[Giant supernumerary parathyroid adenoma as a cause of persistent primary hyperparathyroidism in a patient with a multiglandular parathyroid disease].

Despite the significant progress that has been made in recent years in parathyroid imaging, improvements in surgical techniques and availability of surgical quality control based on intraoperative parathyroid hormone levels (PTH) assay, approximately 1-5% of patients undergoing surgery have state of persistent hyperparathyroidism. The most common causes of persistent hyperparathyroidism are: limited surgical experience, a failure to recognize multiglandular parathyroid disease, ectopic parathyroid adenoma location, insufficient range of resection of diseased parathyroid glands, parathyroid capsule tearing leading to parathyromathosis, as well as parathyroid cancer. In this clinical observation the case of a 52-years old man is described who underwent surgical removal of 2 parathyroid adenomas, and within few days he was found to have persistent hypercalcemia. After completing the diagnostic imaging and biochemical work-up that patient underwent bilateral neck re-exploration with removal of ectopic giant supernumerary parathyroid adenoma (60 mm in diameter and 22.8 g in weight) which was localized in the upper part of the posterior mediastinum, resulting in stable normocalcemia afterwards.