WT1. Desmoplastic small round cell tumor represents the third tumor type associated with translocation of EWS and the first tumor associated with consistent translocation of WT1. The chimeric products are predicted to modulate transcription at WT1 target sites and contribute to development of this unique tumor.

88: J Clin Oncol 1995 Jan;13(1):274-82

Molecular and cytogenetic studies in the diagnosis of patients with poorly differentiated carcinomas of unknown primary site.

Motzer RJ, Rodriguez E, Reuter VE, Bosl GJ, Mazumdar M, Chaganti RS

Department of Medicine, Memorial Hospital, New York, NY 10021.

PURPOSE: A minority of patients with poorly differentiated carcinoma achieve a complete response to cisplatin therapy. Recently, specific chromosomal abnormalities have been described for several solid tumor malignancies. Molecular and cytogenetic techniques were used to study tumors of patients with midline carcinoma of unknown primary site. MATERIALS AND METHODS: Forty patients with poorly differentiated carcinoma of unknown primary site had fresh tumor samples studied by cytogenetic analysis, Southern blot analysis for 12p copy number, and fluorescence in situ hybridization (FISH) for the identification of i(12p) and chromosome 12 aneuploidy. The response to cisplatin therapy was correlated to the diagnosis provided by the genetic studies. RESULTS: In 17 (42%) patients, a diagnosis was suggested by the genetic studies. This included a germ cell tumor in 12 (30%) patients by the finding of i(12p), increased 12p copy number, or a deletion of the long arm of chromosome 12. In five patients, a specific diagnosis other than germ cell tumor was suggested by tumor karyotype. These were neuroepithelioma, lymphoma, desmoplastic small-cell tumor, melanoma, and clear-cell sarcoma. The 75% response proportion to cisplatin therapy in patients with tumors showing chromosome structural abnormalities of germ cell tumor was greater than the 18% response proportion in patients for whom no diagnosis was provided (P = .002). CONCLUSION: Molecular and cytogenetic studies are useful in establishing specific diagnoses in patients with poorly differentiated carcinomas of unknown primary site. This group of tumors is heterogeneous and is composed of germ cell tumors, melanoma, lymphoma, neuroepithelioma, and desmoplastic small-round-cell tumor in addition to some that are not yet classifiable. Response to cisplatin therapy correlates with the finding of i(12p) in tumor by either molecular or cytogenetic studies.

89: Virchows Arch 1995;425(6):611-6

Peripheral primitive neuroectodermal tumour and extra-osseous Ewing’s sarcoma; a histological, immunohistochemical and DNA flow cytometric study.

Brinkhuis M, Wijnaendts LC, van der Linden JC, van Unnik AJ, Voute PA, Baak JP, Meijer CJ

Department of Pathology, Free University Hospital, Amsterdam, The Netherlands.

Although peripheral primitive neuroectodermal tumour (pPNET) and extra-osseous Ewing’s sarcoma (EES) are thought to be closely related neoplasms, their clinical behaviour differs considerably. To determine the clinical relevance of the Schmidt classification scheme for differentiating pPNET and EES, 20 tumour specimens of poorly differentiated round cell tumours were evaluated. In addition, the diagnostic value of several neural markers and the prognostic value of quantitative morphological variables (DNA ploidy, S-phase fraction, and the mitotic activity) were assessed. Homer-Wright rosettes were present in 9 tumours. Neuron specific enolase (NSE) was expressed in 11 tumours, 8 of which expressed a second neural marker (CD57, S100, or neurofilament). According to the Schmidt classification, 11 pPNET and 5 EES were distinguished. HBA-71 was exclusively expressed in pPNET and EES. The remaining tumours were classified as sarcoma not otherwise specified (n = 2), rhabdomyosarcoma (n = 1), and desmoplastic tumour with divergent differentiation (n = 1). EES611 patients fared significantly better than the pPNET patients (100% versus 42% 5-year survival). Neither DNA ploidy nor S-phase fraction assessed in 12 evaluative histograms (9 pPNET and 3 EES), nor mitotic activity yielded information of additional prognostic value. On the basis of this study and the Schmidt classification scheme, it can be concluded that if the diagnosis of EES and pPNET is based on light microscopy (Homer-Wright rosettes) and/or immunohistochemistry (at least two neural markers, i.e. NSE, S-100, CD57, and neurofilament), the classification provides important clinical information. Furthermore, positivity for HBA-71 is helpful in differentiating pPNET and EES from all other small round cell tumours.

90: Zentralbl Gynakol 1995;117(7):375-7

[Desmoplastic small cell tumor with multi-phenotype differentiation].

Quiel V

Frauenklinik, Sudharz-Krankenhauses Nordhausen GmbH.

