Surgical resection of mediastinal ectopic thyroid tissue: a case series

Background: Ectopic thyroid tissue (ETT) is characterized by the presence of thyroid tissue in any location other than its normal anatomic position. Mediastinal ectopic thyroid gland is a rare entity, accounting for 1% of all ETT cases. In this article, we present seven cases with mediastinal ETT over the last 26 years admitted to Stanford hospital.Case Description: Searching Stanford pathology database for specimens that contained term "ectopic thyroid" between 1996 and 2021, a total of 202 patients were collected. Among those seven were classified as mediastinal ETT. Patients' electronic medical records were reviewed for data collection purposes. The mean age of our seven cases was 54 years on the day of surgery, and four were female. Chest pressure, cough, and neck pain were most reported presenting symptoms. Four of our patients had thyroid stimulating hormone (TSH) checks all within normal limits. All patients in our study had computed tomography (CT) imaging of the chest detecting the mediastinal mass. Histopathology of the mass revealed ectopic thyroid tissue negative for malignancy in all cases.Conclusions: Ectopic mediastinal thyroid tissue is a rare clinical entity that should be considered in the differential diagnosis of all mediastinal masses as it usually requires different management and treatment.