Parathyroid adenomas without sestamibi retention.

The authors describe two patients in whom parathyroid adenomas were successfully localized with a Tc-99m sestamibi/pertechnetate subtraction technique, but who did not exhibit differential sestamibi retention on delayed imaging. Although the frequency of this occurrence is unclear, it suggests that some parathyroid adenomas will be missed if reliance is placed on sestamibi retention alone without simultaneous thyroid imaging.