Retinoid-induced hypercalcemia in a patient with Kaposi sarcoma associated with acquired immunodeficiency syndrome

Retinoids are commonly used for the treatment of nonmalignant skin disorders and occasionally for the treatment of various neoplasms including epidemic Kaposi sarcoma (KS). Dry skin and mucus membranes, muscle and joint aches, alopecia, headaches, and liver and lipid abnormalities are the most frequent medication-related side effects. Very rarely, this class of drugs is associated with the development of hypercalcemia. The authors report the case of a man with acquired immunodeficiency syndrome (AIDS)-associated KS who, while participating in a phase II clinical trial of LGD 1057 (9-cis-retinoic acid) for treatment of epidemic KS, developed hypercalcemia, mental status changes, and renal insufficiency. The etiologic factors of retinoid-induced hypercalcemia are imperfectly understood, but with drug withdrawal his serum calcium, mental acuity, and renal function quickly normalized. Hypercalcemia occurs infrequently in the setting of AIDS and when present, is usually mediated by opportunistic infections. Clinicians should be alert to this potentially life-threatening iatrogenic complication that responds favorably to drug withdrawal.