Abstract
A 63-year-old man with a history of bilateral urinary stones was referred to our hospital for the evaluation of hyperparathyroidism. Although the diagnostic work-up showed no mass in the neck, 99mTc-MIBI scintigraphy demonstrated an abnormal accumulation in the mediastinum. Chest CT and MRI revealed an anterior mediastinal cystic mass measuring 3.0×2.2 cm. Video-assisted thoracic surgery was carried out to resect the tumor, which was suspected to be a functioning parathyroid cyst. Histological examination revealed a parathyroid adenoma in the wall of the cyst. The patient's serum calcium level returned to within the normal range, and he has followed a favorable course for three years since the operation. Although mediastinal parathyroid cysts are rare, they can cause hyperparathyroidism.
