What is the definition of Pigmented Villonodular Synovitis?
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.
What are the alternative names for Pigmented Villonodular Synovitis?
- Localized pigmented villonodular synovitis
- Diffuse pigmented villonodular synovitis
- Tenosynovial giant cell tumors
- Diffuse-type GCT
- Diffuse-type giant cell tumor
- Tenosynovial giant cell tumor
What are the causes for Pigmented Villonodular Synovitis?
The exact cause of pigmented villonodular synovitis (PVNS) is unknown. Some doctors believe that it is similar to arthritis, arising from swelling (inflammation) of the joint tissue. Others believe it develops like a tumor, caused by cells growing and multiplying more quickly than usual. The association between a history of trauma and the development of PVNS is unclear. One study found that 56% of individuals with PVNS had a history of previous trauma, while other studies have found a much lower incidence.
There have been studies suggesting that PVNS could be caused by specific genetic changes in the cells lining the joint. More studies are needed to research this association.
What are the current treatments for Pigmented Villonodular Synovitis?
Pigmented villonodular synovitis is first treated with surgery to remove as much of the abnormal tissue growth as possible. The type of surgery depends on the location and extent of the disease within the joint. Radiation therapy is sometimes used to treat this condition if surgery is not an option, or if the condition returns (recurs) after an initial surgery.
How is Pigmented Villonodular Synovitis diagnosed?
Pigmented villonodular synovitis (PVNS) is diagnosed via physician examination, imaging studies, and sometimes surgical procedures. Imaging studies commonly used include: X-ray, MRI, and CT scan. MRI findings are diagnostic in more than 95% of patients. CT scan findings are additionally often diagnostic, though they might not show the extent of the disease.
Other methods that might be utilized in the diagnostic process include joint aspiration, in which a needle is used to remove fluid from the joint and a biopsy, in which a small operation is completed to obtain a tissue sample.