Sinovitis villonodular pigmentada focal como diagnóstico diferencial de monoartritis de rodilla

Pigmented villonodular synovitis (PVNS) is a benign synovial proliferation associated with hemosiderin deposits, which originates in joints, bursa or tendon sheaths. The knee is the joint most commonly affected (80% of cases), and less frequently it can affect the shoulder, ankle and elbow. Magnetic Resonance Imaging (MRI) is used to detect PVNS, and histological analysis is used to confirm the diagnosis. We describe the case of a patient with monoarthritis of the left knee, who after multiple biopsy studies, it was found to be compatible with PVNS.