Clinical Image: Pigmented villonodular synovitis of the knee

Authors


The patient, a 37-year-old man, presented with pain and swelling in his left knee. Radiography of the knee joint revealed a soft tissue mass. The mass was shown to be hypointense on both T1- and T2-weighted magnetic resonance imaging sequences. Fast low-angle shot gradient-echo images showed significant loss of signal, consistent with hemosiderin deposition. Based on the hemosiderin deposits, villonodular soft tissue mass (arrowheads), and multiple bone erosions (arrows), pigmented villonodular synovitis was diagnosed. 1

Illustration 1.

Clinical Image: Pigmented villonodular synovitis of the knee

Ancillary