Supernumerary ectopic parathyroid glands. Persistent hyperparathyroidism due to mediastinal parathyroid adenoma localized by preoperative single photon emission computed tomography and intraoperative gamma probe application.

Ectopic and/or supernumerary parathyroid glands are a major cause of persistent and recurrent Hyperparathyroidism (HPT). For this reason, it is widely accepted that preoperative localization should be performed to improve the surgical results in patients with persistent or recurrent HPT. Primary HPT (pHPT) was diagnosed incidentally in a 50-year old female patient during a preoperative examination for hernia. No pathologic parathyroid gland was detected in the preoperative Tc-99m Methoxybutylisonitrile (MIBI) scintigraphy and Ultrasonography (US). Cervical exploration was performed bilaterally. Four parathyroid glands were located adjacent to the thyroid gland. A fifth was detected in front of the cricoid cartilage. All five of them were of normal histology. Postoperatively, hypercalcemia persisted. Single Photon Emission Computed Tomography (SPECT) was performed before the second operation and radioguide surgery was carried out by median sternotomy. SPECT showed a parathyroid adenoma in the middle of the anterior mediastinum which was excised (size 1x0.5x0.5 cm) using a gamma probe. In conclusion, SPECT and intraoperative gamma probe application may help to detect the parathyroid adenomas, especially if they are small in size and buried in the adipose tissue. Such localization shortens the duration of the operation and reduces the possibility of complications.