Pigmented villonodular synovitis is an uncommon disease characterized by hyperplastic synovium, large effusions and bone erosions. The most common differential diagnostic are hemophilic arthropathy, synovial chondromatosis, synovial hemangioma, and synovial sarcoma. Magnetic resonance imaging is effective in distinguishing this pathology because it can reveal the deposition of hemosiderin in PVNS.

Case courtesy: Dott. Francesco Filieri