Abstract

In pediatric patients, ectopic thyroid, a form of congenital hypothyroidism, is commonly detected during neonatal mass screening. A variety of clinical manifestations of ectopic thyroid have been reported. We present herein a patient with dual ectopic thyroid showing an atypical clinical course, who was observed over a long-term follow-up period. The patient, an 8-year-old female, received the diagnosis of ectopic thyroid after a mass in her anterior neck was analyzed. Initially, her thyroid function was normal. Imaging data revealed an ectopic thyroid at the lingual root and on the thyroid cartilage. The patient showed late-onset hypothyroidism. The mass gradually enlarged (to 3 cm in length and 4 cm in width) until age 25 year when the patient’s TSH level increased. The peak TSH level at the TRH test was 40.1 μU/ml. Thyroid hormone replacement therapy was started. Ectopic thyroid should be carefully followed-up even when asymptomatic because the clinical course may be late-onset, especially in patients with dual ectopic thyroid.