Unusual appearance of lingual thyroid in congenital hypothyroidism

The differential diagnosis of congenital hypothyroidism includes an absent gland (athyrosis), an ectopic gland (usually lingual), or an inborn error of metabolism (dyshormonogenesis causing goiter). Thyroid scintigraphy can readily distinguish between these etiologies. Abnormalities in thyroid embryonic development and descent can result in midline thyroid tissue located from the base of the tongue to the mediastinum. Multiple ectopic sites of aberrant thyroid migration are rare, however; most ectopic rests appear as a solitary focus. Ectopic lingual thyroid tissue, although usually asymptomatic and uncomplicated, can cause local obstruction (e.g., dysphasia) or hemorrhage (e.g., hemoptysis).