Endocrine Abstracts

Introduction: During embryogenesis the descent of the thyroid may not proceed normally and may stop at various sites from the base of the tongue to any site of the thyroglossal duct.

Ectopic thyroid tissue, defined as thyroid tissue not located at its normal site (anterolaterally to the second and fourth tracheal cartilages) is rare. Most often, ectopic tissue is located in the base of the tongue.

Case report: We report a 75-year old female referred to our Department for subclinical hyperthyroidism, diagnosed during investigation of atrial fibrillation and weight loss.

She had negative antithyroid autoantibodies, elevated ESR and normal full blood count.

On Tc-99 thyroid scan there was no uptake. Ultrasound showed an enlarged gland with two nodules 1.6 and 1.2 cm on the right and left lobe respectively. Subacute thyroiditis was diagnosed and no special treatment was administered.

Four months later she came back in a worse clinical condition and clinical hyperthyroidism. Considering the possible diagnosis of an ectopic thyroid gland, a whole body scan with Tc99 was performed. It showed hyperfunctioning thyroid tissue in the base of the tongue, with simultaneous suppression of the eutopic thyroid.

She was prescribed antithyroid drugs.

Macroscopic physical examination of the oral cavity was negative, as well as the MRI of the area.

Conclusion: To our knowledge, it is the first case of hyperfunctioning lingual thyroid with simultaneous existence of the eutopic thyroid gland.

Additionally, in reported cases so far ectopic thyroid tissue is usually diagnosed in childhood or adolescence and is usually accompanied by hypo- and not hyperthyroidism.

In most cases, lingual thyroid is visible as a mass in the base of the tongue, in contrast to our case, where it was invisible.

Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.

Funding: This research did not receive any specific grant from any funding agency in the public, commercial or not-for-profit sector.