ABSTRACT Coronoid Process Hyperplasia is a rare condition characterized by the increase in size of a histologically normal bone. It can be confused with Temporomandibular Joint Dysfunction, due to the presence of major signs/symptoms, including the limitation of mouth opening, pain, and facial asymmetry. Although several theories have been proposed, the etiology remains unknown. The recommended treatment is mandibular coronoidectomy. In the present study, the importance of computed tomography to reach the proper diagnosis and the surgical treatment plan is demonstrated.