A case of mediastinal ectopic thyroid presenting with a paratracheal mass
A 65-year-old male presented with a right paratracheal mass, incidentally detected on a computed tomography (CT) scan performed during a health examination after a traffic accident (). No evidence or symptoms of thyroid dysfunction were found. The patient had had hypertension for several years. He had no history of exposure to radiation, and there was no family history of thyroid disease. His thyroid was not palpable, and there was no evidence of cervical lymphadenopathy. The results of his laboratory tests were all within normal limits and included a thyroid stimulating hormone level of 0.96 mU/L (normal range, 0.40 to 4.00), T3 of 1,090 pmol/L (normal range, 600 to 1,950), and free T4 of 11.2 pmol/L (normal range, 7.8 to 19.4). The titers of serum thyroid autoantibodies were also within normal ranges; antithyroid peroxidase antibody was < 25 U/mL (normal range, < 100) and antithyroglobulin antibody was < 25 U/mL (normal range, < 100).\nA CT scan of the neck () revealed a 4.5 × 2.9 cm heterogeneously enhanced mass in the right paratracheal area. The mass was located at the intersection of the caudal margin of the left brachiocephalic vein and the trachea, and it compressed the superior vena cava. However, there were no symptoms related to the compression. The thyroid gland was located in the normal position and showed slightly heterogeneous enhancement and no cervical adenopathy. There were no focal nodules in either lobe.\nEndobronchial ultrasound (EBUS) () and EBUS-transbronchial needle aspiration were performed to obtain a tissue sample of the paratracheal mass. During EBUS, the large mass was observed as a right upper paratracheal lesion (2R lesion). The radiologic diagnosis of the mass by EBUS was metastatic adenopathy, Castleman's disease, or tuberculous lymphadenitis. Biopsies of the mass showed normal thyroid follicles ().\nExcision of the ectopic thyroid tissues was recommended to the patient. Recently, he had undergone a coil embolization for an aneurysm in his left posterior communicating artery; he is now waiting for the ectopic thyroid tissue to be surgically excised after his general condition has stabilized.