elliptocytesovalocytes

Elliptocytes and ovalocytes are red blood cells that assume elongated, oval, or pencil-like shapes rather than the normal round, biconcave form. Elliptocytes tend to be slender and elongated, while ovalocytes are distinctly oval with rounded ends. On a peripheral blood smear they appear longer than typical red cells, with variable central pallor.

These cell shapes arise from a variety of causes, most notably congenital membrane disorders. Hereditary elliptocytosis is caused by defects in red cell membrane proteins such as spectrin, ankyrin, or protein 4.1, leading to a spectrum of fragility and hemolysis. More severe forms include hereditary pyropoikilocytosis. Southeast Asian ovalocytosis (SAO) is another well-described hereditary condition, due to mutations in the band 3 (SLC4A1) protein, producing rigid, oval cells and often providing some protection against malaria in endemic regions. Elliptocytes and ovalocytes can also be seen in acquired conditions such as myelodysplastic syndromes, iron deficiency, megaloblastic anemia, or autoimmune hemolytic processes, as well as occasionally as artifacts from blood smear preparation.

Clinical significance varies with the underlying cause. Many individuals with hereditary elliptocytosis or SAO are asymptomatic or have mild hemolysis, while others may experience anemia, jaundice, or splenomegaly. Diagnosis rests on the peripheral smear appearance, supported by family history and, when needed, genetic testing or membrane-protein studies.

Management is typically supportive and directed at the underlying condition, including folate supplementation for ongoing hemolysis and monitoring for complications. Splenectomy is rarely indicated and reserved for select severe cases. The presence of elliptocytes or ovalocytes highlights a red cell membrane disorder and prompts confirmation by genetic or laboratory evaluation.