Transcervical Resection of an Ectopic Mediastinal Parathyroid Adenoma

An 81-year-old man was incidentally found to have a posterior mediastinal lesion measuring 25 19 mm behind the trachea and lateral to the esophagus on computed tomography of the chest (Fig 1A, arrow). Parathyroid scintigraphy with Tc-MIBI (technetium with the ligand methoxyisobutylisonitrile) showed persistent focal activity in the posterior mediastinum along the left lateral aspect of the esophagus (Fig 1B, arrow). Bronchoscopic examination showed a protrusive mass beneath the membranous part of the trachea, which was remarkably elevated in the expiratory phase. The endobronchial ultrasound convex probe showed a multicystic posterior mediastinal mass with minimal vascularization by the Doppler mode imaging. The result of following endobronchial ultrasound–guided transbronchial needle aspiration of the lesion (Fig 1C, arrow), was consistent with a parathyroid tumor. Endocrinologic studies revealed a primary hyperparathyroidism with an intact parathyroid hormone level of 66.1 pmol/L (normal range, 1.3–7.6 pmol/L). The serum level of calcium indicated mild hypercalcemia (2.83 mmol/L) and the phosphate level was slightly decreased (0.65 mmol/L). A bone mineral density scan showed no abnormality.