Acanthocytes have 3-12 thorn-like projections irregularly spaced around the cell. Since these cells have lost their discoid shape, they are frequently smaller than normal and have little or no central pallor. Acanthocytes have an excess of cholesterol and an increased surface area. Large numbers of these cells on a smear can be of diagnostic significance. The largest percentage, 50-100% of circulating red cells, can be seen in the rare abetalipoproteinemia (hereditary acanthocytosis). Acanthocytes are easily seen as horned cells in the smear shown on the right.