title: Angiofibroma of soft tissue with fibrohistiocytic features and intratumor genetic heterogeneity of NCOA2 gene rearrangement revealed by chromogenic in situ hybridization: a case report.
abstract: Angiofibroma of soft tissue is a recently described soft tissue tumor that is characterized by fibroblastic spindle tumor cells with arborizing capillary proliferation. Cytogenetically, it harbors a specific fusion gene involving the nuclear receptor coactivator 2 (NCOA2) gene. We report here additional new pathological and cytogenetic features. A soft tissue tumor in the left thigh of 73-year-old female was investigated. Microscopically, histiocytoid tumor cells were scattered in an edematous background with branching capillary proliferation. Immunohistochemically, we identified that the tumor cells were positive for histiocytic markers such as CD68 and CD163. Rearrangement of the NCOA2 gene was detected successfully by chromogenic in situ hybridization; however, abnormal signal patterns were observed in only a small subset of tumor cells. Unlike typical tumors with bland spindle cells, the present tumor needs to be distinguished from myxoid, dendritic and clear cell tumors. This case may suggest that angiofibroma of soft tissue is not in the center of the fibroblastic/myofibroblastic tumor group, but rather shows a fibrohistiocytic nature. We also found intratumor genetic heterogeneity, which is uncommon for a translocation-associated tumor. Therefore, careful evaluation is required to detect the gene rearrangement in this tumor entity.
authors.affiliation: Department of Pathology, Tokyo Metropolitan Cancer and Infectious Diseases Center Komagome Hospital, Tokyo, Japan.
authors.forename: Yumiko
authors.initials: Y
authors.lastname: Fukuda
authors.forename: Toru
authors.initials: T
authors.lastname: Motoi
authors.forename: Ikuma
authors.initials: I
authors.lastname: Kato
authors.forename: Masachika
authors.initials: M
authors.lastname: Ikegami
authors.forename: Nobuaki
authors.initials: N
authors.lastname: Funata
authors.forename: Rie
authors.initials: R
authors.lastname: Ohtomo
authors.forename: Shinichiro
authors.initials: S
authors.lastname: Horiguchi
authors.forename: Takahiro
authors.initials: T
authors.lastname: Goto
authors.forename: Tsunekazu
authors.initials: T
authors.lastname: Hishima
mesh_terms: D000368:Aged; D018322:Angiofibroma / Q000175:diagnosis / Q000235:genetics / Q000473:pathology*; D001706:Biopsy; D002863:Chromogenic Compounds; D005260:Female; D015321:Gene Rearrangement / Q000235:genetics*; D018740:Genetic Heterogeneity; D051677:Histiocytoma, Malignant Fibrous / Q000175:diagnosis / Q000235:genetics / Q000473:pathology*; D006801:Humans; D017403:In Situ Hybridization / Q000379:methods*; D008279:Magnetic Resonance Imaging; D051958:Nuclear Receptor Coactivator 2 / Q000235:genetics*; D012983:Soft Tissue Neoplasms / Q000175:diagnosis / Q000235:genetics / Q000473:pathology*; D013848:Thigh
chemical_list: D002863:Chromogenic Compounds; C498001:NCOA2 protein, human; D051958:Nuclear Receptor Coactivator 2
keywords: angiofibroma of soft tissue; chromogenic in situ hybridization; gene rearrangement