PERIPHERAL SMEAR AND BONE MARROW FINDINGS IN MEGALOBLASTIC ANEMIA

PERIPHERAL SMEAR AND BONE MARROW FINDINGS IN MEGALOBLASTIC ANEMIA

PERIPHERAL SMEAR FINDINGS

• Red Blood cells

  • RBC’s are characteristically large and oval (Macrocytosis)

  • In severe anemia along with macroovalocytes other variations in RBC’s are

    • Marked anisopoikilopoiesis ( variation in size and shape of red cells)

    • Basophilic stippiling

    •  Howell-jolly bodies

    • Cabot tings

  • Late or intermediate erythroblasts may some times be seen in severe anemia

• White blood cells

  • Total leukocyte count – may be normal or decreased

  • Leukopenia is more marked in severe anemia

  • Hypersegmentation of neutrophil nuclei is one of the earliest sign

• Platelets

  • Thrombocytopenia is usual

  • Giant platelets can be some times seen

BONE MARROW FINDINGS

• Marrow is hypercellular with megaloblastic features in all erythroid precursors

• Erythroid precursors

  • Megaloblasts differ from normablasts in having increase in cell size,  nuclear size and amount of cytoplasm. Nuclear chromatin is sieve like or stippled. Nuclear maturation falls behind the cytoplasmic maturation (Nuclear – cytoplasmic asynchrony)

  • Depending upon the stage they are termed as promegaloblast, early, intermediate and late megaloblasts

  • In bone marrow early erythroid precursors with megaloblastic features are increased (promegaloblasts and early megaloblasts) when compared to more mature precursors (intermediate and late megaloblasts)

  • Mitotic activity is increased

• Myeloid series

  • Granulocytic series also show megaloblastic features.

  • Giant metamyelocytes and band forms with horse shoe shaped nuclei and finer chromatin is the characteristic feature

• Megakaryocytes are large with multiple nuclear lobes and paucity of cytoplasmic granules

Reference

• Shirish M Kawthalkar. Essentials of Hematology. First edition. 2006