title: Atypical pleomorphic extraosseous ewing tumor/peripheral primitive neuroectodermal tumor with unusual phenotypic/genotypic profile.
abstract: A pleomorphic undifferentiated tumor primarily located in the retroperitoneum with a phenotype compatible with an extraosseous Ewing tumor/peripheral primitive neuroectodermal tumor (ET/pPNET) pattern and unusual molecular features is described. Immunohistochemically, HBA-71 (CD99/mic2) and several neural markers were intensively expressed together with scattered cells expressing carcinoembryonic antigen (CEA). Short-term culture showed biphasic neuroblastic and epithelioid cell populations, with the latter expressing germ cell markers (CEA, alpha-fetoprotein, and the beta-subunit of chorionic gonadotrophin). Conventional cytogenetics displayed several chromosomic rearrangements, especially a complex translocation t(17,2,22,13) (q21::q11-->q33::q12-->q13::q14). These structural abnormalities were confirmed using fluorescence in situ hybridization analysis. Molecular studies revealed EWS-FEV fusion transcripts (exon 7 of the EWS gene and exon 2 of the FEV gene). In addition, a new p53 mutation not previously reported in ET/pPNET involving exon 5 codon 138: GCC to GAC (Ala/Asp) was detected. In our case, we emphasize the presence of atypical features not only from the phenotypic point of view but also at the genetic level as well as the value of detecting such markers in the differential diagnosis with other abdominal pleomorphic tumors.
authors.affiliation: Department of Pathology, Medical School, University of Valencia, Valencia, Spain. samuel.navarro@uv.es
authors.forename: S
authors.initials: S
authors.lastname: Navarro
authors.forename: R
authors.initials: R
authors.lastname: Noguera
authors.forename: A
authors.initials: A
authors.lastname: Pellín
authors.forename: Jose A
authors.initials: JA
authors.lastname: López-Guerrero
authors.forename: E
authors.initials: E
authors.lastname: Roselló-Sastre
authors.forename: A
authors.initials: A
authors.lastname: Cremades
authors.forename: A
authors.initials: A
authors.lastname: Llombart-Bosch
mesh_terms: D000328:Adult; D014408:Biomarkers, Tumor / Q000032:analysis; D002871:Chromosome Banding; D002880:Chromosomes, Human, Pair 11; D002892:Chromosomes, Human, Pair 22; D004273:DNA, Neoplasm / Q000032:analysis; D017809:Fatal Outcome; D015321:Gene Rearrangement; D016158:Genes, p53; D006801:Humans; D007621:Karyotyping; D008297:Male; D009154:Mutation; D016609:Neoplasms, Second Primary; D018242:Neuroectodermal Tumors, Primitive / Q000737:chemistry / Q000235:genetics / Q000473:pathology*; D015514:Oncogene Proteins, Fusion / Q000235:genetics; D012186:Retroperitoneal Neoplasms / Q000737:chemistry / Q000235:genetics / Q000473:pathology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012512:Sarcoma, Ewing / Q000737:chemistry / Q000235:genetics / Q000473:pathology*; D012983:Soft Tissue Neoplasms / Q000737:chemistry / Q000235:genetics / Q000473:pathology*; D014178:Translocation, Genetic; D014407:Tumor Cells, Cultured
chemical_list: D014408:Biomarkers, Tumor; D004273:DNA, Neoplasm; C419546:EWS-FEV fusion protein, human; D015514:Oncogene Proteins, Fusion