The desmoplastic small cell tumor with divergent differentiation is a malignant tumor with a complex phenotype. Its correct classification remains difficult. The histologic pattern shows tumor cell nests surrounded by a cellular desmoplastic stroma. The immunohistochemical response to epithelial and muscle markers is positive. Neural differentiation and association with cytogenetic abnormality are observed. This tumor probably belongs to the family of primitive small round cell tumors that predominantly occur during childhood.

91: Oncogene 1994 Oct;9(10):3087-97

The EWS gene, involved in Ewing family of tumors, malignant melanoma of soft parts and desmoplastic small round cell tumors, codes for an RNA binding protein with novel regulatory domains.

Ohno T, Ouchida M, Lee L, Gatalica Z, Rao VN, Reddy ES

Department of Microbiology and Immunology, Jefferson Cancer Institute, Philadelphia, PA 19107-5541.

The EWS gene, which maps to band q12 of human chromosome 22, is involved in a wide variety of human solid tumors including Ewing sarcoma, related primitive neuroectodermal tumors, malignant melanoma of soft parts and desmoplastic small round cell tumors. In these tumors, the EWS is fused to genes encoding transcriptional activators/repressors, like Fli-1 or erg or ATF 1 or wt1. To better understand the function of the EWS protein, we cloned the EWS cDNA. Sequence analysis of this cDNA revealed differential splicing involving two exons encoding 72 amino acids. Both alternatively spliced transcripts, EWS and EWS-b, are expressed in a variety of cells. Because EWS proteins contain putative conserved RNA binding motifs, we studied the RNA binding properties of the EWS protein. The EWS-b protein binds to RNA in vitro and, specifically, to poly G and poly U. The RNA binding activity was localized to the carboxy terminal 86 amino acids, which constitute RGG box. Thus the amino terminal domain of EWS (NTD-EWS), which is involved in chromosome translocation may regulate the specificity of RNA binding activity of EWS. An EWS-erg chimeric protein, which is found in Ewing’s sarcoma cells, functions as a transcriptional activator. Mutational analysis of EWS-erg chimeric protein revealed that NTD-EWS functions as a regulatory domain for the transcriptional activation properties of EWS-erg chimeric protein.

92: Cancer Res 1994 Jun 1;54(11):2837-40

Fusion of the EWS and WT1 genes in the desmoplastic small round cell tumor.

Ladanyi M, Gerald W

Department of Pathology, Memorial Sloan-Kettering Cancer Center, New York, New York 10021.

The desmoplastic small round cell tumor (DSRCT) is a recently recognized type of primitive sarcoma defined by a predilection for young males, aggressive clinical behavior, widespread abdominal serosal involvement, and a primitive histological appearance with prominent desmoplasia and striking divergent, multilineage differentiation. Previous cytogenetic case reports have identified a recurrent translocation, t(11;22) (p13;q12). We have characterized this translocation at the molecular level in a panel of five DSRCTs using a candidate gene approach. Southern blot analysis revealed recurrent rearrangement of both EWS, located at 22q12, and rearranged in other tumor-specific translocations in Ewing’s sarcoma and clear cell sarcoma, and of WT1, the gene at 11p13 involved in a subset of Wilms’ tumor. Consistent comigration of the rearranged EWS and WT1 bands in multiple enzyme digests indicated fusion of the genomic sequences, presumably due to the translocation t(11;22) (p13;q12). Northern blotting showed aberrant EWS and WT1 transcripts of the same size, suggesting the presence of a chimeric messenger RNA. This was confirmed by reverse transcriptase polymerase chain reaction using an EWS exon 7 primer and WT1 exon 8 or 9 primers, which revealed single polymerase chain reaction products consistent with a junction of EWS exon 7 to WT1 exon 8. DSRCT thus represents the third primitive sarcoma in which the EWS gene is involved and the first instance of recurrent rearrangement of a tumor suppressor gene, WT1, in a specific tumor type. The different translocation partners of the EWS gene, all of which are putative or definite transcription factor genes, may be responsible for the biological differences between DSRCT, Ewing’s sarcoma, and clear cell sarcoma.

93: Histopathology 1994 Jun;24(6):577-9

Intra-abdominal desmoplastic small round-cell tumour with expression of muscle specific actin.

Lamovec J

Department of Pathology, Institute of Oncology, Ljubljana, Slovenia.

94: Ultrastruct Pathol 1994 May-Jun;18(3):389-98

Intra-abdominal desmoplastic small round cell tumor of the peritoneum in a young man.

Devaney K

Department of Pathology, Brown University, Rhode Island Hospital, Providence 02903.

