Mediastinal cystic parathyroid adenoma diagnosed by somatostatin receptor scintigraphy

A 71-year-old man complained of nausea and loss of appetite for eight months prior to admission. He was transported to a hospital with disorientation and diagnosed with primary hyperparathyroidism by laboratory examinations. However, ultrasonography, computed tomography, and technetium-99m labeled methoxyisobutyl isonitrile (^99mTc-MIBI) with single-photon emission computed tomography did not yield definite results. In contrast, somatostatin receptor scintigraphy successfully identified the lesion responsible for the oversecretion of parathyroid hormone within the middle mediastinum. The tumor was successfully resected by surgery, and a histopathological analysis confirmed the parathyroid adenoma nature of the tumor.