Hemiagenesis of unilateral lobe of thyroid gland

Abstract

The thyroid gland begins its development during the 3rd week of gestation from the median endodermal thickening in the floor of the pharynx that later form the median diverticulum. During development, the thyroid gland normally descends to its typical location in front of the pharynx. Failure of descent has been suggested as a cause of thyroid hemiagenesis; however, the compensatory growth of the other lobe suggests a lobulation defect rather than a failure of descent. Abnormalities during the development lead to defective organogenesis or descent, complete or partial absence of the gland with or without ectopic thyroid tissue. Thyroid hemiagenesis is a rare congenital abnormality characterized by the absence or failure to develop one lobe of the thyroid gland with or without the absence of the isthmus. Unilateral thyroid agenesis (thyroid hemiagenesis) is a rare disorder with less than 300 cases currently in the world literature. Here, we report a case of left hemiagenesis of thyroid.