Efficacy of sequential double tracer subtraction and SPECT parathyroid imaging in the precise localization of a low mediastinal parathyroid adenoma successfully removed surgically

Abstract: The case of a 58-year-old female patient with primary hyperparathyroidism (serum calcium levels = 12.3 mg/dL, serum PTH levels = 254 pg/mL) resulting from a rare case of solitary parathyroid adenoma located in the low mediastinum is described. The sequential acquisition of planar Tc-99m pertechnetate-MIBI subtraction scan and SPECT imaging precisely localized an intra-thymic parathyroid adenoma located in the lower portion of the mediastinum anteriorly close to the body of the sternum. High-resolution 10-MHz neck ultrasonography and neck-mediastinum spiral computed tomography scan did not reveal parathyroid enlargement. A 14-mm sized intrathymic parathyroid adenoma was successfully removed through a 4-cm median cervicotomy by pulling up and excising the thymus. Thus, in this patient, the accurate preoperative scintigraphic localization of the parathyroid adenoma allowed the surgeon to avoid a sternotomy as is usually required in these cases. Intraoperative, rapid PTH levels fell to the normal range and serum calcium levels remained in the normal range in the subsequent 15-month follow up.