title: Ewing sarcoma/peripheral primitive neuroectodermal tumor: adult abdominal tumors with an Ewing sarcoma gene rearrangement demonstrated by fluorescence in situ hybridization in paraffin sections.
abstract: The differential diagnosis of small round cell tumors is exhaustive and requires ancillary studies. Relatively recently, fluorescence in situ hybridization (FISH) using probes for specific gene rearrangements has gained wide acceptance. This technique is particularly useful in the differential diagnosis of Ewing sarcoma/primitive neuroectodermal tumor (ES/PNET) and desmoplastic small round-cell tumor (DSRCT). In ES/PNET, the EWS gene is juxtaposed to the FLI-1 gene in 85% of cases and to the ERG gene in another 7% of cases; the EWS gene is juxtaposed to the WTI gene in DSRCT. Documentation of the EWS gene rearrangements in EWS/PNET has previously been demonstrated in frozen tissue. We report 2 unusual cases of EWS/PNET diagnosed in abdominal tumors in adults. Although the immunohistochemical results supported a diagnosis of ES/PNET, 1 case morphologically resembled DSRCT. The diagnosis in these 2 cases was confirmed by the FISH demonstration of EWS/FLI-1 gene fusion in paraffin-embedded tissue. Thus, the usefulness of FISH demonstration of an EWS gene rearrangement with these specific probes in such unusual cases is supported and is demonstrated in paraffin-embedded tissue.
authors.affiliation: Division of Hematopathology, Department of Pathology, St. Louis University Health Sciences Center, St. Louis, Missouri, USA.
authors.forename: Laura J
authors.initials: LJ
authors.lastname: Gardner
authors.forename: Alberto G
authors.initials: AG
authors.lastname: Ayala
authors.forename: Hector L
authors.initials: HL
authors.lastname: Monforte
authors.forename: Cherie H
authors.initials: CH
authors.lastname: Dunphy
mesh_terms: D000008:Abdominal Neoplasms / Q000175:diagnosis / Q000235:genetics; D018288:Carcinoma, Small Cell / Q000473:pathology; D003937:Diagnosis, Differential; D005260:Female; D015321:Gene Rearrangement; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D008297:Male; D008875:Middle Aged; D018241:Neuroectodermal Tumors, Primitive, Peripheral / Q000175:diagnosis* / Q000235:genetics; D015514:Oncogene Proteins, Fusion / Q000235:genetics; D016612:Paraffin Embedding; D051789:Proto-Oncogene Protein c-fli-1; D034802:RNA-Binding Protein EWS / Q000235:genetics*; D012512:Sarcoma, Ewing / Q000175:diagnosis* / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics
chemical_list: C106031:EWS-FLI fusion protein; D015514:Oncogene Proteins, Fusion; D051789:Proto-Oncogene Protein c-fli-1; D034802:RNA-Binding Protein EWS; D014157:Transcription Factors