title: Proximal-type epithelioid sarcoma of the perineum: calling attention of urologists.
abstract: A subcutaneous mass in the perineum of a middle-aged man was excised and pathologically diagnosed at first as 'undifferentiated carcinoma' of unknown origin, which recurred 2 years later without any metastasis. Further histological evaluation ultimately established a correct diagnosis of 'proximal-type epithelioid sarcoma', a variant of rare epithelioid sarcoma. This type of tumor may confuse pathologists because its histological characteristics resemble undifferentiated carcinoma or malignant rhabdoid tumor. Frequent immunoreactivity of CD34, in addition to expression of keratins, epithelial membrane antigen and vimentin, provides strong support for the diagnosis of this rare neoplasm. Urologists should be aware that this sarcoma commonly occurs in the genital regions.
authors.affiliation: Department of Urology, Kamo Hospital, Toyota, Japan. uropatho@ybb.ne.jp
authors.forename: Atsuya
authors.initials: A
authors.lastname: Hikosaka
authors.forename: Kenji
authors.initials: K
authors.lastname: Yamada
authors.forename: Keiji
authors.initials: K
authors.lastname: Fujita
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Iwase
authors.forename: Toyohiro
authors.initials: T
authors.lastname: Tada
mesh_terms: D014408:Biomarkers, Tumor / Q000378:metabolism; D003131:Combined Modality Therapy; D003937:Diagnosis, Differential; D005500:Follow-Up Studies; D005834:Genital Neoplasms, Male / Q000175:diagnosis* / Q000378:metabolism / Q000628:therapy; D006801:Humans; D007633:Keratins / Q000378:metabolism; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010502:Perineum; D012509:Sarcoma / Q000175:diagnosis* / Q000378:metabolism / Q000628:therapy; D014057:Tomography, X-Ray Computed; D014746:Vimentin / Q000378:metabolism
chemical_list: D014408:Biomarkers, Tumor; D014746:Vimentin; D007633:Keratins