Pigmented Villonodular Synovitis (PVNS)

Introduction

Pigmented Villonodular Synovitis (PVNS) is a rare joint condition where the lining of a joint, called the synovium, grows too much and becomes thickened. This extra tissue can form nodules (lumps) or villi (finger-like projections) inside the joint. Over time, this abnormal growth can damage the cartilage and bone in the joint. PVNS usually affects large joints such as the knee or hip, but it can also develop in smaller joints like the ankle or shoulder. The exact cause of PVNS isn’t fully understood, but it is thought to be related to abnormal cell growth in the synovium.

Symptoms of PVNS

PVNS often develops slowly, and its symptoms can look a lot like arthritis. People with PVNS may notice swelling, stiffness, and aching in the joint. The joint may feel warm or tender, and in some cases it can lock or give way. Because the synovium grows and produces extra fluid, the joint can feel swollen and painful, making it harder to move. If left untreated, the extra tissue can wear away the cartilage, leading to arthritis-like damage inside the joint.

How PVNS is Diagnosed

To diagnose pigmented villonodular synovitis, a doctor will start by asking about symptoms, such as how long the joint has been swollen and painful, and whether the symptoms come and go. During the exam, the doctor will check for swelling, warmth, range of motion, and tenderness. Imaging tests are very important for diagnosis. X-rays may show joint damage in advanced cases, but MRI scans are usually the most helpful because they can show the abnormal synovial tissue inside the joint. PVNS creates symptoms that may be quite similar to other forms of arthritis. Therefore, a sample of the tissue (biopsy) is often needed to confirm the diagnosis.

Treatment of PVNS

Treatment for PVNS depends on the severity of symptoms and how much damage the joint has. The main goal is to remove or reduce the abnormal synovial tissue to protect the joint. Non-surgical treatments may include medications or injections to help reduce inflammation and relieve pain, but these usually do not cure PVNS. In some cases, radiation therapy may be used to shrink the abnormal tissue, though this is less common.

Surgery for PVNS

Surgery is the most common treatment for PVNS, especially when the condition is causing significant pain, swelling, or joint damage. The surgery, called a synovectomy, involves removing the abnormal synovial tissue from the joint. This can be done with traditional open surgery or minimally invasive arthroscopic surgery, depending on the joint and how much tissue is involved. In severe cases, if the joint is badly damaged, joint replacement surgery may be considered.

Prognosis and Long-Term Outlook for PVNS

With proper treatment, many people with PVNS do well, but the condition can sometimes come back even after surgery. Regular follow-up and imaging may be needed to monitor the joint. If PVNS is not treated, it can lead to chronic pain, arthritis, and permanent joint damage. Early diagnosis and treatment are important to help preserve joint function and prevent long-term complications.

Edited by Stephen Pinney MD, September 15th 2025.