B-cell lymphoma, thiamine deficiency, and lactic acidosis.

Type B lactic acidosis is found in the absence of tissue hypoperfusion, can be associated with malignancies, and can be caused by thiamine deficiency. We present a patient who presented with an abdominal mass that biopsy disclosed to be a diffuse large B-cell lymphoma. Because thiamine deficiency is a rare cause of lactic acidosis in cancer, the patient was treated with intravenous thiamine with rapid normalization of the lactic acid level. The level prior to treatment was low. The case emphasizes a rare cause of lactic acidosis.