False-positive parathyroid scan leading to sternotomy: Incidental detection of a thymoma by C-11 methionine positron emission tomography

Abstract

SURGICAL EXPLORATION REMAINS the principal method of localizing abnormal parathyoid glands in primary hyperparathyr0idism.l A variety of preoperative imaging studies have been used to assist in the preoperative localization of parathyroid adenomas and hyperplastic parathyroid glands. These include computed tomography, ultrasonographp arteriography, selective venous sampling, magnetic resonance imaging, thallium-201 thallous chloride/technetium-99m pertechnetate, and technetium-99m sestamibi.2-7 These methods focus on developing a practical, reliable method of visualizing aberrantly located parathyoid tissue to avoid unnecessary neck reexploration and to determine before operation the need for mediastinal exple ration. Recently, positron emission tomography (PET) has been proposed as an imaging technique for detecting a variety of tumors in the cervical region including squamous cell carcinoma,d thyroid carcinoma,g and parathyroid adenomas.‘, lo Neumann et a1.l evaluated 17 patients with hyperparathy roidism by using PET in conjunction with the glucose analog and [F-18] 2-deoxy-2-fluoro-D-glucose (FDG) and correctly identified 17 of 1s parathyroid adenomas. There were three false-positive