title: Intraarticular synovial sarcoma.
abstract: A 43-year-old man presented with decreased range of motion in his left knee and a painful medial joint mass that was grossly visible. Arthroscopy demonstrated a mobile, flat mass 3 cm in diameter in the knee joint that seemed to be loosely tethered to the synovium. The mass was excised, and light microscopic examination demonstrated a biphasic synovial sarcoma. There was no transition with the attached normal synovium. Immunohistochemically, the epithelial component was intensely positive for epithelial membrane antigen and cytokeratins (CAM 5.2 and AE 1/AE 3), and the spindle cell component was focally positive for these markers. The patient has no evidence of disease 9 years after only local excision. Although the term synovial sarcoma suggests a relationship to normal synovium, only rarely has truly intraarticular disease been reported.
authors.affiliation: Department of Pathology, University of Virginia Health Sciences Center, Charlottesville 22908.
authors.forename: C D
authors.initials: CD
authors.lastname: McKinney
authors.forename: S E
authors.initials: SE
authors.lastname: Mills
authors.forename: R E
authors.initials: RE
authors.lastname: Fechner
mesh_terms: D000328:Adult; D002358:Cartilage, Articular; D006801:Humans; D007150:Immunohistochemistry; D007633:Keratins / Q000032:analysis; D007719:Knee Joint / Q000473:pathology; D008297:Male; D008562:Membrane Glycoproteins / Q000032:analysis; D018396:Mucin-1; D009372:Neoplasms, Connective Tissue / Q000737:chemistry / Q000175:diagnosis / Q000473:pathology*; D013584:Sarcoma, Synovial / Q000737:chemistry / Q000175:diagnosis / Q000473:pathology*
chemical_list: D008562:Membrane Glycoproteins; D018396:Mucin-1; D007633:Keratins