Mediastinal parathyroid cyst with tracheal constriction.

A 63-year-old man visiting a physician for slight dyspnea, attributed to a lump on his neck, was found in ultrasonography and computed tomography to have a cyst extending from the left lobe of the thyroid gland to the superior mediastinum. Radiography showed right deviation of the trachea. The cyst disappeared after fine-needle aspiration, but cyst fluid subsequently reaccumulated and he was admitted to our hospital. No abnormalities were detected in tests of thyroid and parathyroid function or blood chemical analysis. The cyst was surgically removed and diagnosed as a nonfunctioning parathyroid cyst, based on the high-intact parathyroid hormone in cyst fluid. The patient recovered fully and has shown no recurrence in the 11 months to data since surgery.