Unilateral condylar hyperplasia of the mandible is a rare disorder that causes facial asymmetry and malocclusion. We report a case of active condylar hyperplasia in a patient who underwent a condylar reduction and orthognathic surgery simultaneously. A 28-year-old woman presented with facial asymmetry and cross occlusion of the left molar due to left condylar hyperplasia. A 99m Tc scintigraphy showed abnormal activity in the left condyle. After preoperative orthodontic treatment, a left condylar reduction and right intraoral vertical ramus osteotomy were performed simultaneously. The facial asymmetry and malocclusion improved, and 11 years after the surgery the patient shows no temporomandibular joint symptoms or recurrence.
