Dual ectopic thyroid: case series and review of the literature.

Ectopic thyroid tissue is an uncommon congenital aberration. It is further unusual for ectopic thyroid to be present at 2 different sites simultaneously. Only 19 cases of dual ectopic thyroid have been reported in the English literature. Most of the patients were adolescents and presented with anterior neck swelling with or without altered metabolic status. Lingual/sublingual thyroid was the most common ectopic location. Subhyoid was the most common site of a second ectopic thyroid in these patients. The thyroid scan has been used successfully to diagnose ectopic thyroid tissue. We report 4 such cases in which ectopic thyroid tissue was simultaneously present at 2 different locations using thyroid scanning. The literature of already reported cases is reviewed in detail.