Type B Lactic Acidosis: A Very Rare but Fatal Complication of Gastrointestinal Solid Tumor.

Type B lactic acidosis, secondary to solid cancer, is very rare. It is mostly seen in patients with hematological malignancies. Although its exact pathogenesis is unknown, it is believed to be caused by overproduction and the inability of tumor cells to remove lactate. In the last 26 years, a systematic review of the literature only identified two previous reports of colorectal cancer-related type B lactic acidosis. Here, we report the third case of severe type B lactic acidosis due to stage IV colorectal with liver metastasis. Besides, this case is unique in that serum lactate levels reaching as high as 24 mmol/L were not reported in association with colorectal cancer. In most cases, the prognosis is still very poor because there are no standardized treatment recommendations. Early chemotherapy is still the only intervention that provides some survival benefits.