Pigmented villonodular synovitis of the temporomandibular joint.

Pigmented villonodular synovitis ( PVNS ) is a benign disease of unknown etiology arising from the synovial membranes of joints, bursae, and tendon sheaths. Though histologically benign, it is a very aggressive lesion, capable of bone destruction and widespread infiltration of surrounding tissues. It is a rare disease, usually confined to large joints, particularly the knee. Its propensity for recurrence is emphasized in this report. Involvement of the temporomandibular joint (TMJ) is unusual. It most commonly presents in the TMJ region as a left pre-auricular mass. Symptoms of TMJ dysfunction are usually present, but may be subtle. These may consist of painful mastication, clicking, trismus, malocclusion, and deep pain in the TMJ. Radiological evidence of bone destruction is frequently present, and together with the pre-auricular mass, should suggest the diagnosis. Surgical excision is the preferred mode of treatment. While cosmesis is a consideration, radical excision, including involved bone, is mandatory to prevent recurrence. The effect of radiotherapy on this disease in the head and neck region is documented.