Incidental Finding of Dual Ectopic Thyroid on Computed Tomography Angiography

Abstract

The presence of simultaneous two ectopic foci of thyroid tissue (dual ectopic thyroid) is rare, and few cases have been reported in the literature. The ectopic thyroid tissue is an extremely uncommon embryological aberration due to the alterations occurring during the embryological development with incomplete migration of thyroid precursors. Commonly ectopic thyroid tissue is a midline structures, but the lateral location is possible but very rare. Ectopic thyroid is common in women and can vary in size from a microscopic focus to a few centimeters. The normal process of migration of the thyroid can be interrupted at various levels determining a lingual ectopy, a sublingual ectopic, prelaryngeal ectopy, or mediastinic ectopy. Intrathoracic and subdiaphragmatic organs are other sites where the ectopic thyroid tissue may be present. In most of the cases, ectopic tissue is a lingual thyroid and this condition can be totally asymptomatic, discovered incidentally, or occurs with symptoms such as dysphonia, dysphagia, dyspnea, and hemoptysis. Sublingual or suprahyoid ectopia is rare and even rarer are the cases of two foci of ectopic thyroid tissue simultaneously present. On imaging, the ectopic tissue shows the same characteristics of orthotopic thyroid tissue and similarly can undergo goiterous and cancerous transformation. We report a case of incidental dual ectopic thyroid in lingual and suprahyoid level in a 72-year-old female patient, asymptomatic and with normal thyroid function, who underwent computed tomography (CT) angiography before vascular surgery for the treatment of carotid stenosis. The presence of a lingual thyroid can lead to a difficult and dangerous intubation, with possible fatal consequences. For this reason, the discovery of these abnormalities has totally changed the patient management who has been subjected to endovascular treatment, instead to the classical surgery.