Xanthoma disseminatum associated with inflammatory arthritis and synovitis--a rare association.

Xanthoma disseminatum (XD) is a rare, benign, non-Langerhans cell histiocytosis characterized by disseminated xanthomatous lesions with a predilection for the face, flexures, and mucosae. Approximately 100 cases have been reported in the literature. We report XD in an 8-year-old boy with symmetric synovitis and arthritis involving the wrists and knees. This case is interesting in view of the association between arthritis and synovitis and XD, which to our knowledge has not been reported in the literature. This case has to be differentiated from multicentric histiocytosis, another non-Langerhans cell histiocytosis, in which joint involvement is common.