One hundred seventeen patients with 118 fibrous xanthomas of synovium were studied.
Ninety-one of these xanthomas were in the fingers. The most common site was the dorsal surface of the distal joints of the index, long, ring, and little fingers. Fourteen tumors were found in the knee joint; four each, in the hand, wrist, and foot; and one tumor was in the hip joint.
There was clinical or roentgenographic evidence that the joint from which the tumor arose or the joint nearest the tumor was damaged by traumatic or idiopathic degenerative joint disease in fifty-three patients.
All of the tumors in this study were locally excised; 17 per cent recurred one or more times. All of the recurrences were in the fingers. From our material it could not be determined whether or not incomplete excision of the tumors accounted for these recurrences.
Fibrous xanthoma, xanthoma due to disturbed systemic lipid metabolism, tumors of histiocytes, pigmented villonodular synovitis, and synovitis due to traumatic or idiopathic degenerative joint disease were compared with respect to some of their clinical and pathological characteristics.