A case of megaloblastic anemia presented as pancytopenia and increased serum vitamin $B_{12}$ level

Low serum vitamin (cobalamin) level is a valuable indicator of cobalamin-deficiency megaloblastic anemia, which sometimes presents as pancytopenia. It can also be diagnosed by cobalamin deficiency if the patient shows related clinical symptoms and increased serum homocysteine or urine methylmalonic acid, metabolites of cobalamin, although the serum cobalamin level may be normal. We report a case of cobalamin-deficiency megaloblastic anemia presenting as pancytopenia with an increased serum vitamin level.