Lingual thyroid and hypothyroidism. Report of a case in a middle aged woman.

There are approximately 400 reported cases of lingual thyroid (LT) with a clear cut prevalence in paediatric age. These glands are probably quantitatively deficient and function at marginal levels. Thyro-stimulating hormone (TSH) causes hypertrophy producing local symptoms and in younger patients may induce dangerous obstruction. The presumptive diagnosis is usually made by indirect laryngoscopy and thyroscintigraphy. The authors describe a case of LT in a middle aged patient in whom the anomaly remained undiscovered, being without local symptoms, and permitting a normal life. The discovery was made possible by the development in the last four years of a progressive, frank hypothyroidism, probably induced by silent thyroiditis into the ectopic gland.