title: Sequence confirmation of the EWS-WT1 fusion gene transcript in the peritoneal effusion of a patient with desmoplastic small round cell tumor.
abstract: Desmoplastic small round cell tumor (DSRCT) is a rare undifferentiated neoplasm. The prognosis is poor, even if therapy is instituted promptly, and thus it is important to differentiate it from other histologically and cytologically similar-looking malignancies of the young adult. We present a case of DSRCT in a 17-yr-old male with disseminated peritoneal disease and peritoneal effusion. The cytology sample showed a malignant small round cell tumor, the classical cytological features of DSRCT, and immunohistochemistry performed in the prepared cell block exhibited an antibody expression profile in keeping with DSRCT. Further material from the effusion was prepared for RNA extraction, following which a reverse-transcriptase polymerase chain reaction (RT-PCR) and sequencing of the t(11;22)(p13;q11 or q12) were carried out. The result showed the presence of the reciprocal translocation and thus confirmed the diagnosis of DSRCT. This case shows how molecular techniques (including sequencing) can be applied to cytology in clarifying and confirming certain difficult diagnosis of undifferentiated neoplasms, DSRCT in this particular case.
authors.affiliation: Molecular Diagnosis Centre, Department of Laboratory Medicine, National University Hospital, Singapore.
authors.forename: L L
authors.initials: LL
authors.lastname: Chiu
authors.forename: E S C
authors.initials: ES
authors.lastname: Koay
authors.forename: N H
authors.initials: NH
authors.lastname: Chan
authors.forename: M
authors.initials: M
authors.lastname: Salto-Tellez
mesh_terms: D000293:Adolescent; D001201:Ascites / Q000175:diagnosis / Q000235:genetics / Q000378:metabolism; D001202:Ascitic Fluid / Q000175:diagnosis / Q000235:genetics*; D001483:Base Sequence; D014408:Biomarkers, Tumor / Q000032:analysis; D018288:Carcinoma, Small Cell / Q000737:chemistry / Q000235:genetics* / Q000473:pathology; D006801:Humans; D008297:Male; D008969:Molecular Sequence Data; D015514:Oncogene Proteins, Fusion / Q000235:genetics*; D051789:Proto-Oncogene Protein c-fli-1; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012334:RNA, Neoplasm / Q000032:analysis; D034802:RNA-Binding Protein EWS; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017423:Sequence Analysis, RNA; D012983:Soft Tissue Neoplasms / Q000737:chemistry / Q000235:genetics* / Q000473:pathology; D014157:Transcription Factors / Q000235:genetics*; D014178:Translocation, Genetic
chemical_list: D014408:Biomarkers, Tumor; C106031:EWS-FLI fusion protein; D015514:Oncogene Proteins, Fusion; D051789:Proto-Oncogene Protein c-fli-1; D012333:RNA, Messenger; D012334:RNA, Neoplasm; D034802:RNA-Binding Protein EWS; D014157:Transcription Factors