[Hypothyroidism and acanthocytes: diagnostic significance of blood smear]

We report on 3 cases of hypothyroidism in which the diagnoses were suspected after having observed acanthocytes on the blood film. The diagnostic value of this erythrocyte change has been neglected, although the results of studies have shown a test specificity of 87-99%, other diseases related to acanthocytes being very rare. After an analysis of the studies and case reports dealing with acanthocytes we conclude that hypothyroidism must be excluded in all cases where acanthocytes are observed on the blood film.