Clinical Characteristics of Ectopic Thyroid in Korea

BACKGROUND: Ectopic thyroid is a rare entity and can occur at any location in the midline position. A role for the ectopic thyroid in the pathogenesis of hypothyroidism and nongoitrous cretinism has been emphasized. OBJECTIVE: To assess the clinical characteristics of an ectopic thyroid by analyzing 49 cases reported in Korea. DESIGN: This study was a retrospective review of 19 cases who were diagnosed by thyroid scan at our institutions together with 30 cases reported in the Korean medical literature, found using KoreaMed. MAIN OUTCOMES: Most cases of ectopic thyroid were diagnosed in patients aged between 1 and 29 years; it was more common in females (43 patients). A lingual thyroid was found in 23 patients, a sublingual thyroid in 17 patients, combined type in 7 patients, a prelaryngeal thyroid in 1 patient, and an intratracheal thyroid in 1 patient. Only four cases had the thyroid gland in the normal position. The chief complaints at presentation were palpable mass in 20 patients, growth retardation in 10 patients, and a lump sensation in the throat in 6 patients. Twenty-six of 42 patients (61.9%) had hypothyroidism, and 16 patients (38.1%) had euthyroidism. As for the treatment modalities, 18 of 26 patients with hypothyroidism and 4 of 16 patients with normal thyroid function received thyroid hormone medication; 3 of 26 patients with hypothyroidism and 8 of 16 patients with euthyroidism underwent resection of the ectopic thyroid. CONCLUSION: Our study suggests that radionuclide thyroid scanning and function testing may be useful not only for the diagnosis of an ectopic thyroid but also before deciding on the therapeutic modality; patients should be followed up to detect changes in thyroid function and malignant transformation.