title: Atypical glomus tumor in the mediastinum: a case report with immunohistochemical and ultrastructural studies.
abstract: A case is reported of atypical glomus tumor occurring in the posterior inferior mediastinum of a 26-year-old woman complaining of severe back pain. The tumor was composed of atypical small, round tumor cells with scattered mitotic figures. In addition to sheet-like, diffuse proliferation of the tumor cells, some areas of the tumor contained small "glomoid" cells arranged in organoid and hemangiopericytomalike patterns. Immunohistochemically, many tumor cells were positive for muscle-type actins and a few cells were focally positive for desmin. Ultrastructural studies revealed smooth muscle features of tumor cells, that is, pinocytotic vesicles, external laminas, dense plaques, and occasional thin filaments with dense bodies. The patient remained well for 5 years and 4 months after the operation without additional radiation and chemotherapy. The tumor was diagnosed as an atypical, or low-grade malignant, glomus tumor morphologically. It seems important to recognize the presence of this type of tumor in sites other than extremities and to differentiate it from other malignant small, round cell tumors.
authors.affiliation: First Department of Pathology, University of Tokushima School of Medicine, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Hirose
authors.forename: T
authors.initials: T
authors.lastname: Hasegawa
authors.forename: K
authors.initials: K
authors.lastname: Seki
authors.forename: P
authors.initials: P
authors.lastname: Yang
authors.forename: T
authors.initials: T
authors.lastname: Sano
authors.forename: H
authors.initials: H
authors.lastname: Morizumi
authors.forename: M
authors.initials: M
authors.lastname: Tsuyuguchi
mesh_terms: D008841:Actin Cytoskeleton / Q000648:ultrastructure; D000199:Actins / Q000032:analysis; D000328:Adult; D001416:Back Pain / Q000209:etiology; D015415:Biomarkers / Q000032:analysis; D003893:Desmin / Q000032:analysis; D003937:Diagnosis, Differential; D005260:Female; D005500:Follow-Up Studies; D005918:Glomus Tumor / Q000737:chemistry* / Q000473:pathology / Q000648:ultrastructure*; D006801:Humans; D007150:Immunohistochemistry; D008479:Mediastinal Neoplasms / Q000737:chemistry* / Q000473:pathology / Q000648:ultrastructure*; D012509:Sarcoma / Q000648:ultrastructure; D014746:Vimentin / Q000032:analysis
chemical_list: D000199:Actins; D015415:Biomarkers; D003893:Desmin; D014746:Vimentin