SYNOVITIS — (PVNS) is a rare but well recognized
proliferative lesion of synovial tissue. It is characterized by
hypervascular proliferative synovium containing multinucleated giant
cells, macrophages and hemosiderin. The multinucleated cells express
features of osteoclasts. Progressive nodular disease near or in the
joints limits function and may destroy adjacent bone. Although most
believe PVNS to be an inflammatory process, others consider it a benign
PVNS occurs in two forms: a diffuse form that involves the entire synovium and accounts for in the majority of cases, and a localized form that involves a discrete section of the synovium. PVNS almost always involves a single joint; the knee, hip and finger synovial structures are most commonly affected, while involvement of the shoulder, foot, and ankle is rare.
Plain radiographs may reveal well circumscribed areas of bone erosion. MRI shows a characteristic lack of signal on both T1 and T2 images which has been attributed to the presence of large amounts of hemosiderin in the synovium. This MRI signature is an important key to correct diagnosisThe principal treatment modality is resection. Although marginal excision represents the optimal treatment for localized PVNS, diffuse PVNS is more difficult to eradicate and is optimally treated with total or near total synovectomy.
The local recurrence rate among patients with localized PVNS is low, but patients with diffuse disease can have multiple recurrences and bulky disease that results in significant bone destruction. In this setting, radiation therapy to a dose of 35 to 50 Gy has been effective. In a preliminary report of the largest series of 41 patients, 40 of whom had microscopic or gross residual disease prior to radiation, 40 maintained local control at an average 77 months follow-up. These data have been corroborated by published experience from at least two other centers
Beam Radiation Therapy Enhances Local Control in
, 11 February 2009
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