Transcervical video-assisted mediastinoscopy for resection of an ectopic parathyroid adenoma in the mediastinum: a case report

Background Mediastinal ectopic parathyroid adenoma (MEPA) presents significant difficulties in both preoperative localization and surgical management due to its deep mediastinal location and close relationship to critical surrounding structures. Traditional surgical approaches, such as median sternotomy or thoracotomy, are often necessary but are associated with considerable surgical morbidity. Currently, minimally invasive options for resecting deeply located mediastinal parathyroid lesions are limited and remain technically challenging. Case presentation We report a rare case of primary hyperparathyroidism (PHPT) in a 37-year-old male presenting with persistent hypercalcemia and elevated parathyroid hormone (PTH) levels, caused by a mediastinal ectopic parathyroid adenoma located in the aortopulmonary (AP) window. While initial imaging modalities failed to localize the lesion, it was successfully identified using 99mTc-sestamibi (99mTc-MIBI) SPECT/CT. The patient underwent transcervical video-assisted mediastinoscopy (VAM), and complete resection of the adenoma was confirmed via intraoperative parathyroid hormone (ioPTH) monitoring. The postoperative course was marked by transient hypocalcemia and rebound PTH elevation attributed to hungry bone syndrome. Following titrated oral calcium and calcitriol supplementation, sustained biochemical remission was achieved at the 3-month follow-up. Conclusions This case highlights the diagnostic challenges of mediastinal ectopic parathyroid adenomas, advocating for 99mTc-MIBI SPECT/CT for definitive localization when cervical imaging is inconclusive. Transcervical VAM offers a viable and advantageous, minimally invasive approach for accessing carefully selected lesions in the AP window, with ioPTH monitoring essential to confirm successful resection. Additionally, careful monitoring for postoperative hungry bone syndrome is necessary to ensure sustained biochemical remission.