Lingual thyroid presenting after previous thyroglossal cyst excision.

Lingual thyroid is a rare lesion caused by maldescent of the thyroid gland. It is an important cause of a mass on the posterior third of the tongue, and may coexist with other developmental abnormalities such as thyroglossal cyst. The diagnosis is made by radioisotope scan. Treatment is indicated in the presence of symptoms and consists initially of thyroxine. Severe or unresponsive cases require complete excision through a lateral pharyngotomy. Hypothyroidism is common postoperatively, but may be avoided in some cases by transplantation of excised tissue. We present a case report and review of the literature.