A 48-year-old man with chronic alcoholism and cirrhosis has hemoglobin 10 g/dL and MCV 104 fL. Peripheral smear shows large oval red cells with marked target cells but no hypersegmented neutrophils. Serum bilirubin is 3 mg/dL and LDL cholesterol is low. This macrocytosis is best explained by:

• A Autoagglutination of red cells falsely raising measured volume
• B Impaired DNA synthesis causing nuclear cytoplasmic dyssynchrony
• C Excess membrane lipid relative to cell volume from abnormal lipoprotein metabolism ✓
• D Reticulocytosis from occult gastrointestinal bleeding

Explanation

Liver disease causes nonmegaloblastic macrocytosis because abnormal plasma lipid composition deposits excess cholesterol and phospholipid into the red cell membrane, enlarging the cell without altering DNA maturation. Hence there are no hypersegmented neutrophils, and target cells appear from redundant membrane. Dyssynchrony defines megaloblastic anemia, agglutination raises MCV spuriously in cold agglutinin disease, and reticulocytes are polychromatophilic larger cells seen after acute blood loss.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.