In hereditary spherocytosis, which morphological finding is most characteristic on peripheral smear?

• A. Spherocytes
• B. Target cells
• C. Acanthocytes
• D. Elliptocytes

Answer: (A)

The key idea is that hereditary spherocytosis is defined by a membrane skeleton defect in red blood cells, which causes a loss of membrane surface area without a proportional loss of hemoglobin. This makes the cells become round and small, losing their central pallor, so the peripheral smear shows numerous spherocytes. These sphere-shaped cells are less deformable and get sequestered in the spleen, leading to hemolysis and a compensatory rise in reticulocytes and sometimes increased MCHC. While other morphologies like target cells, acanthocytes, or elliptocytes can appear in various other disorders (target cells with liver disease or thalassemia; acanthocytes with lipid disorders; elliptocytes with hereditary elliptocytosis), the presence of spherocytes is the most characteristic finding for hereditary spherocytosis.