Unusual morphologic abnormalities of megaloblasts in pernicious anemia and folate deficiency.

Three types of morphologic abnormalities of megaloblasts in the bone marrows of eight patients with severe untreated pernicious anemia and two patients with folate deficiency are described. A fourth type of abnormality, probably indicating disturbances in hemoglobin synthesis, was also observed in megaloblasts from patients with these conditons. In addition to the phenomenon of erythrophagocytosis in these disorders, the degenerating megaloblasts and those showing disturbances of hemoglobinization may constitute additional cytologic evidence for intramedullary destruction of erythroid precursors contributing to ineffective erythropoiesis in these disorders.