What Is Pigmented Villonodular Synovitis?
Pigmented villonodular synovitis is a rare disease in which the tissue lining the joints and tendons grows abnormally . This tissue, known as synovium, normally covers certain joints and tendons in the body and produces a fluid, called synovial fluid, that lubricates the joints. In pigmented villonodular synovitis, this tissue grows abnormally, forming a tumor. Pigmented villonodular synovitis cannot spread to other parts of the body and thus is not considered a cancer but it can cause local damage in the joint.
Symptoms of both types, diffuse and localized pigmented villonodular synovitis, include joint pain, warmth, swelling, stiffness, and instability.
Treatment involves directly addressing abnormal tissue growth via surgical removal, possible joint repair or replacement, as well as radiation or other targeted therapies .
You should visit your primary care physician who will likely coordinate care with a muscle and bone specialist (orthopedic surgeon). The treatment for PVNS is surgery and radiation therapy.
How common is pigmented villonodular synovitis?
Symptoms that never occur with pigmented villonodular synovitis:
- Knee instability
Pigmented villonodular synovitis is also known as
- Tenosynovial giant cell tumor
- Localized pigmented villonodular synovitis
- Diffuse pigmented villonodular synovitis
Pigmented Villonodular Synovitis Symptoms
There are two main types of pigmented villonodular synovitis. In one form, the diffuse form, the entire synovial lining of the joint is affected. This is the form seen in the majority of cases of pigmented villonodular synovitis. In the second form, the localized form, only discrete parts of the synovial lining of the joint are affected. Symptoms that can be seen in both forms of pigmented villonodular synovitis include:
- Joint pain: Pigmented villonodular synovitis almost always affects just one joint. The knee and the foot are the most common joints affected, although less commonly, pigmented villonodular synovitis can affect the shoulder, wrist, hand, or hip. The pain usually develops gradually and may come and go.
- Joint warmth and swelling: These are symptoms of an inflammatory process occurring in the joint.
- Joint stiffness and/or limited range of motion in the affected joint: You may feel the affected joint “catching” or “locking” when you move it back and forth.
- Joint instability: In more severe cases of pigmented villonodular synovitis, you may develop instability in the affected joint. This can occur if the pigmented villonodular synovitis causes substantial damage to the joint structures. If this occurs, the joint may not be able to bear weight as it normally would.
Pigmented Villonodular Synovitis Causes
The specific cause of pigmented villonodular synovitis is not known, however, the following are believed to be factors. Pigmented villonodular synovitis is usually seen in middle-aged individuals, with an average age of 35 years at diagnosis .
Specific genetic mutations in the synovial cells
Some studies suggest that specific genetic mutations in the synovial cells could lead to changes that cause the cells to grow abnormally, similar to what happens in other tumors . However, studies have not definitively shown that this is the case.
Inflammation of the joint
Inflammation in the joint could cause the synovial cells to grow abnormally, resulting in the development of pigmented villonodular synovitis. This process could be similar to what is seen in arthritis, which is an inflammation of the joint.
Injury to the joint
Injury to a joint could predispose a person to develop pigmented villonodular synovitis. Some studies have shown that up to half of people with pigmented villonodular synovitis had a history of injury to that joint .
Treatment Options and Prevention
The definitive way to treat pigmented villonodular synovitis is with surgery to remove as much of the abnormal tissue growth as possible, however, recurrence rates vary . In addition, there are other treatment options that may be considered when surgery is not possible or does not remove all of the abnormal tissue.
Surgery to remove the abnormal tissue growth and repair the joint
The main way to treat pigmented villonodular synovitis is with a surgical procedure to remove as much of the abnormal tissue growth as possible and repair any structures in the joint that may be damaged. There are a number of ways that this can be done. In arthroscopy, the surgeon makes a few small incisions near the joint and inserts cameras and surgical instruments into the joint space. Using the surgical instruments, the surgeon can remove any abnormal tissue growth. In some cases, especially if the pigmented villonodular synovitis is of the diffuse form, the surgeon may need to use an open surgery, which involves making a larger incision and directly removing any abnormal tissue growth.
Surgery to replace the joint
If the pigmented villonodular synovitis has caused substantial damage to the joint, the best option may be to remove the damaged joint and replace it with a prosthetic joint. In this procedure, the damaged joint is removed and replaced with a prosthetic joint made of metal, plastic, or ceramic. This will also usually prevent the tumor from returning since the synovial lining has been removed.
Radiation therapy to the joint
In some cases, radiation therapy can be applied to the joint to shrink the abnormal tissues. This can be used in cases where surgery is not an option, or after surgery to remove any remaining abnormal tissues and reduce the risk of recurrence. Radiation therapy can either be applied using a beam that is directed from the outside of the skin into the affected joint, or it can be applied using a radioactive liquid that is injected into the joint using a needle.
Targeted biopharmaceutical medications to treat the tumor
In some cases of pigmented villonodular synovitis, targeted biopharmaceutical medications (“biologics”) may be an option. These medications target specific molecular targets involved in the growth and development of the tumor. One example is infliximab (Remicade), a biologic medication that targets a molecule involved in inflammation. Other examples include imatinib (Gleevec), sunitinib (Sutent), sorafenib (Nexavar), and nilotinib (Tasigna), all of which inhibit a target involved with inflammation that may be over-activated in pigmented villonodular synovitis. These medications are currently still being studied for the treatment of pigmented villonodular synovitis, and so may only be available in some treatment centers.
When to Seek Further Consultation
If you develop any symptoms of pigmented villonodular synovitis, such as joint pain or swelling, joint stiffness, or joint instability, you should go to your doctor. Your doctor can perform an examination and order imaging tests to determine if you have pigmented villonodular synovitis and then offer the appropriate treatments.
Questions Your Doctor May Ask to Diagnose
To diagnose this condition, your doctor would likely ask about the following symptoms and risk factors.
- How would you explain the cause of your knee pain?
- Is your knee pain constant or come-and-go?
- Is your knee pain getting better or worse?
- How severe is your knee pain?
- How long has your knee pain been going on?
The above questions are also covered by our A.I. Health Assistant.
- Pigmented Villonodular Synovitis. American Academy of Orthopaedic Surgeons: OrthoInfo. November 2014. OrthoInfo Link
- Pigmented villonodular synovitis. Genetic and Rare Diseases Information Center. Updated April 5, 2016. GARD Link
- Xie GP, Jiang N, Liang CX, et al. Pigmented villonodular synovitis: a retrospective multicenter study of 237 cases. PLoS One. 2015;10(3):e0121451. Published March 23, 2015. NCBI Link
- Ma X, Shi G, Xia C, Liu H, He J, Jin W. Pigmented villonodular synovitis: a retrospective study of seventy five cases (eighty one joints). Int Orthop. 2013;37(6):1165–1170. NCBI Link
- Verspoor FG, Zee AA, Hannink G, Van der geest IC, Veth RP, Schreuder HW. Long-term follow-up results of primary and recurrent pigmented villonodular synovitis. Rheumatology (Oxford). 2014;53(11):2063-70. PubMed Link