A rare combination of acute myeloid leukemia with Vit B12 deficiency: Case report

•The incidence of macrocytic anemia and leukemia in one patient is infrequent.•The theory of somatic mutation could explain the development of leukemia in patients with macrocytic anemia.•Pure chance is the most acceptable theory in the light of the low incidence of the Combination.•Vitamin B12 and folic acid could correct the abnormal response of granulocytic.•The vitamin B12 treatment Support leukemia.