Radiologic case study. Pigmented villonodular synovitis.

Pigmented villonodular synovitis is a benign, locally aggressive disorder characterized by a unique clinical radiographic, and histopathologic presentation. While it is considered to be a rare disorder, a delay in diagnosis and treatment can potentially result in severe disruption of joint function due to subchondral invasion. Once the diagnosis is confirmed, treatment should consist of complete synovectomy. Recurrence is common, but malignant transformation is rare. The etiology of PVNS is still unknown, and perhaps its future discovery will assist in the definitive treatment of this disorder.