Abstract
A 61-year-old man presented to a hospital with swelling in the left supraclavicular region. Cervical ultrasonography revealed a cystic mass measuring about 5 cm in diameter in the left lobe of the thyroid gland and extending into the superior mediastinum. He was referred to our hospital with a diagnosis of mediastinal goiter. Cervical and chest enhanced computed tomography scan showed a multilocular mass in the left lobe of the thyroid, with a part extending into the mediastinum. We performed left hemithyroidectomy for the mediastinal goiter. Macroscopic examination of the resected specimen revealed a cystic tumor measuring 5.9 × 4.8 cm in the left lobe of the thyroid. Pathological examination revealed the large cyst with neighboring multiple cysts ; internal surface of the cyst was covered with stratified squamous epithelium and there were numerous lymphatic follicles with germinal centers beneath them. The lesion was diagnosed as lymphoepithelial cyst in the thyroid gland, this being a rare location for such cysts. No malignancy was evident. We herein report a case of lymphoepithelial cyst extending into the superior mediastinum.
