Acanthocyte (from the Greek word ἄκανθα acantha, meaning 'thorn'), in biology and medicine, refers to a form of red blood cell that has a spiked cell membrane, due to abnormal thorny projections. A similar term is spur cells. Often they may be confused with echinocytes or .
Acanthocytes have coarse, weirdly spaced, variably sized crenations, resembling many-pointed stars. They are seen on blood films in, among others abetalipoproteinemia,liver disease, chorea acanthocytosis, McLeod syndrome, and several inherited neurological and other disorders, such as neuroacanthocytosis,anorexia nervosa, infantile pyknocytosis, hypothyroidism, idiopathic neonatal hepatitis, alcoholism, congestive splenomegaly, Zieve syndrome, and chronic granulomatous disease.
Spur cells may refer synonymously to acanthocytes, or may refer in some sources to a specific subset of 'extreme acanthocytes' that have undergone splenic modification whereby additional cell membrane loss has blunted the spicules and the cells have become spherocytic ('spheroacanthocyte'), as seen in some patients with severe liver disease.
Acanthocytosis can refer generally to the presence of this type of crenated red blood cell, such as may be found in severe cirrhosis or pancreatitis, but can refer specifically to abetalipoproteinemia, a clinical condition with acanthocytic red blood cells, neurologic problems and steatorrhea. This particular cause of acanthocytosis (also known as abetalipoproteinemia, apolipoprotein B deficiency, and Bassen-Kornzweig syndrome) is a rare, genetically inherited, autosomal recessive condition due to the inability to fully digest dietary fats in the intestines as a result of various mutations of the microsomal triglyceride transfer protein (MTTP) gene.