Dual thyroid ectopia.

Ectopic thyroid gland is a rare embryological fault of thyroid development. Dual ectopic thyroid is even more rare and only 8 cases have been reported in the literature. The author presents a case of dual ectopic thyroid in a 16-year-old boy with an anterior neck mass, which is gradually growing in size particularly in the last 2 years. The initial diagnosis was thyroglossal duct cyst. Thyroid function test revealed elevated thyroid-stimulating hormone. Ultrasound of the neck did not show thyroid gland in its normal pretracheal position. Thyroid scan (Technetium 99) revealed the diagnosis of dual thyroid ectopia (lingual and subhyoid).