title: Pigmented villonodular synovitis of the temporomandibular joint.
abstract: A 39-year-old woman had a large asymptomatic left parotid mass that she had apparently not noticed. The clinical appearance suggested a parotid tumor. Aspirated tissue revealed numerous giant cells, histiocytes, and hemosiderin pigment. At surgical exploration a tumor was found deep to the facial nerve involving the temporomandibular joint, which had a brown-stained roughened synovial membrane. The resected specimen histologically was a proliferative lesion composed of epithelioid histiocytes, spindle cells, and multinucleated giant cells. The appearance was typical of the family of lesions that includes pigmented villonodular synovitis, bursitis, and tenosynovitis (giant cell "tumor" of tendon sheath). In view of the origin from the temporomandibular joint, reinforced by a characteristic radiologic appearance, we interpret this as a case of pigmented villonodular synovitis. This is the fifth case reported from this site.
mesh_terms: D000328:Adult; D001706:Biopsy; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D010307:Parotid Neoplasms / Q000175:diagnosis*; D013585:Synovitis / Q000175:diagnosis*; D013586:Synovitis, Pigmented Villonodular / Q000175:diagnosis* / Q000601:surgery; D013704:Temporomandibular Joint / Q000601:surgery