Multiple myeloma associated with lactic acidosis.

Type B lactic acidosis is rare among patients with malignant diseases. To date only one case report has documented lactic acidosis occurring in a patient with multiple myeloma (MM). Our patient, a 55-year-old black man, was diagnosed with stage IIIA immunoglobulin G-kappa (IgG-kappa) MM in September 1995. He was found to have severe lactic acidosis at the time of second relapse. During the terminal phase of his disease, he required multiple hospitalizations for management of lactic acidosis and other complications of his MM. No other cause of his elevated lactate levels was identified. Although type B lactic acidosis may more commonly occur in patients with leukemia or lymphoma, it may rarely present in patients with rapidly progressive and refractory MM.