The desmoplastic small round cell tumor (DSRCT) has a predilection for involvement of the peritoneal surfaces of young adult men. The tumor has an extremely poor prognosis: despite aggressive therapy the patients usually die of disease within the first 2 years following diagnosis. The present report details the pathologic features of a pelvic tumor, which proved to be a DSRCT, arising in a previously healthy 24-year-old man. The light microscopic features were typical of a DSRCT—the tumor cells were small and round, had inconspicuous cytoplasm, and were grouped into distinctive islands and cords that were dispersed in a fibrous stroma. The immunohistochemical features were likewise characteristic of DSRCT in that the tumor cells were positive for cytokeratin, vimentin, epithelial membrane antigen, and desmin. Ultrastructurally, the tumor cells were distinguished by an abundance of intercellular junctions, cytoplasmic lipid droplets, cytoplasmic intermediate filaments, and an absence of surface microvilli. Recognition of this tumor type is important in view of both its clinical features (extremely poor prognosis despite therapy) and its potential to shed some light on the nature of the family of lesions that has traditionally been classified by light microscopists as small round cell tumors.

95: Cancer 1994 Mar 15;73(6):1753-6

Desmoplastic small round cell tumors of the abdomen.

Frappaz D, Bouffet E, Dolbeau D, Bouvier R, Carrie C, Louis D, Pondarre C, Tabone E, Philip T, Brunat-Mentigny M

Pediatric and Pathology Department, Centre Leon Berard, France.

BACKGROUND. Desmoplastic small round cell tumors (DSRCT) have been only recently identified.
METHODS. The authors report DSRCT in two pediatric patients (an 8-year-old boy and 12-year-old boy). In both patients, the initial diagnosis was rhabdomyosarcoma. The resistance to standard chemotherapy and radiation therapy prompted the authors to review the initial biopsy specimens and perform complementary immunophenotypic characterization.
RESULTS. These analyses revealed that the tumor cells were strongly positive for keratin epithelial marker antigen, desmin, vimentin, neurospecific enolase, and S100 protein, corresponding to pleomorphic differentiation, characteristic of DSRCT.
CONCLUSIONS. The authors suggest that extensive immunohistologic characterization be performed in all cases of small round cell tumors of the abdomen so that the diagnosis of DSRCT is not overlooked. These rare tumors are refractory to chemotherapy, and initial aggressive surgery is warranted.

96: Acta Cytol 1994 Mar-Apr;38(2):209-17

Cytology of fluids from pleural, peritoneal and pericardial cavities in children. A comprehensive survey.

Hallman JR, Geisinger KR

Department of Pathology, Bowman Gray School of Medicine, Winston-Salem, North Carolina.

We reviewed all cytologic specimens of pleural, peritoneal and pericardial fluids examined in our laboratory from patients aged 0-17 years during a 12-year period. A total of 103 specimens were studied: 45 pleural, 54 peritoneal and 4 pericardial. Twenty-two of the 103 specimens were peritoneal washes. Eleven of the 81 (14%) serous effusion specimens contained tumor cells: 8 lymphomas, 1 leukemia, 1 abdominal desmoplastic small round cell tumor and 1 Wilms’ tumor. Two false-positive diagnoses were made in patients presenting with ascites with an unknown case. Both cases were complicated by the presence of atypical mononuclear cells and illustrate a potential pitfall in the evaluation of pediatric serous effusions. We conclude: (1) Almost all pediatric effusions are benign. (2) Malignant pediatric effusions are usually caused by neoplasms of the small cell type, mostly lymphoreticular. (3) The major diagnostic difficulty in interpreting pediatric effusion cytology is in distinguishing neoplasms of the small cell type from mononuclear inflammatory cells. (4) The usefulness of peritoneal washings in pediatric patients is similar to that in adults.

97: J Urol 1994 Jan;151(1):172-3

Urological aspects of intra-abdominal desmoplastic small round cell tumor of childhood: a preliminary report.

Carroll JC, Klauber GT, Kretschmar CS, Ucci A, Cendron M

Department of Pediatric Urology, Tufts University School of Medicine, Boston Floating Hospital, Massachusetts.

To our knowledge intra-abdominal desmoplastic round cell tumor has not previously been described in the pediatric urological literature. This lesion has only recently been recognized as a clinicopathological entity with predilection for adolescent boys. We report on 2 patients who presented with urological symptoms and a large abdominal or pelvic tumor that was biopsied at exploratory laparotomy. Complete surgical excision was impossible in both patients, who subsequently underwent multiagent chemotherapy. Histological and immunohistochemical staining are distinctive in this condition. The tumor is associated with a poor prognosis, despite multidisciplinary, multimodal therapy.

98: Diagn Cytopathol 1994;10(3):245-55

FNA biopsy of small round cell tumors of childhood: cytomorphologic features and the role of ancillary studies.

Silverman JF, Joshi VV

Department of Pathology and Laboratory Medicine, East Carolina University School of Medicine, Greenville, NC 27858-4354.

