Related to deficiency of vitamin B12 or folate or by related processes that lead to impaired DNA synthesis.
Typically the nucleus in erythroblasts have a defective DNA synthesis with delayed maturation.
Discordant maturation is termed megaloblastic.
Nuclear chromatin is basophilic, clumped and has a bizarre appearance with lacy and irregular appearance.
Bone marrow erythropoietin is increased.
Maturation defect can also be observed in myeloid and megakaryocyte lines.
Megakaryocytes and granulocytes have hypersegmentation, and metamyelocytes and bands are abnormally increased in size.
Can lead to leukopoenia nd thrombocytopenia in addition to anemia.
Most common causes of MAs are acquired, although congenital forms exist.
The most common causes relate to deficiencies in cobalamin, folate, or both.
The most common cobalamin deficiency is pernicious anemia.
Less common manifestations of cobalamin deficiency can occur as a result of gastrectomy, terminal ileum inflammatory disorders, and small bowel infestation with fish tapeworm.
Folate deficiency is most commonly associated with inadequate dietary intake.
Rbc’s in MA have abnormal nuclear maturation and nuclear and cytoplasmic maturation imbalance.