A difficult case of mediastinal parathyroid adenoma: theoretical and clinical considerations.

About one quarter of patients with primary hyperparathyroidism have ectopic parathyroid tissue. The majority of parathyroid glands can be reached through a cervical approach, but in about 2% of the cases the ectopic gland is in the mediastinum in a location that requires a thoracic approach. Failure to remove ectopic mediastinal parathyroid tissue results in persistent hyperparathyroidism. Reoperative exploration for persistent hyperparathyroidism is often difficult even in the hands of experienced surgeons. Recent advances in preoperative localization techniques and intraoperative parathyroid hormone measurement have improved the rates of successful resection. We present a difficult case of persistent hyperparathyroidism secondary to an ectopic middle mediastinal parathyroid adenoma, which was eventually successfully managed in a specialised unit.