Follicular carcinoma arising in a large ectopic lingual thyroid: a case report and review of literature

Ectopic lingual thyroid has been described, however, follicular carcinoma arising within it is an extremely rare entity with only 40 cases reported in the literature. Lingual thyroid carcinoma is undistinguishable from benign enlargement of lingual thyroid, the later should also be differentiated from many oropharyngeal pathologies including but not limited to thyroglossal duct cyst, lipoma, dermoid cyst and salivary gland tumors. Ectopic lingual nature of thyroid tissue can be diagnosed with scintigraphy scan; however, malignant transformation confirms just after pathological examination. Surgical excision remains the best therapy with transoral approach being the most appropriate and favorable among others due to its cosmetic results and lower incidence of infection. Herein, we report a case of an adult female who was diagnosed to have follicular carcinoma of an ectopic lingual thyroid tissue mass. Concerning the size of the mass it was the largest of all reported cases of ectopic thyroid gland.