Atypical Presentation of Pigmented Villonodular Synovitis: A Case Report.

Pigmented villonodular synovitis is a rare, disabling disease that usually presents in young adults. Here, the authors present a unique case of pigmented villonodular synovitis in a 60-year-old female diagnosed 20 years after the initial presentation. The patient presented with a complaint of knee pain consistent with osteoarthritis.