Colloid cyst in ectopic thyroid gland.

A five year old girl presented with a mid-line neck swelling. At operation, a multiloculated cyst was excised with a portion of hyoid bone and a suprahyoid gelatinous tract extending into the base of the tongue. Histology revealed a benign colloid cyst with associated thyroid tissue. Post-operative investigations indicated severe hypothyroidism. The cystic nature of the lesion was misleading at operation and pre-operative thyroid ultrasonography (US) is recommended for all patients with suspected thyroglossal tract cysts (TGC).