megaloblast

an abnormally large form of any of the CELLS that go on to produce ERYTHOCYTES (red blood cells). In certain forms of ANAEMIA (megaloblastic anaemias), they are found in the BONE MARROW , and their presence is the result of a deficiency of VITAMIN B12 or of FOLIC ACID . They indicate a failure in the maturation process of erythrocytes, which results in anaemia.