Unilateral hypertrophy of the masseter muscle: report of a case

An 18-year-old man with unilateral hypertrophy of the masseter muscle is reported. The patient complained of a painless swelling on the left side of the face. On palpation, there was an evident asymmetry of the masseter muscles and remarkable hypertrophy of the left masseter muscle associated with deformity, and lateral deviation of the mandible was revealed by CT scans.The lower and inner portion of the left masseter muscle was resected and the expanded portion of the lateral cortical plate was trimmed away by an intraoral approach. There was no complication except slight paresthesia of the left cheek skin. Postoperative CT scans showed that the asymmetry of the face and the mandible was greatly improved. The patient was satisfied with the result of surgical correction.