Pediatric tumors which are conventionally considered to be small round cell tumors (SRCTs) include the prototypical neuroblastoma as well as rhabdomyosarcoma (RMS), Ewing’s sarcoma (ES), malignant lymphoma, and primitive neuroectodermal tumor (PNET). Other malignancies may be considered in the differential diagnosis such as small-cell osteogenic sarcoma, undifferentiated (anaplastic) hepatoblastoma, granulocytic sarcoma, blastemal type Wilms’ tumor, and desmoplastic small-cell tumor of the peritoneum. The cytomorphologic features of conventional SRCTs is presented as well as the utility of ancillary studies performed on the aspirated material in making a specific and correct diagnosis. The role of the immediate cytologic assessment of the aspirate is stress, since this is a critical step in formulating an initial diagnostic impression that should prompt the need for additional material for pertinent ancillary studies. Although challenging, FNA cytology of SRCTs of childhood can be diagnostic in the majority of cases, allowing specific therapy to be given to patients with unresectable SRCTs without a tissue biopsy as well as documenting recurrent and/or metastatic disease.

99: Eur J Gynaecol Oncol 1994;15(4):267-71

Intra-abdominal desmoplastic small round-cell tumor in a postmenopausal female. Report of a case and review of the literature.

Mead M, Jones MA, Decain M, Tarraza HM

Department of Obstetrics and Gynecology, Maine Medical Center, Portland.

Intra-abdominal desmoplastic small round cell tumor is a rare malignancy which tends to occur in adolescent males. Fewer than 30 cases of this malignancy have been described, and long term survival is poor. We present a case of intra-abdominal desmoplastic small round cell tumor occurring in a post-menopausal woman that mimicked ovarian carcinoma. The clinicopathologic features and literature are reviewed.

100: Diagn Cytopathol 1994;11(2):159-64

Small round cell tumor with divergent differentiation: cytologic, histologic, and ultrastructural findings.

Akhtar M, Ali MA, Sabbah R, Bakry M, al-Dayel F

Department of Pathology and Laboratory Medicine, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia.

A case study of desmoplastic small round cell tumor with divergent differentiation in a 13-yr-old boy is presented. Clinical, cytologic, histologic, immunohistochemical, and ultrastructural findings are reported. There was a close correlation between the various histologic and cytologic patterns. Immunohistochemical studies revealed strong positivity of many of the tumor cells for cytokeratin, vimentin, and desmin. Ultrastructurally, some of the tumor cells contained aggregates of cytoplasmic intermediate filaments. Fine-needle aspiration biopsy may suggest the diagnosis of desmoplastic small round cell tumor. Confirmation of the diagnosis may be provided by immunohistochemistry and electromicroscopy.

101: Cold Spring Harb Symp Quant Biol 1994;59:137-46

Novel oncogenic mutations in the WT1 Wilms’ tumor suppressor gene: a t(11;22) fuses the Ewing’s sarcoma gene, EWS1, to WT1 in desmoplastic small round cell tumor.

Rauscher FJ 3^rd, Benjamin LE, Fredericks WJ, Morris JF

Wistar Institute, Philadelphia, Pennsylvania 19104, USA.

These studies suggest that the WT1 tumor suppressor gene, originally identified as a recessive oncogene in Wilms’ tumors, is capable of sustaining a gain-of-function mutation which results in its contribution to a completely different disease entity: desmoplastic small round cell tumor. Two independent biochemical functions of WT1, DNA-binding activity and mode of transcriptional regulation, are altered as a consequence of the chromosomal translocation and fusion with EWS. The fusion of EWS and WT1 genes in DSRCT thus provides a unique paradigm for a means by which different alterations of transcription factor function can lead to diverse oncogenic processes.

102: Histopathology 1993 Dec;23(6):557-61

Immunocytochemical study of 12E7 in small round-cell tumours of childhood: an assessment of its sensitivity and specificity.

Ramani P, Rampling D, Link M

Department of Histopathology, Hospital for Sick Children, London, UK.

12E7 is a monoclonal antibody to the MIC2 gene product and can be applied to formalin-fixed, paraffin-embedded tissue. The diagnostic utility of 12E7 as a marker of Ewing’s sarcoma and peripheral neuroectodermal tumour was assessed. Immunocytochemical studies were performed on 120 small round-cell tumours from children and adolescents. Immunoreactivity for 12E7 was seen in 13 of 15 Ewing’s sarcomas. 14 of 15 peripheral neuroectodermal tumours, four of 14 embryonal rhabdomyosarcoma, seven of 11 T-lymphoblastic lymphomas and one T-cell acute lymphoblastic leukaemia. Immunoreactivity was located on the cell-membrane of Ewing’s sarcomas, peripheral neuroectodermal tumours and lymphoid tumours while rhabdomyosarcomas showed weak, cytoplasmic staining in differentiated rhabdomyoblasts. Studies on alveolar rhabdomyosarcomas (n = 10), acute myeloid leukaemias (3), B-lymphoblastic lymphomas (8), blastema-rich nephroblastomas (9), neuroblastomas (20) and retinoblastomas (10) as well as single examples of B-cell acute lymphoblastic leukaemia, Ki-1 anaplastic lymphoma of indeterminate phenotype and intra-abdominal desmoplastic tumour with divergent differentiation were negative. 12E7 is a sensitive marker for the Ewing’s sarcoma/peripheral neuroectodermal group of tumours and is useful in distinguishing them from neuroblastoma and blastema-rich nephroblastoma. However, immunopositivity for 12E7 should be interpreted in conjunction with the results of neural and lymphoid markers.

