| Red blood cell, shape abnormality | Acanthocyte |
| Also known as | Spur cells from the Greek acantha “thorn“ (some have advocated restricting the term acanthocyte for those with hereditary neurological syndromes, and spur cell for the remainder of cases). |
| Definition | Acanthocytes are densely stained, spheroidal red blood cells that lack central pallor and have 3-20 irregularly distributed, thorn-like projections of variable size/length/thickness, often with drumstick (knobby) ends. Spicules may occasionally have branches. |
| Ddx | Must be differentiated from burr cells. Small contracted cells in pyruvate kinase have the appearance of acanthocytes but they do not carry that name. |
| Conditions associated with the shape abnormality | Hereditary abetalipoproteinemia (hereditary acanthocytosis), McLeod syndrome/phenotype and chorea-acanthocytosis; severe end-stage liver disease, post splenectomy, hypothyroidism, anorexia nervosa, and chronic starvation. |
| Mechanism of formation | Membrane defect associated with increased RBC cholesterol with reduction in other major phospholipids and decreased cholesterol: PL ratio. Imbalance in cholesterol and PL leads to preferential expansion of the outer leaflet of lipid bilayer. Mechanism probably differs in abetalipoproteinemia, where lack of a structural protein plays a role. |
| History | First described in 1950 by Bassen and Kornzweig; named in 1952 by K. Singer. Spur cell anemia first reported in 1964. |
| Source/author | William Aird |
| Reviewed and edited by | Parul Bhargava |
