Abstract
INTRODUCTION AND IMPORTANCE: Having two or more sites of simultaneous ectopic thyroid tissue is a rare phenomenon. Thyroid ectopia should be considered in congenital hypothyroidism where no eutopic thyroid gland is found. CASE PRESENTATION: This case describes an incidental finding of dual ectopic thyroid tissue on computer tomography scan in an adult with known congenital hypothyroidism that was previously attributed to thyroid agenesis. The decision was made to proceed with a Sistrunk procedure to excise the ectopic submental thyroid as it became more noticeable after weight loss following bariatric surgery, and to monitor the remaining lingual thyroid with a combination of clinical symptomology, imaging and thyroid function studies given its challenging location. CLINICAL DISCUSSION: The literature on pathophysiology, imaging modalities, and common considerations for surgical extirpation is reviewed. CONCLUSION: The utility of thyroid scintigraphy may be limited in patients with known thyroid ectopia; other investigative modalities are helpful. The Sistrunk procedure was used to excise an ectopic thyroid, based on its embryological migration from the foramen caecum to the usual pretracheal position along the thyroglossal tract, and is a suitable technique for excision of submental thyroid tissue causing an unsightly mass and where thorough histopathological examination is required to exclude malignancy.