103: Cancer Genet Cytogenet 1993 Aug;69(1):17-21

A recurring translocation, t(11;22)(p13;q11.2), characterizes intra-abdominal desmoplastic small round-cell tumors.

Rodriguez E, Sreekantaiah C, Gerald W, Reuter VE, Motzer RJ, Chaganti RS

Cell Biology and Genetics Program, Memorial Sloan-Kettering Cancer Center, New York, NY 10021.

We report the cytogenetic analysis of two cases of intra-abdominal desmoplastic small round-cell tumor, one of which had a t(11;22)(p13;q11.2) translocation. The same translocation has previously been reported in two other cases analyzed cytogenetically, indicating that it could be a consistent abnormality characteristic of this rare tumor entity.

104: Diagn Cytopathol 1993 Aug;9(4):465-70

Fine-needle aspiration of intra-abdominal desmoplastic small cell tumor.

Caraway NP, Fanning CV, Amato RJ, Ordonez NG, Katz RL

Department of Pathology, University of Texas M. D. Anderson Cancer, Houston 77030.

The cytologic features of four cases of histologically confirmed intra-abdominal desmoplastic small cell tumor (DSCT) that occurred in males between 18-27 yr of age are presented. Smears showed small cells with scant cytoplasm which were primarily arranged in loosely cohesive clusters. Nuclei were oval to round with evenly distributed, finely granular chromatin and inconspicuous nucleoli. As is typical of DSCT, the cells strongly expressed keratin and desmin in all cases. In the one case studied by electron microscopy, it was demonstrated that the cells were joined by small junctions and contained paranuclear aggregates of intermediate filaments. The absence of the characteristic desmoplastic stroma in DSCT aspirates and the nonspecific cytologic features of this small round-cell tumor (SRCT) made cytologic interpretation difficult. Cytopathologists should be aware of this entity so that DSCT is included in the differential diagnosis of SRCTs that occur in intra-abdominal sites. A panel of markers that includes keratin and desmin should be used to assist in the identification of DSCT.

105: J Pediatr Surg 1993 Aug;28(8):1023-5

The desmoplastic round cell tumor: a new solid tumor of childhood.

Crombleholme TM, Harris BH, Jacir NN, Latchaw LA, Kretschmar CS, Rosenfield CG, Wolfe LC, Cendron M, Trask C, Wolfe HJ

Department of Pediatric Surgery, Tufts University School of Medicine, Boston, MA.

Three patients with a new, pathologically distinct solid tumor of childhood have been treated recently. The disease is characterized by male predominance, adolescent onset, an extensive abdominal primary tumor, and aggressive metastases to regional lymph nodes, liver, and lung. Two patients presented with vague abdominal pain and the third with testicular pain. All three noted fatigue and malaise of less than two months’ duration with minimal associated weight loss. Computed tomography (CT) scans of the abdomen and chest were obtained for initial preoperative staging, and then all three underwent surgical exploration. Widespread disease was found in each case. In no instance was complete tumor extirpation possible because of extensive peritoneal spread and lymphatic and hepatic metastases. Histologically, all three tumors consisted of round blue cells with a dense desmoplastic reaction and focal rhabdoid features. Immunohistochemical markers for epithelial, neural, and muscle elements were positive. Aggressive multidrug chemotherapeutic regimens were used in each case, and all three patients are alive and well but with known residual disease. We conclude that in cases of the desmoplastic round cell tumor of childhood, CT scans underestimate the extent of disease, and exploratory laparotomy is necessary for diagnosis and appropriate staging. Surgery is usually palliative because of extensive spread. Awareness of this newly recognized aggressive solid tumor of childhood is essential to define its natural history and guide the development of effective multidisciplinary therapeutic regimens.

106: Histopathology 1993 Jul;23(1):1-9

Divergent differentiation in small round-cell tumours of the soft tissues with neural features—an analysis of 10 cases.

Pearson JM, Harris M, Eyden BP, Banerjee SS

Department of Histopathology, Christie Hospital, Manchester, UK.

A series of 10 small round-cell tumours, having in common evidence of neural differentiation, were investigated by immunohistochemistry and electronmicroscopy. In seven, evidence of divergent muscle and/or epithelial differentiation was found. This phenomenon thus appears more common than previously appreciated and suggests that there may be a continuous and overlapping phenotypic spectrum from Ewing’s tumour of soft tissue to intra-abdominal desmoplastic small cell tumour.

