Localization of an ectopic parathyroid adenoma by double-phase technetium- 99m-sestamibi scintigraphy

Double-phase planar scintigraphy using ^99mTc-MIBI has been introduced as a means to detect and localize parathyroid adenomas. Focal uptake on both early and delayed imaging is typical of these entities. We report a patient with persistent hypercalcemia following subtotal parathyroidectomy, who was found scintigraphically to have an ectopic parathyroid adenoma. Following initial detection within the mediastinum using planar scintigraphy, the adenoma was more precisely localized using SPECT imaging. This case suggests that double-phase parathyroid planar scintigraphy augmented with SPECT imaging, if needed, is cost-effective, and often necessary, in the assessment of primary hyperparathyroid patients before surgical reexploration.