Pigmented Villonodular Synovitis of the great toe metatarsophalangeal joint (case report)

Background: Pigmented villonodular synovitis is a tumor that arises from the synovial membrane of the joint or tendon sheaths. Two main forms include a diffuse form that involves the whole synovial lining of a joint, bursa, or tendon sheath, and a less common localized form. The diffuse form typically involves the large joints, while the localized one typically occurs around the small joints of the hands and feet. Usually involving the knee joint, the occurrence of pigmented villonodular synovitis in the foot, especially in the metatarsophalangeal joint of the great toe, is very rare, and is therefore often mistaken for other foot pathologies. Although it seems histopathologically benign, it has a known tendency to recur after surgery.Case report: Here, we report a 42 year old woman who had experienced pain in the right great toe for 1.5 years. She was treated conservatively with shoe modification and NonSteroidal Anti-Inflammatory Drugs, and two injections of Corticosteroid.Results: The failure of long-term conservative therapy and the bony erosion revealed in her radiograph led us to surgically excise the lesion of the first metatarsophalangeal joint. Histopathological examination revealed the diagnosis of pigmented villonodular synovitis. For the 18 months following surgery, she had no complaint except minimal pain in her toe after activity. No sign of recurrence was observed either clinically or radiologically.Conclusion: We conclude that pigmented villonodular synovitis should be noted in the differential diagnosis of chronic monoarticular synovitis in order to provide an earlier diagnosis and more effective treatment.