Comment in: Histopathology 1993 Jul;23(1):93-7

107: Zentralbl Pathol 1993 Jun;139(2):141-51

Desmoplastic small cell tumor with multi-phenotypic differentiation.

Gerald WL, Rosai J

Department of Pathology, Memorial Sloan-Kettering Cancer Center New York, New York.

Desmoplastic small cell tumor (DSCT) is a distinctive, poorly understood malignant tumor with a complex phenotype. The main features of the 46 cases presented here include a mean age of 20.8 years (range 7-48), male predominance (37 M:9 F), primary intraabdominal location (except for 2 cases), characteristic histologic pattern consisting of tumor cell nests surrounded by a cellular desmoplastic stroma, immunohistochemical reactivity for markers of epithelial, muscle and neural differentiation, and association with a unique cytogenetic abnormality. These findings suggest that this tumor is a distinct neoplastic process and that it probably belongs to the family of primitive small round cell developmental tumors. It is proposed that DSCT arises during development from a progenitor cell with potential for multiphenotypic differentiation.

108: Genes Chromosomes Cancer 1993 Jun;7(2):119-21

Translocation (11;22)(p13;q12): primary change in intra-abdominal desmoplastic small round cell tumor.

Biegel JA, Conard K, Brooks JJ

Division of Human Genetics, Children’s Hospital of Philadelphia, PA 19104.

We present the cytogenetic findings in a case of a newly described tumor of childhood, intra-abdominal desmoplastic small round cell tumor (IADSRCT). The karyotype demonstrated a single chromosomal translocation, (11;22)(p13;q12).

109: Ultrastruct Pathol 1993 May-Aug;17(3-4):295-306

Peritoneal desmoplastic small round cell tumors with divergent differentiation: a review.

Wills EJ

Department of Anatomical Pathology, Royal Prince Alfred Hospital, Camperdown, NSW, Australia.

Peritoneal desmoplastic small round cell tumors with divergent differentiation are recently described highly aggressive neoplasms with characteristic clinical, morphologic, and immunohistochemical features. This review covers 38 cases that have been reported in the literature. The average age of patients is 18.4 years, and males are affected twice as frequently as females. Tumors generally present as multiple peritoneal nodules without obvious organ involvement. Histology shows islands of small cells set in dense desmoplastic stroma. Immunohistochemical stains are usually positive for cytokeratins, epithelial membrane antigen, desmin, and vimentin. Many cases also stain for neuron-specific enolase but rarely for other neuroepithelial markers. Ultrastructural appearances range from undifferentiated small cells to larger epithelial elements. Paranuclear aggregates of intermediate filaments are characteristic. Dense-core granules and other neuroendocrine features have been described in a minority of cases. Some tumors respond to chemotherapy, but most patients die within months to a few years. The histogenesis of these tumors is uncertain.

110: Pathology 1993 Apr;25(2):197-202

Published erratum appears in Pathology 1993 Jul;25(3):326 Intra-abdominal desmoplastic small round cell tumor.

Yeoh G, Russell P, Wills EJ, Fleming S

Department of Anatomical Pathology, Royal Prince Alfred Hospital, Sydney.

A rarely encountered but distinctive type of aggressive malignant tumor of childhood and adolescence has been recently described as occurring predominantly or exclusively intrabdominally. It is characterized by a generally diffuse pattern of growth of small cells with hyperchromatic nuclei, scanty cytoplasm, patchy epithelial differentiation, immunohistochemical co-expression of keratin and desmin intermediate filaments and a focal but pronounced desmoplastic stromal component. It is regarded as yet another variant in the group of small round cell tumors (SRCT) of infancy and childhood. This case report of a mass in the greater omentum of a 15 yr-old girl adds to the 33 cases already described in the English literature.

111: Aust N Z J Surg 1993 Feb;63(2):157-9

Intra-abdominal desmoplastic small round cell tumour.

Miliauskas JR, Abbott RL, Sarre R

Gribbles Pathology, Adelaide, Australia.

Intra-abdominal desmoplastic small round cell tumour is a rare tumour which has only recently been described. It demonstrates epithelial, mesenchymal and neural features and has an aggressive clinical course. We report a case of a 15 year old male with this tumour who, after debulking surgery and chemotherapy, relapsed with disease 1 month later. After further debulking surgery, extensive chemotherapy and bone marrow transplantation he relapsed with disease 5 months later and died. Total survival was 20 months.

112: Am J Surg Pathol 1993 Jan;17(1):1-13

Primitive neuroectodermal tumor and Ewing’s sarcoma.

Dehner LP

Department of Pathology, Barnes Hospital, Washington University Medical Center, St. Louis, Missouri 63110.

