Locking of the knee caused by localized pigmented villonodular synovitis: a case report.

Pigmented villonodular synovitis (PVS) occurs in two forms: diffuse PVS and localized pigmented villonodular synovitis. In this report, a 40-year-old woman presented with a history of recurrent episodes of knee locking and pain. Arthroscopy revealed a nodular pedunculated mass occupying the area anterior to the intercondylar notch of the femur. Histological examination of the tissue confirmed the diagnosis of PVS. After surgery, the patient's symptoms of pain and recurrent locking promptly resolved.