title: A case of dedifferentiated solitary fibrous tumor in the pelvis with TP53 mutation.
abstract: Solitary fibrous tumors (SFTs), initially observed in the pleura, were later found to develop in almost any extrapleural site. Dedifferentiation within SFTs was characterized only recently. We report a case of dedifferentiated SFT arising within the pelvis of a 70-year-old Japanese woman. Macroscopically, the resected tumor measured 17 × 17 × 13 cm. Histologically, the tumor displayed distinct heterologous osteosarcomatous and chondrosarcomatous components on a background of conventional SFT. Immunohistochemistry uncovered a loss of CD34 expression in the dedifferentiated area, whereas the nuclear expression of signal transducer and activator of transcription-6 (STAT6) and NGFI-A-binding protein 2 (NAB2) was maintained in both components. The p53 mutation 158 CGC > CAC (A158H) was found only in the dedifferentiated component. Furthermore, a fusion gene of NAB2(exon6)-STAT6(exon18) was detected in both the conventional and dedifferentiated components. The patient died of the disease 4 months after surgery. This case identifies a possible role of p53 dysfunction in the dedifferentiation process of SFT as reported in other sarcomas.
authors.forename: Aiko
authors.initials: A
authors.lastname: Kurisaki-Arakawa
authors.forename: Keisuke
authors.initials: K
authors.lastname: Akaike
authors.forename: Kieko
authors.initials: K
authors.lastname: Hara
authors.forename: Atsushi
authors.initials: A
authors.lastname: Arakawa
authors.forename: Michiko
authors.initials: M
authors.lastname: Takahashi
authors.forename: Keiko
authors.initials: K
authors.lastname: Mitani
authors.forename: Takashi
authors.initials: T
authors.lastname: Yao
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Saito
mesh_terms: D000368:Aged; D054337:Cell Dedifferentiation; D005260:Female; D016158:Genes, p53 / Q000235:genetics*; D006801:Humans; D009154:Mutation; D015514:Oncogene Proteins, Fusion / Q000378:metabolism; D010388:Pelvis; D054364:Solitary Fibrous Tumors / Q000235:genetics* / Q000473:pathology*
chemical_list: D015514:Oncogene Proteins, Fusion