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 of PVNS is surgical excision.
Recurrences are common due to the difficulty of complete surgical excision.
Treatment and Prognosis , W.B. Saunders, Co., 1991.