title: Fine needle aspiration cytology of primary proximal-type epithelioid sarcoma of the perineum: a case report.
abstract: BACKGROUND
  Epithelioid sarcoma is a malignant soft tissue tumor of unknown histogenesis. We describe the cytologic findings in a case of primary proximal-type epithelioid sarcoma of the perineum and results of an immunofluorescence analysis of rhabdoid cells from this tumor. To the best of our knowledge, the 3-color immunofluorescence features of proximal-type epithelioid sarcoma have never before been reported.
  
  
  METHODS
  An 8-cm-diameter mass with a 2.5-cm ulcer was found in the perineum of a 36-year-old man. After excision of the tumor, histopathologic examination of the resected specimen suggested a diagnosis of proximal-type epithelioid sarcoma. Fine needle aspiration cytology showed numerous rhabdoid cells with globular intracytoplasmic inclusions. A few isolated cells and polygonal cells were also observed in the smears. Three-color immunofluorescence analysis indicated that the intracytoplasmic inclusions in the rhabdoid cells were positive for cytokeratin, vimentin and CD34. The cytoplasmic staining pattern differed between rhabdoid and epithelioid sarcoma cells.
  
  
  CONCLUSIONS
  Immunofluorescent staining of rhabdoid cells from a primary perineal proximal-type epithelioid sarcoma revealed an uneven distribution of cytokeratin in intracytoplasmic inclusions, with the highest concentration at the periphery of the inclusions.
authors.affiliation: Department of Pathology, Showa University Fujigaoka Hospital, Fujigaoka, Yokohama, Japan. kachu@mx2.ttcn.ne.jp
authors.forename: Katsuhide
authors.initials: K
authors.lastname: Ikeda
authors.forename: Genshu
authors.initials: G
authors.lastname: Tate
authors.forename: Takao
authors.initials: T
authors.lastname: Suzuki
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Mitsuya
mesh_terms: D000328:Adult; D044963:Biopsy, Fine-Needle; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D010502:Perineum; D012509:Sarcoma / Q000175:diagnosis / Q000473:pathology*