title: Pigmented villonodular synovitis presenting as a subcutaneous mass at the knee.
abstract: We describe a 45-year-old man who developed a painful mass about his knee. Magnetic resonance imaging demonstrated a well defined lesion, and biopsy confirmed a diagnosis of pigmented villonodular synovitis. Our case exemplifies a primary synovial process presenting as a subcutaneous tumor. Such diagnostic possibilities, although rare, should be more widely known.
authors.affiliation: Department of Radiology, School of Medicine, University of Missouri, Columbia 65212.
authors.forename: R
authors.initials: R
authors.lastname: Cope
authors.forename: P S
authors.initials: PS
authors.lastname: Apostoles
authors.forename: A J
authors.initials: AJ
authors.lastname: Pearl
authors.forename: L E
authors.initials: LE
authors.lastname: Spollen
mesh_terms: D003937:Diagnosis, Differential; D006801:Humans; D007717:Knee / Q000473:pathology; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D012983:Soft Tissue Neoplasms / Q000175:diagnosis* / Q000473:pathology; D013586:Synovitis, Pigmented Villonodular / Q000175:diagnosis* / Q000473:pathology