Many of the major solid, malignant tumors of childhood have histologic similarities that reflect their dysembryonic and primitive features. One subset of these neoplasms, Ewing’s sarcoma (ES) and primitive neuroectodermal tumor (PNET), presents primarily in the bone and soft tissues. Both tumor types were reported at a time and date well before the advent of electron microscopy and immunohistochemistry. Opposition to ES and PNET as distinctive entities developed and persisted because these tumors were considered incompletely documented examples of metastatic neuroblastoma or malignant lymphoma. General acceptance of ES as a unique tumor type occurred well before the PNET had been fully defined and characterized. Once these neoplasms had joined the other round cell neoplasms, the quest for the histogenesis was pursued, but the results were frustratingly inconclusive, especially for ES. Because of the resemblance of the PNET to classic neuroblastoma, the neural crest was regarded as the most likely progenitor. With the recognition of osseous PNET, extraosseous ES, and a shared cytogenetic abnormality between ES and PNET, more recent speculation has focused on the possibility that these presumably separate neoplasms are closely related histogenetically without directly answering the question of histogenesis. Despite the likely common progenitorship of ES and PNET, the latter neoplasm is seemingly the more aggressive. Although melanotic neuroectodermal tumor of infancy, intra-abdominal desmoplastic small cell tumor, and polyphenotypic small cell tumors have some overlapping microscopic and immunohistochemical features with PNET, their relationship to ES-PNET has otherwise not been resolved.

113: Acta Cytol 1993 Jan-Feb;37(1):77-82

Effusion cytology of desmoplastic small round cell tumor of the pleura. A case report.

Bian Y, Jordan AG, Rupp M, Cohn H, McLaughlin CJ, Miettinen M

Department of Surgery, Thomas Jefferson University Hospital, Philadelphia, Pennsylvania 19107.

Desmoplastic small round cell tumor is a recently described neoplasm with multidirectional differentiation. Although it occurs predominantly in adolescent males as an intraabdominal mass with multiple peritoneal implants, we report a case with primary pleural involvement. The cytologic features correspond to previously reported histologic findings and include tightly cohesive clusters of small round poorly differentiated malignant cells with accompanying desmoplastic stromal cells. Immunohistochemical studies revealed characteristic reactivity to epithelial markers, desmin and one neuroendocrine marker (chromogranin). We believe that together with clinical and immunohistochemical data, desmoplastic small round cell tumor can be diagnosed in effusion or aspiration cytology specimens.

114: Histopathology 1992 Jun;20(6):531-4

Intra-abdominal desmoplastic small round-cell tumour.

Cheung NY, Khoo US, Chan KW

Department of Pathology, University of Hong Kong, Queen Mary Hospital.

115: Acta Cytol 1992 May-Jun;36(3):373-6

Intraabdominal desmoplastic small round cell tumor. Report of a case diagnosed by fine needle aspiration cytology.

Setrakian S, Gupta PK, Heald J, Brooks JJ

Section of Cytopathology and Cytometry, University of Pennsylvania, Philadelphia.

In this report, fine needle aspiration (FNA) findings in a case of intraabdominal desmoplastic small round cell tumor (IADSRCT) are presented. Computed tomographic scan-guided FNA performed on a right upper abdominal mass on a 20-year-old man produced a cellular specimen consisting of monomorphic small round cells with scant cytoplasm and ovoid nuclei. FNA cytology and immunocytochemistry suggested the diagnosis of IADSRCT. Surgical removal of the tumor and detailed histology and ultrastructural studies confirmed the cytologic findings.

116: Hum Pathol 1992 Apr;23(4):454-64

Ovarian involvement by the intra-abdominal desmoplastic small round cell tumor with divergent differentiation: a report of three cases.

Young RH, Eichhorn JH, Dickersin GR, Scully RE

Department of Pathology, Harvard Medical School, Boston, MA.

Three girls, one 14 and two 15 years of age, with the recently described neoplasm that has been designated "intra-abdominal desmoplastic small round cell tumor with divergent differentiation," and ovarian involvement at presentation are described. In two cases the ovarian tumor was initially thought to be the primary neoplasm. In all cases there was extensive extraovarian tumor at the time of presentation. The ovarian involvement was bilateral in two cases and unilateral in the third. Microscopic examination showed prominent nodular growth within the ovaries. The tumors were characterized predominantly by nests of small cells with hyperchromatic nuclei and scant cytoplasm separated by a prominent desmoplastic stroma. A few tubules containing mucinous secretion were present in one case. On immunohistochemical staining many of the tumor cells stained positively for cytokeratin, epithelial membrane antigen, desmin, and vimentin. Staining for neuron-specific enolase was present in two cases but was conspicuous in only one of them. Leu-7 was expressed by the tumor cells in two cases, and S-100 protein by one, giving further support to the possibility of neuroectodermal differentiation within some of these neoplasms. The two cases studied by electron microscopy both showed frequent intercellular junctions, basal lamina, cytoplasmic filaments, and sparse, small dense granules of either neuroendocrine or lysosomal type. Paranuclear aggregates of filaments were found in one case and cellular processes were prominent in the other case. The differential diagnosis in these cases was extensive and included a number of small cell tumors that may involve the ovary, either primarily or secondarily, in young females. The desmoplastic small round cell tumor should be considered in such cases when the appearances on routine examination are consistent with the diagnosis, and appropriate immunohistochemical stains should be performed to confirm the diagnosis.

