Primary Hematopoietic and Lymphoid Tissue ›› Bone Marrow ›› Myeloid ›› Erythroid (RBCs & Precursors) ›› Abnormal
Megaloblastoid Nucleated RBC
›Microscopic Features:
- Abnormally Large in size for the stage of maturation (i.e. megaloblastoid)
- Nucleus is round and may be less mature for stage of maturation
›Normal % blood-PB, marrow-BM, lymphoid tissue-LN:
- PB: None
- BM: None
- LN: None
›May Resemble:
›Differential Diagnoses:
B12 or Folate deficiency
Myelodysplastic syndrome
Acute Myeloid Leukemia
Chemotherapy-induced (e.g.Methotrexate)
Myelodysplastic syndrome
Acute Myeloid Leukemia
Chemotherapy-induced (e.g.Methotrexate)
›Classic Immunophenotype:
- CD45-
- CD117-
- CD235a (Glycophorin A) dim+
- CD71+
- Note: The immunoprofile can be variable and may show aberrancies
›Cartoon Image:
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for direct comparison
for direct comparison
›Misc:
Megaloblastoid changes are also commonly noted in non-neoplastic disorders as well (e.g. B12 or Folate deficiency). Hence, interpretation of such findings should be done with extreme caution and always be interpreted in the correct context.