title: Extraskeletal Ewing sarcoma in a 77-year-old woman.
abstract: Extraskeletal Ewing sarcoma (EES) is a rare soft tissue tumor that is morphologically indistinguishable from Ewing sarcoma of bone. It is usually found in young people, but several cases have occurred in patients older than 50 years. The differential diagnoses include other small, blue round cell tumors (SBRCTs) and other members of the Ewing family of tumors such as the primitive neuroectodermal tumor. We present a case of EES in the left inguinal region of a 77-year-old woman. The tumor was distinguished from other SBRCTs by lack of immunoreactivity for epithelial, lymphoid, vascular, neuroendocrine, neural, histiocytic, and muscle markers. Primitive neuroectodermal tumor was excluded because of the lack of neural differentiation by histologic analysis, immunohistochemistry, and electron microscopy. Extraskeletal Ewing sarcoma was confirmed by characteristic features on histologic analysis, histochemistry, immunohistochemistry, and electron microscopy and by the presence of the t(11;22)(q24;q12) fusion transcript detected by reverse transcriptase-polymerase chain reaction. This case serves to remind the reader that EES is not a tumor that occurs exclusively in young patients.
authors.affiliation: Department of Laboratory Medicine and Pathobiology, University Health Network, University of Toronto, Toronto, Ontario, Canada.
authors.forename: C C
authors.initials: CC
authors.lastname: Cheung
authors.forename: R A
authors.initials: RA
authors.lastname: Kandel
authors.forename: R S
authors.initials: RS
authors.lastname: Bell
authors.forename: R E
authors.initials: RE
authors.lastname: Mathews
authors.forename: D M
authors.initials: DM
authors.lastname: Ghazarian
mesh_terms: D000368:Aged; D001706:Biopsy; D001707:Biopsy, Needle; D002880:Chromosomes, Human, Pair 11; D002892:Chromosomes, Human, Pair 22; D005260:Female; D006119:Groin; D006801:Humans; D007150:Immunohistochemistry; D008854:Microscopy, Electron; D015514:Oncogene Proteins, Fusion / Q000235:genetics; D051789:Proto-Oncogene Protein c-fli-1; D034802:RNA-Binding Protein EWS; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012512:Sarcoma, Ewing / Q000175:diagnosis* / Q000235:genetics / Q000473:pathology; D014057:Tomography, X-Ray Computed; D014157:Transcription Factors / Q000235:genetics; D014178:Translocation, Genetic; D014463:Ultrasonography; D014746:Vimentin / Q000032:analysis
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; D014746:Vimentin