Submental Ectopic Thyroid in a Patient with an Orthotopic Thyroid Gland.

Ectopic thyroid is a rare clinical disease, with the majority of the patient presented with hypo-functional thyroid tissue and absence of orthotopic thyroid gland. During embryogenesis, the thyroid gland descends from the foramen cecum to its normal position located below the larynx and hyoid bone, anterior to the 2nd, 3rd, and 4th tracheal cartilaginous rings. Any defect that occurs during this period will result in ectopic thyroid. Hence, ectopic thyroid is usually found along the course of the thyroglossal duct, laterally in submandibular glands and even in distant places such as mediastinum or very rarely in sub-diaphragmatic organs. However, the presence of an orthotoptic thyroid may lead some difficulties in the diagnosis of this disease; hence, fine-needle aspiration is recommended to avoid unnecessary operation provided the patient is asymptomatic.