Submental thyroid ectopy might cause subclinical hypothyroidism in early childhood

OBJECTIVE: Thyroid ectopy is a rare condition resulting from abnormal embryologic development and migration of the gland. Sublingual is the most common thyroid ectopy; all other ectopic thyroid locations occur very rare. There are no reports in the literature that describe the clinical course of patients with congenital hypothyroidism due to thyroid ectopy. METHODS AND RESULTS: We present a child with congenital hypothyroidism detected on neonatal screening which had a subclinical course during follow-up. Scintigraphy revealed submental thyroid ectopy, a rare ectopic location and no orthotopic thyroid gland. CONCLUSION: Our case is unique because of the rare ectopic thyroid location but also of the unexpected clinical course; however, further thyroid monitoring is required for the therapy adjustment and detection of any changes in the ectopic tissue.