Bone marrow aspirate from a 62-year-old man with refractory anemia shows erythroid hyperplasia. Prussian blue staining reveals numerous erythroblasts with a perinuclear ring of blue granules. The granules represent iron deposited in which intracellular location?

• A Lysosomes of macrophages
• B Nucleus of normoblasts
• C Mitochondria of erythroid precursors ✓
• D Cytoplasmic ferritin aggregates of plasma cells

Explanation

Sideroblastic anemia results from defective heme synthesis within the erythroid precursor. Iron that cannot be incorporated into protoporphyrin accumulates in the mitochondria, which cluster around the nucleus of the erythroblast, producing the pathognomonic ringed sideroblast on Prussian blue staining. Iron loaded lysosomes are hemosiderin in macrophages and reflect storage iron rather than a synthetic block, and the nucleus itself never stores iron.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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