Abstract
Myositis ossification traumatica (MOT) has rarely been reported in the head and neck region. Heterotopic calcification occurs in masticatory muscle or soft tissue injured by trauma, tooth extraction, repeated infection, or mandibular nerve block. We report a case of a 21-year-old man with self-injurious behavior who developed MOT in the temporal and masseter muscles. The patient presented with severe trismus and facial swelling on the right side. Before surgical intervention, the maximal interincisal opening (MIO) was 5 mm. Preoperative computed tomographic (CT) images revealed the maturation of a calcified mass in the right masseter muscle during the previous six months. Partial resection of the right masseter muscle was performed under general anesthesia. During the operation, the MIO improved to 37 mm after the calcified tissue was removed. Histopathological analysis revealed the necrosis of ossified masseter muscle. Physical therapy was initiated the day after surgery. Postoperative CT imaging and 3-dimensional CT imaging showed the reduction of calcification in the right masseter muscle. Despite the operation, MOT developed in the right medial pterygoid muscle. Twenty-four months have passed following surgery, and an MIO of more than 25 mm has been maintained with no pain or facial swelling.
