Tehran University of Medical Sciences Acta Medica Iranica 0044-6025 54 8 2016 09 17 547 550 EN Habibeh Taghavi Kojidi Endocrinology and Metabolism Research Center, Endocrinology and Metabolism Clinical Sciences Institute, Tehran University of Medical Sciences, Tehran, Iran. Nazanin Vagharimehr Endocrinology and Metabolism Research Center, Endocrinology and Metabolism Clinical Sciences Institute, Tehran University of Medical Sciences, Tehran, Iran. Shahrzad Mohseni Endocrinology and Metabolism Research Center, Endocrinology and Metabolism Clinical Sciences Institute, Tehran University of Medical Sciences, Tehran, Iran. Mohammad Pajouhi Endocrinology and Metabolism Research Center, Endocrinology and Metabolism Clinical Sciences Institute, Tehran University of Medical Sciences, Tehran, Iran. Mohammad Reza Mohajeri-Tehrani Endocrinology and Metabolism Research Center, Endocrinology and Metabolism Clinical Sciences Institute, Tehran University of Medical Sciences, Tehran, Iran. 2016 09 14 2016 09 14 An ectopically placed parathyroid in the mediastinum is a rare cause of persistent or recurrent primary hyperparathyroidism. They are rarely in a huge size. We report a case of a 70-year-old man with a history of total parathyroidectomy and thymectomy presented with a lack of appetite, nausea, and generalized bone pain, polydipsia and a calcium level of 14.4 mg/dl. 99mTc-sestamibi scintigraphy with single-photon emission computerized tomography (SPECT) showed a focal zone of radiotracer accumulation in the midline of anterior chest wall (xiphoid level). The mass excised from our patient surgically was 75 grams. This weight and location of the tumor is a very rare finding in parathyroid adenomas. https://acta.tums.ac.ir/index.php/acta/article/view/5883 https://acta.tums.ac.ir/index.php/acta/article/download/5883/4829