[Therapy-resistant microcytic hypochromic anemia from malabsorption-related vitamin B6 deficiency after a gastrointestinal operation].

We present a case of a 33-year-old man, who had a past history of a total pancreatectomy for duodenal malignant lymphoma complicated by life-threatening bleeding during chemotherapy at 23 years of age. He achieved complete remission and received no more chemotherapy. Around August 1999 he developed anemia, which failed to improve following intravenous administration of iron, and he was hospitalized. The cause of the anemia remained unclear and he received a blood transfusion. Because of the increasing frequency of transfusions, he was admitted to our hospital to evaluate his anemia in September 2000. On examinations, laboratory findings revealed a low level of serum vitamin B6 (B6) with iron deficiency. Intravenous administration of B6 was performed in addition to iron, with the result that the patient's hemoglobin level was kept at 10 g/dl without blood transfusion. An oral B6 administration test resulted in a low level of B6. These results suggest that B6 deficiency due to malabsorption may cause therapy-resistant anemia. Some reports say that B6 deficiency causes microcytic hypochromic anemia, since B6 is necessary for erythrocytic hemopoiesis as a coenzyme for heme biosynthesis. In the case of microcytic hypochromic anemia, if the cause is unclear, evaluation should be performed, taking the possibility of a hidden cause of B6 deficiency into consideration.