Abstract
We treated of localized pigmented villonodular synovitis limiting a flexion of the right knee. The case was a 33-year-old male who complained of a limited flexion because of knee pain. Our clinical examinations, there was a mass in the anterolateral femorotibial joint space, restriction of knee motion (0-90°), clear yellow joint fluid. We suspected of a meniscal injury, but MR images demonstrated an intra-articular mass on the lateral side below the patella, suggesting an intra-articular tumor. We opened the joint to recognize the yellow-brown tumor originating in the synovium on the lateral side below the patella, and resected it with surrounding synovia. The pathologic diagnosis of the mass was pigmented villonodular synovitis. At present, 4 months postoperatively, the patient is free of pain, although the motion range of the knee of 0° to 135°.
