The marrow in
megaloblastic anemia may show prominent erythroid hyperplasia with
variable degrees of granulocytic dysplasia, which may resemble
acute leukemia or myelodysplastic syndrome. Clinic history and
additional laboratory studies may be required to look for evidence
of nutritional deficiency.
This case show macrocytic anemia
megaloblastic erythroid hyperplasia in the marrow with frequent
giant bands. Megaloblastic red cells exhibit dramatic maturation
differences between the nucleus and cytoplasm.
have to be differentiated from megaloblastiod changes. The nuclear
chromatin is more delicate and less dysplastic than that in
megaloblastiod changes. Megaloblastoid red cells show more
prominent dyssynchrony, more clumped chromatin, and much coarser
chromatin strands. The clear spaces between the dense chromatin
strands (euchromatin) are more prominent in megaloblastoid
nuclei. Besides showing abnormal maturation compared to the
cytoplasm, megaloblastoid red cells may exhibit more ominous and
distinctly neoplastic morphology; the nucleus may be enlarged,
grotesquely shaped, lobulated, fragmented, or multinucleated. The
cytoplasm may be vacuolated and contain multiple Howell-Jolly
bodies or exhibit coarse basophilic stippling. If the red cell is
severely dysplastic, a PAS stain may show clumped cytoplasmic
positivity. Megaloblastoid and dysplastic nucleated red cells are
found in many different conditions, including DiGuglielmo’s
syndrome, acute leukemias, myelodysplasia, myeloproliferative
neoplasm, and congenital dyserythropoietic anemias.
Megaloblastoid change and lesser degrees of dysplasia may also
develop after exposure to certain toxins, antibiotics, and
antimetabolites, and with excess alcohol consumption.