eng Science and Education Publishing American Journal of Medical Case Reports 2374-216X 2018-10-23 6 10 202 203 10.12691/ajmcr-6-10-2 AJMCR20186102 article Ines Kechaou kechaou.ines@topnet.tn 1 Imene Boukhris 1 Mohamed Salah Hamdi 1 Eya Cherif 1 Lamia Ben Hassine 1 Narjess Khalfallah 1 Department B of Internal Medicine, Hospital of Charles Nicolle, University of Tunis El Manar, Tunis, Tunisia Brown tumors are rarely the presenting feature of the hyperparathyroidism and are usually accompanied by a disturbance of the calcium-phosphate balance. We report the case of a 46-year-old patient with no medical history, presenting a solitary bone lytic lesion linked to primary hyperparathyroidism. Phosphate and calcium balance was within normal range initially thus resulting in delayed diagnosis. Bone lesion has subsequently been confirmed to be a brown tumor. In front of solitary lytic bone lesion and even if phosphate and calcium balance was normal; the dosage of parathyroid hormone must be performed. http://pubs.sciepub.com/ajmcr/6/10/2/ajmcr-6-10-2.pdf brown tumor hyperparathyroidism normocalcemia hypercalcemia