BACKGROUND: We report a case of radioguided parathyroidectomy using a hand-heldgamma probe for the reexploration of primary hyperparathyroidism. CASE REPORT: The patient was a 66-year-oldJapanese woman. She had previously undergone surgical exploration for primary hyperparathyroidism dueto a left inferior parathyroid tumor detected by 99mTc-methoxyisobutylisonitrile (MIBI) scintigraphy.However, the pathological diagnosis of the resected tumor was adenomatous goiter. 99mTc-MIBI scintigraphywas performed again and revealed an abnormal uptake close to the right lower lobe of the thyroid. However,venous sampling for PTH measurements did not support this finding. Sestamibi was injected and the radioactivitywas measured pre- and intraoperatively with a hand-held gamma probe. With the patient under general anesthesia,the tumor, which was adjacent to the right recurrent laryngeal nerve, was resected, but it containedonly a low level of radioactivity ex vivo, indicating that it was not a parathyroid tumor. A hand-heldgamma probe accurately located the radioactive parathyroid tumor in the right lower neck. The resectedtumor measured 15 x 6 mm and weighed 331 mg. The pathological diagnosis was parathyroid adenoma. CONCLUSIONS:Radioguided parathyroidectomy is useful to localize parathyroid tumors not only in primary hyperparathyroidismat the initial neck exploration but also for reexploration.

Keywords: Adenoma, Hyperparathyroidism, Radiosurgery