Incidentally detected ectopic thyroid in juxta cardiac location—Imaging and pathology

Abstract

Ectopic thyroid gland is a developmental anomaly that results from the arrest of thyroid tissue along its path of descent from the floor of mouth to the pre tracheal position in the lower neck. It is typically found along the thyroglossal duct with the base of the tongue being the most common site. Apart from mediastinal extension of goiter, the incidence of true intrathoracic ectopic thyroid tissue is rare. Presence of ectopic thyroid has been reported not only in the chest but also in the abdomen and pelvis. Pericardial and intracardiac locations are extremely uncommon and right ventricle location is predominant among the described cases. We describe a case of incidentally detected ectopic thyroid tissue in a rarer location—adjacent to the left atrium. The patient, who had undergone a nephrectomy for renal oncocytoma 5 years ago, presented with unintentional weight loss and left sided flank pain, prompting a workup to rule out abdominal malignancy. Findings on the computed tomography (CT) scan of the abdomen and pelvis prompted further investigation including a chest CT which showed a heterogeneously enhancing mass near the left atrium. Given its location, further radiological investigations played an important role in eliminating the differential diagnosis of paraganglioma. The mass was surgically resected and discovered to be a hyperplastic thyroid nodule on histologic examination.

Ectopic thyroid tissue: An unusual cause of intracardiac mass

“…Typically, the location and function of the cer- scan. 9 In addition, when other pathological changes such as adenoma occur in ETT, the enhancement can become inhomogeneous.…”

“…Although thyroid radionuclide imaging is considered the best way to diagnose ETT, it should be noted that ETT does not ingest radionuclides when it is nonfunctional or hypofunctional. 9 Moreover, thyroid radionuclide imaging is easy to be ignored because the patient is admitted with an intracardiac mass. and thyroid gland should be carefully examined postoperatively to exclude cardiac metastasis from thyroid cancer, especially follicular thyroid cancer.…”

“…The CT findings of ETT are similar to those of normal thyroid tissue, with high density on plain scan and obviously homogeneous enhancement on the enhanced scan. 9 In addition, when other pathological changes such as adenoma occur in ETT, the enhancement can become inhomogeneous.…”

“…Although thyroid radionuclide imaging is considered the best way to diagnose ETT, it should be noted that ETT does not ingest radionuclides when it is nonfunctional or hypofunctional. 9 Moreover, thyroid radionuclide imaging is easy to be ignored because the patient is admitted with an intracardiac mass.…”

Ectopic Thyroid Tissue Masquerading as a Functional Carotid Body Paraganglioma

“…It is frequently found along the course of the thyroglossal duct with the most common location being the base of tongue, also known as lingual ETT. Rarely, it can also be found laterally in the neck, as well as in distant locations such as the mediastinum, chest, abdomen, and pelvis (1,2). Although most cases are asymptomatic, symptoms related to its functionality, size of the ETT, and its relationship with surrounding tissues may illuminate its existence.…”