SPECT and subtraction imaging of an ectopic parathyroid adenoma.

Primary hyperparathyroidism is a disease best managed surgically; resection of the lesion(s) is curative. Although the routine use of localizing procedures is controversial before surgery, it is generally agreed that these techniques are useful in cases of reexploration. The authors have recently studied a patient with long-standing hyperparathyroidism, in whom initial surgery was unsuccessful. Although planar imaging with Tc-99m sestamibi is usually sufficient for identification and localization of the lesion, both SPECT and subtraction imaging provided additional information that contributed to the success of the subsequent surgery. Single-proton emission computed tomography provided critical information about the position of the ectopic parathyroid adenoma in relation to the right submandibular salivary gland, whereas subtraction imaging confirmed that the focus was indeed a parathyroid lesion, and not merely an anatomic variant of a normal salivary gland.