title: Beware of immunohistochemistry--report of a cytokeratin-, desmin- and INI-1-negative pelvic desmoplastic small round cell tumor in a 51 year old woman.
abstract: We present a 51 year old female patient with a pelvic desmoplastic small round cell tumor with an unusual immunohistochemical profile, including absence of significant cytokeratin expression, complete negativity for desmin and widespread loss of nuclear INI-1 expression (>90% of tumor cells). The neoplastic cells were positive for epithelial membrane antigen (EMA), vimentin, and WT-1 (antibody against the C-terminus). The tumor showed classic histopathological features with no rhabdoid cells. Fluorescent in situ hybridization revealed EWSR1 gene rearrangement and absent SYT gene rearrangement. Reverse transcriptase polymerase chain reaction showed presence of EWSR1-WT1 transcript.
authors.affiliation: Department of Pathology, National University Health System Singapore.
authors.forename: Gwyneth St
authors.initials: GS
authors.lastname: Soon
authors.affiliation: Department of Pathology, National University Health System Singapore.
authors.forename: Fredrik
authors.initials: F
authors.lastname: Petersson
mesh_terms: D014408:Biomarkers, Tumor / Q000032:analysis*; D002868:Chromosomal Proteins, Non-Histone / Q000032:analysis; D004268:DNA-Binding Proteins / Q000032:analysis; D003893:Desmin / Q000032:analysis; D058405:Desmoplastic Small Round Cell Tumor / Q000175:diagnosis* / Q000235:genetics; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D017404:In Situ Hybridization, Fluorescence; D007633:Keratins / Q000032:analysis; D008875:Middle Aged; D015514:Oncogene Proteins, Fusion / Q000235:genetics; D010386:Pelvic Neoplasms / Q000175:diagnosis* / Q000235:genetics; D000071796:SMARCB1 Protein; D014157:Transcription Factors / Q000032:analysis
chemical_list: D014408:Biomarkers, Tumor; D002868:Chromosomal Proteins, Non-Histone; D004268:DNA-Binding Proteins; D003893:Desmin; C106032:EWS1-WT1 fusion protein, human; D015514:Oncogene Proteins, Fusion; D000071796:SMARCB1 Protein; C513266:SMARCB1 protein, human; D014157:Transcription Factors; D007633:Keratins
keywords: Desmoplastic small round cell tumor; immunohistochemistry; molecular genetics