Which marrow finding is consistent with a responsive anemia?

• A. Erythroid hyperplasia
• B. Myeloid hypoplasia
• C. Erythroid hypoplasia
• D. Myeloid metaplasia

Answer: (A)

When the body detects anemia, the bone marrow ramps up red blood cell production to restore oxygen-carrying capacity. This compensatory increase in erythroid precursors is called erythroid hyperplasia. It reflects an active, appropriate response to anemia, and you may also see evidence of increased erythropoiesis in the peripheral blood as reticulocytosis. Erythroid hypoplasia would mean reduced red cell production, not a compensatory response. Myeloid hypoplasia points to underproduction of white blood cells, not red cells. Myeloid metaplasia indicates abnormal, often extramedullary hematopoiesis, not the straightforward marrow expansion seen with a responsive anemia. So the marrow finding that best fits a responsive anemia is erythroid hyperplasia.