Increased Eosinophilic Precursors in Megaloblastic Bone Marrow — An Interesting Observation

Megaloblastic maturation of erythroid precursors is seen in cases of vitamin B12 and folic acid deficiency and needs a thorough evaluation. In the present study we have evaluated 342 bone marrow aspiration smears by doing a thorough differential count and findings were recorded. In addition to giant metamyelocytes we have observed that eosinophilic precursors were significantly increased in 78% of the cases. Interestingly, none of them had eosinophilia in peripheral blood. Such finding was not reported in megaloblastic marrow till date to the best of our knowledge. All the patients had deficiency of cobalamine and folic acid either both or one of them with a characteristic megaloblastic maturation of the erythroid precursors. The reason for such finding can be hypothesized to be a result of various interleukins (IL-5, IL-3) and growth factors that play a major role in hemopoietic cell maturation. The awareness of this finding of eosinophilic precursors in increased percentages in a megalobalstic marrow is important because megaloblasts are also found in marrows with increased eosinophils like chronic eosinophilic leukemia and hypereosinophilic syndrome but they have peripheral eosinophilia in addition, which is absent in megaloblastic anemia.