Atricle on PVNS

Tumor biology and incidence

Pigmented villonodular synovitis (PVNS) is a condition of the synovial membrane that is characterized by the presence of inflammation and hemosiderin deposition in the synovium. Early descriptions focused on PVNS as a neoplastic process due to unrelenting growth pattern, capacity to erode surrounding boneand joint tissue, and high recurrence rate after resection. Later reports described the condition as an inflammatory process. Controversy still surrounds this area.

Two disease entities exist, the localized and diffuse forms. While both are virtually identical histologically, they vary significantly with respect to clinical presentation, prognosis, and response to treatment. Keeping this in mind, the two diseases probably exist along a continuum of a single disease process.

The estimated incidence of PVNS is 1.8 per million, with the diffuse form being the more common.

Etiology

The etiology of PVNS is still unknown:

Inflammatory versus Neoplastic Origin-
Histologic samples have tested positive for markers of chronic inflammation, while excess iron has been seen to transform synoviocytes and fibroblasts into cells with macrophage-like characteristics. Reports have linked the condition to trisomy 7 and have identified the presence of clonal DNA. In addition, literature exists that describes potential malignant transformations and metastasis.

Mechanical versus metabolic sources of trauma-

Mechanical trauma causing recurrent local hemorrhage into the joint is seen in hemophiliacs. These individuals suffer from progressive erosive arthropathies, with similar lobular synovitis and hemosiderin deposition. However, hemophiliacs lack the lipid laden histiocytes and giant cells that are considered classic indications of PVNS. Trauma has only been associated in less than one-third of the cases of PVNS. Altered local metabolic environment creates insults to the synovium leading to chronic inflammation.

Age

PVNS often appears in the third and fourth decades of life.

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This is the first place I read that PVNS can lead to cancer & metastasis. Prof. Bikles said that there is absolutely no connection or chance of it ever turning into cancer. He also said that it has nothing to do with the NF trauma, and this article says that it can be connected to a traumatized region.

Here is the full article:

http://www.orthopaedia.com/display/Main/Pigmented+villonodular+synovitis+(PVNS)

Opinions? Insights? (like my color choices?)