Synovitis, Pigmented Villonodular

**Definition:** Diffuse outgrowth arising from the SYNOVIAL MEMBRANE; SYNOVIAL BURSA; or TENDON sheath around the joint cavity, with extension to surrounding soft tissue. It is characterized by pigmented HEMOSIDERIN-containing MACROPHAGES; FOAM CELLS; and multinucleated GIANT CELLS. It usually occurs in the hands and feet, and around large joints, such as in the ankle and knee joints.

**Tree numbers:** - C04.557.450.565.380.690.500 - C05.550.870.445.500 - C05.651.869.762.500

**Synonyms:** - Diffuse Tenosynovial Giant Cell Tumor