Modified approach for lingual thyroid transposition: report of two cases.

Lingual thyroid is a rare congenital anomaly of thyroid development resulting from failure of the thyroglossal duct to migrate from the foramen cecum to the prelaryngeal site. The lingual thyroid associated with a fetal adenoma is even more unusual. We presented two cases of lingual thyroid, one associated with fetal adenoma. The ectopic gland was transposed into the muscle space at the floor of the mouth using an extraoral midline lower lip, mandible and tongue-splitting approach in case 1, and a transoral lower lip degloving and midline mandibulotomy and tongue-splitting approach in case 2. Sixteen-year follow-up of case 1 and 6-month follow-up of case 2 showed that the transposed thyroids achieved normal function. Case 2 had no visible scar in the lower lip and mental area. Surgical transposition of the lingual thyroid to the floor of the mouth with the vascular supply intact offers a promising approach for the treatment of this anomaly. The transoral lower lip degloving and midline-splitting approach is recommended because of its better cosmetic outcome.