BLACK CARTILAGE AFTER THERAPY WITH LEVODOPA AND METHYLDOPA

A study was undertaken of 14 autopsy cases with pigmented rib cartilag e. Twelve of these patients had been treated with levodopa because of Parkinson's disease for at least 6 years, and two had been treated wit h methyldopa because of essential hypertension for 19 years. Thirty-tw o percent of the autopsy cases of Parkinson's disease during a recent 70-month period demonstrated pigmented rib cartilage. Only one of them also demonstrated pigmentation of intervertebral disks. No abnormal p igmentation was seen in other sites. The pigment was located in the hy aline matrix of rib cartilage and in necrotic chondrocytes. Levodopa w as chromatographically demonstrated within the cartilage of patients w ith Parkinson's disease, but in both pigmented and unpigmented sites. It is speculated that a pigmented drug metabolite is bound preferentia lly to the matrix of rib cartilage. Dopa pigmentation only occurs in c artilage and differs in several respects from endogenous and exogenous ochronosis. It appears to be harmless but irreversible.