Pigmented villonodular synovitis of the subtalar joint: a case report.

Pigmented villonodular synovitis (PVNS) is a slowly progressive, proliferative disorder of synovial tissue. It is a disease of uncertain etiology characterized by villus and/or nodular overgrowths in the synovium-lined joints, tendon sheaths, and bursae. As a joint problem, PVNS most frequently affects the large joints of the lower extremity with 80% of the cases involving the knee.’ Classically it has been described to present as a monoarticular arthritis that affects adults in the third or fourth PVNS has also been reported to occur in ~hi1drenl.l~ and in multiple joints of a single patient.13.14 Virtually any joint can be affected. Below the knee, PVNS is most frequently associated with the tibiotalar joint or the tendon sheaths surrounding the foot. Rare cases have also been identified in the calcaneocuboid and the first metatarsophalangeal j~int.~.’,~’ We report a case of PVNS of the subtalar joint. To the best of our knowledge, no case has been reported previously in the English literature. Seltzer et al.,” in an article describing the use of computed tomography (CT) to evaluate the hindfoot, mentions a lesion of the subtalar joint caused by PVNS. However, no description is given of the clinical presentation, operative findings, histological findings, or outcome.