Pigmented Villonodular Synovitis

Summary
Description

Pigmented villonodular synovitis (PVNS) is a locally aggressive synovial tumor. There are two forms of PVNS: diffuse and nodular. Nodular occurs most commonly in the hands and diffuse is found most commonly in the knee. PVNS may also occur in the hips and ankle.

People and Age
PVNS has the highest prevalence during the third and fourth decades and it affects males and females equally.
Symptoms and Presentation
It presents as a painless or mildly painful joint with swelling.
Brief description of the xray
The radiological appearance of PVNS depends on the location.
Brief desc of tx
Treatment of PVNS is surgical excision.
Tumor Type
Benign or Malignant
Most Common Bones
Tumor behavior
Complete Information on this Tumor
Introduction and Definition

Pigmented villonodular synovitis (PVNS) is a locally aggressive synovial tumor. There are two forms of PVNS: diffuse and nodular. Nodular occurs most commonly in the hands and diffuse is found most commonly in the knee. PVNS may also occur in the hips and ankle.

Incidence and Demographics
PVNS has the highest prevalence during the third and fourth decades and it affects males and females equally.
Symptoms and Presentation

It presents as a painless or mildly painful joint with swelling.

X-Ray Appearance and Advanced Imaging Findings
The radiological appearance of PVNS depends on the location. A nodule in the hand may have soft tissue swelling and bone erosion on plain x-ray. The knee usually only has a soft tissue mass but bone erosion or cysts will be present in tighter joints like the hip, elbow, ankle or wrist. The joint space is
usually preserved and there may be an effusion. CT scan is able to pick up the hemosiderin and demonstrates the extent of the synovial involvement as well as bone erosion and cysts. Hemosiderin appears as low or absent signal on both T1 and T2 weighted images.
Histopathology findings
On gross examination, the diffuse form of PVNS is a tan mass of villi and folds of synovium. The lesion may be sessile or have several pedunculated nodules. Bony invasion through the joint capsule is possible. The local form of PVNS is a pedunculated firm nodule.
Microscopically, PVNS is characterized by synovial cell hyperplasia both on the surface and below the synovium. Also present are scattered giant cells, hemosiderin and foam cells. The location of the polyhedral cells below the synovial membrane suggests that perhaps the cell of origin is a fibrohistiocyte. The pathologic differential includes hemosiderotic synovitis, rheumatoid arthritis and synovial chondromatosis.
Treatment Options for this Tumor
Treatment of PVNS is surgical excision.
Outcomes of Treatment and Prognosis
Recurrences are common due to the difficulty of complete surgical excision.
Suggested Reading and Reference
Bullough, Peter, Orthopaedic Pathologv (third edition), Times Mirror International Publishers Limited, London, 1997.

Huvos, Andrew. Bone Tumors: Diagnosis. Treatment and Prognosis, W.B.
Saunders, Co., 1991.

Bravo, SM et al., Pigmented Villonodular synovitis, Radiologic Clinics of North America, 34(2):311-325, March, 1996.

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