This information is provided by the National Institutes of Health (NIH) Genetic and Rare Diseases Information Center (GARD).
Pigmented villonodular synovitis (PVNS) is a disease in which the tissue lining the joints and tendons in the body (synovium) grows abnormally. It is characterized by a noncancerous mass or tumor. There are two types of PVNS: the local or nodular form (where the tumor involves the tendons that support the joint, or in one area of the joint) and the diffuse form (where the entire lining of the joint is involved). Symptoms might include: pain, limitation of movement, and locking of the joint. In some cases, the normal joint structure can be destroyed. The knee is most commonly affected by this condition, though it can occur in other joints such as the hip, shoulder, elbow, ankle, wrist, and rarely the jaw. The average age of diagnosis for this condition is 35 years. The cause of PVNS is unknown. Treatment involves surgery to remove the tumor and damaged portions of the synovium.
For more information, visit GARD.