Thyroglossal duct cyst arises from the remnants of the thyroglossal duct produced by the descent of the thyroid anlage. It usually occurs between the cecal foramen of the tongue and the thyroid gland and rarely arises in the oral floor. We describe our experience with a case of thyroglossal duct cyst of the oral floor. A 50-year-old woman was referred to our hospital because of swelling of the oral floor with dyspnea and mogiarthria. An elastic soft mass, 4 mm in diameter, was palpable. Computed tomographic and magnetic resonance imaging examinations revealed a cystic structure extending from the deep part of the tongue to the oral floor. The cyst was successfully enucleated via an intraoral approach. The pathological diagnosis was a thyroglossal duct cyst. There has been no evidence of recurrence as of 3 years after surgery.
