[Electron microscopic examinations on foam cells in pigmented villonodular synovitis (PVS) (author's transl)]

The pathologic and histologic features of 17 cases of pigmented villonodular synovitis and bursitis are described. Similar lesions were induced in rabbit knee joints by injection of hypercholesterolaemic serum. A therory is presented that the inflammatory reaction is induced by release of cholesterol esters and crystals from foam cells in a manner similar to crystal-induced synovitis. It is theorized that a disturbance of cholesterol metabolism is responsible for the development of foam cells.