[Pigmented villonodular synovitis].

Pigmented villonodular synovitis (PVNS) is a destructive proliferative tumoroid disease of the synovial sheath of the joints, bursae, and tendon. The microscopic pattern of PVNS is characterized by mosaicism: compact cell zones alternate with loose few-celled fields. The synovial sheath is hyperplastic; its stroma exhibits hemosiderin and siderophages, as well as histiocytes, lymphocytes, multinucleated giant osteoclasts, foamy and synoviocyte-like cells. Proliferation with destructive growth was noted in PVNS. A distinction is made between focal and diffuse, intraarticular and extraarticular forms of the disease. Early diagnosis of the disease favors effective treatment and prevention of soft tissue and bone destruction and reduces the risk of recurrences.