A false-positive localization of a parathyroid adenoma with technetium Tc 99m sestamibi scan secondary to a thyroid follicular carcinoma.

Using technetium Tc 99m sestamibi for localization of a parathyroid adenoma in primary hyperparathyroidism, we describe the first reported case of increased uptake due to a thyroid follicular carcinoma. Prior false-positive results have been reported exclusively with follicular adenomas.