Incidental Detection of Parathyroid Adenoma on 18F-PSMA PET/CT.

A 70-year-old man, diagnosed with prostate cancer, was referred to the Department of Nuclear Medicine for tumor staging with prostate-specific membrane antigen (PSMA) PET/CT. High PSMA uptake was observed in the prostate without PSMA-avid lymph nodes or distant metastases. Coincidentally, a PSMA-avid nodule was observed dorsal to the right thyroid lobe. A complementary 4-dimensional CT showed a round nodule of 18 mm with quick contrast enhancement well demarcated from its surroundings. Blood tests revealed elevated serum calcium and parathyroid hormone consistent with primary hyperparathyroidism. Subsequently, parathyroidectomy was performed, and histopathological examination of the nodule confirmed a parathyroid adenoma.