A Rare Case of Lingual Thyroid with Hypothyroidism

Lingual thyroid gland is a rare clinical entity and occurs due to the failure of the thyroid gland to descend to its normal cervical location during embryogenesis. This ectopic thyroid gland located at the base of the tongue may present with symptoms like dysphagia, dysphonia, upper airway obstruction or haemorrhage and maybe associated with thyroid dysfunction. We are presenting here the case of a 16 year-old girl who reported to our hospital with complaints of foreign body sensation in the throat& dysphagia. The CT scan reported an SOL base of tongue. An emergency surgery was conducted due to sudden appearance of dyspnoea& increase in dysphagia. A post operative Thyroid scan& Biopsy confirmed the diagnosis of Lingual thyroid. Thyroid functions showed Hypothyroidism. The TSH level was 98.1 IU/ml and T3& T4 levels were 0.1 ng/ml& 2.3 g/dl respectively. CONCLUSION Ectopic Thyroid is a rare anomaly with Lingual thyroid accounting for majority of cases. Dysphagia and dysphonia are common presenting symptoms and majority of cases with thyroid dysfunction have hypothyroidism. Pathogenesis of this ectopic is unknown. Genetic factors have been associated with thyroid gland morphogenesis& differentiation but so far no mutation in known genes has been associated with human thyroid ectopy.