The benign long-term effect of cholesterol crystal synovial cysts.

Synovial effusions containing cholesterol crystals are uncommon. Most of the few reported cases have been found in patients with seropositive rheumatoid arthritis. In vitro studies, as well as an animal model, have suggested that cholesterol crystals could have a role in inflammation of the joints. In this report we present a case of seronegative arthritis, complicated by large carpal synovial cysts which contained numerous cholesterol crystals. The long-term presence of the cysts, without evidence of joint destruction, suggests that cholesterol crystal formation is probably a rare epiphenomenon, rather than a harbinger of inflammation.