Giant Metamyelocyte

An atypical myeloid cell with clumped chromatin in a large, often bizarre, immature nucleus, and relatively mature cytoplasm. Giant metamyelocytes are typical of megaloblastic anemia (due to a vitamin B12 and/or folic acid deficiency), as nuclei cannot properly mature without single-carbon transport which is largely dependent on vitamin B12 and folic acid
References in periodicals archive ?
BM Aspirate from a patient with Megaloblastic Anaemia showing Megaloblastic Erythropoiesis and a Giant Metamyelocyte. Leishman Stain x40
[1] Giant metamyelocyte and stab forms were noted in 10 cases of megaloblastic anaemia.
33) patients had dysmyelopoeisis which included abnormal shaped nuclei, folded, cleaved nuclei, giant metamyelocyte, myelocyte, pseudo pelger heut anomaly, vacuolisation of the cells and maturation arrest.
In Visceral leishmaniasis marrow shows several changes which includes presence of LD bodies decreased myeloid-erythroid ratio indicating relative suppression of myelopoiesis, increased number of plasma cells, presence of giant metamyelocytes indicating suppression of cell division, presence of juvenile megakaryocytes signifying increased formation of platelets to meet demand caused by increased destruction in hyperactive spleen, presence of micronormoblasts in aggregates indicating splenic hyperactivity and crenated LD bodies with deformed cell membranes in cases of treated kala-azar.11 The cases diagnosed with visceral Leishmaniasis in this study depicted some of the changes like plasma cell prominence and increased number of macrophages.
The bone marrow aspiration of megaloblastic anaemia showed numerous megaloblasts with large cells with an increased nuclear/cytoplasmic ratio, sieve-like chromatin and giant metamyelocytes (Figure B).
Myeloid series showed giant band forms and giant metamyelocytes. In microcytic anemia, micronormoblasts were noted.
Giant metamyelocytes and giant band forms were seen in myeloid series.