Pigmented villonodular synovitis.

Pigmented villonodular synovitis (PVNS) is a benign disease that rarely undergoes malignant transformation. There are two types of disease: localized (nodular tenosynovitis) and di used (pigmented villonodular synovitis/tenosynovitis) with intra- or extra-articular locations. The second one is limited to synovium of the burse (PVNB) or tendon sheath (PVNTS).