117: Am J Surg Pathol 1992 Apr;16(4):411-6

A novel reciprocal chromosome translocation t(11;22)(p13;q12) in an intraabdominal desmoplastic small round-cell tumor.

Sawyer JR, Tryka AF, Lewis JM

Department of Pathology, University of Arkansas for Medical Sciences, Little Rock.

We report an intraabdominal desmoplastic small round-cell tumor that contains a novel reciprocal chromosome translocation t(11;22)(p13;q12). The tumor showed a reciprocal chromosome translocation which is different from the (11;22)(q24;q12) translocations seen in Ewing’s and other small-cell tumors but affects the same break-point on chromosome 22(q12). This reciprocal chromosome translocation may prove to be a marker for intraabdominal desmoplastic small round-cell tumors.

118: Am J Surg Pathol 1992 Mar;16(3):306-7

Desmoplastic small round-cell tumor.

Prat J, Matias-Guiu X, Algaba F

Comment on: Am J Surg Pathol 1991 Jun;15(6):499-513

119: Am J Pathol 1991 Aug;139(2):317-25

Immunohistochemical analysis of Ewing’s sarcoma cell surface antigen p30/32MIC2.

Fellinger EJ, Garin-Chesa P, Triche TJ, Huvos AG, Rettig WJ

Department of Immunology, Memorial Sloan-Kettering Cancer Center, New York, New York 10021.

Monoclonal antibody (MAb) HBA71, which was raised against Ewing’s sarcoma cells, recognizes a cell-surface glycoprotein, p30/32MIC2, that is encoded by the MIC2 gene in the pseudoautosomal region of human chromosomes X and Y. This immunohistochemical study evaluates the specificity and sensitivity of MAb HBA71 for tumor diagnosis. Frozen and paraffin-embedded tissues of more than 300 tumors of diverse histologic type, including more than 100 small round cell tumors of childhood and adolescence, were tested with this MAb by the avidin-biotin immunoperoxidase procedure. The authors found HBA71 immunoreactivity in 61 of 63 Ewing’s sarcomas studied and 9 of 11 primitive neuroectodermal tumors and peripheral neuroepitheliomas. HBA71-negative tumors included neuroblastomas (0 of 24), melanomas (0 of 13), an esthesioneuroblastoma, small cell osteosarcomas (0 of 2), a malignant ectomesenchymoma, desmoplastic SRCT (0 of 5), and medulloblastomas (0 of 5). Heterogeneous expression of HBA71 immunostaining was found in some embryonal rhabdomyosarcomas (3 of 14) and astrocytomas (4 of 7), and in a few neuroendocrine tumors (4 of 26), carcinomas (3 of 94), and lymphomas (6 of 30). Because Ewing’s sarcomas are consistently HBA71 positive, the authors searched for antigen-positive normal cells that may represent precursors for these tumors; however, no obvious candidate for the elusive cell of origin for Ewing’s sarcoma was identified in the normal fetal tissues tested. Their findings indicate that HBA71 is a highly restricted cell-surface antigen of Ewing’s sarcomas and primitive neuroectodermal tumors, and immunohistochemistry employing this antibody may be of value in the differential diagnosis of selected small round cell tumors in childhood and adolescence.

120: Am J Surg Pathol 1991 Jun;15(6):499-513

Intra-abdominal desmoplastic small round-cell tumor. Report of 19 cases of a distinctive type of high-grade polyphenotypic malignancy affecting young individuals.

Gerald WL, Miller HK, Battifora H, Miettinen M, Silva EG, Rosai J

Department of Pathology, Yale University Medical School, New Haven, Connecticut.

Nineteen cases of a distinctive type of malignant small-cell tumor are presented. The main features of the entity are as follows: a predilection for adolescent males (mean age: 18.6 years); predominant or exclusive intra-abdominal location, with only inconstant and secondary organ involvement; nesting pattern of growth; focal rhabdoid features; intense desmoplastic reaction; immunohistochemical reactivity for epithelial [keratin, epithelial membrane antigen (EMA)], neural [neuron-specific enolase (NSE)], and muscle (desmin) markers; and highly aggressive behavior. It is proposed that this represents yet another member of the continuously enlarging and evolving family of small round (blue) cell tumors of infancy and childhood that features, more than any other member of this group, the capacity for simultaneous multidirectional phenotypical expression.

Comment in: Am J Surg Pathol 1992 Mar;16(3):306-7