The localization of abnormal mediastinal parathyroid glands

The venous drainage of parathyroid glands ectopically located in the mediastinum is generally caraniad into the inferior thyroid veins. Parathyroid glands in the neck can cause elevated concentrations of parathyroid hormone in mediastinal veins because of thyroidalthymic anastomoses. Therefore venous sampling alone cannot distinguish cervical from mediastinal adenomas. Arteriography can localize mediastinal parathyroids and should be perfomred before any repeat exploration.