A case of myofibroma arising in the mandible

A case of mandibular myofibroma in a 11-month-old boy is described. Forty-six patients with maxillofacial myofibroma, including our case, have been reported since 1981. Among 42 patients, excluding 4 patients for whom age was not stated, 67% of the tumors occurred in those younger than 16 years old. We classified the patients into a pediatric patient group and an adult patient group, divided at 16 years old. Tumors arose in bone, including the mandible and temporal bone, in 71% of the pediatric patients, but in none of the adult patients. The mean tumor size in the pediatric patients was greater than that in the adult patients. Immunohistochemical staining was useful for establishing the diagnosis. Of the 32 cases for whom immunohistochemical findings were described, all were positive for α-smooth-muscle-actin and vimentin. However, all cases were negative for desmin and S-100 protein. No recurrence was reported among 20 patients for whom the outcome was described.