Lingual Thyroid: 35-Year Experience at a Tertiary Care Referral Center

Barbara G. Carranza Leon, MD; Adina Turcu, MD; Rebecca Bahn, MD; Diana S. Dean, MD

Disclosures

Endocr Pract. 2016;22(3):343-349. 

In This Article

Abstract and Introduction

Abstract

Objective: Lingual thyroid (LT) results from a developmental abnormality due to failure of the thyroid gland to descend to its pretracheal position. Given the low incidence of this disease, standardized management recommendations are lacking. We aimed to describe our institution's experience in LT management and to suggest a practice algorithm.

Methods: We conducted a retrospective review of LT diagnosed at Mayo Clinic, Rochester, Minnesota, between1976 and 2010. Demographics, clinical presentation, laboratory data, treatment received, and outcomes were collected.

Results: We identified 29 patients with LT. Eighty-three percent were female; age at diagnosis ranged from 2 weeks to 68 years. Almost one-third of patients were symptomatic, with the most common symptoms being cough and hoarseness. The diagnosis of LT was incidental in 9 patients (31%). Seventy-two percent of patients developed hypothyroidism. Levothyroxine was the treatment of choice, followed by thyroidectomy. Two asymptomatic euthyroid patients were followed without any intervention.

Conclusion: Management of patients with LT should be individualized and guided by the patient's symptoms and thyroid hormone status.

Introduction

Lingual thyroid (LT) is a rare embryologic anomaly that refers to an ectopic thyroid gland located at the base of the tongue. While thyroglossal duct cysts usually contain ectopic rests of thyroid tissue and represent the most common congenital masses of the midline neck, the base of the tongue is the most frequent ectopic site for an intact thyroid gland.[1,2] LT results from the failure of the thyroid gland to descend from the foramen caecum to its normal prelaryngeal location. As a result, the thyroid tissue remains at the base of the tongue and is usually situated in the midline. In 70% of LT cases, the orthotopic thyroid tissue is absent.[3] The incidence of LT has been reported to be between 1 in 300 and 1 in 100,000 population, with a female predominance.[4,5] In 1976, screening for congenital hypothyroidism was incorporated to the newborn screening program,[6] and 25 to 42% of cases of congenital hypothyroidism were found to have a LT.[7,8] Most cases of LT are identified during newborn screening, but close to 1.6% of LT cases are missed.[8] Many patients without congenital hypothyroidism remain asymptomatic throughout life, while others may present with local symptoms such as discomfort, voice changes, dysphagia, or orthopnea. Some cases are discovered incidentally on physical exam or imaging studies. While most patients are hypothyroid or euthyroid, rare cases of hyperthyroidism have been reported.[9] Carcinoma arising in a LT is rare, with an estimated incidence of 1%.[10]

Treatment options for LT include thyroid hormone suppression therapy, radioactive iodine (RAI), and surgical excision. However, a consensus in management has not yet been formulated. Herein, we report our institution's experience with LT over 3 decades and suggest an approach to management.

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