Type B lactic acidosis and metastatic breast cancer.

A case is presented of a patient with longstanding metastatic breast cancer whose condition suddenly deteriorated due to hypercalcemia and severe lactic acidosis which rapidly proved fatal. Postmortem examination showed no explanation for the lactic acidosis other than extensive metastatic disease. A review of the rare syndrome of malignancy-induced lactic acidosis is presented with particular emphasis on the 5 other cases reported in association with metastatic breast cancer. Theories of pathogenesis and management controversies are discussed.