Oral and perioral myofibromas and myofibromatosis: Clinicopathologic features of 79 cases

The clinicopathologic features of 79 myofibromas or myfibromatoses retrieved from the files of the AFIP were studied. There were 44 males and 33 females (2 unknown). The patient's age at diagnosis ranged from birth to 84 years with mean and median ages of 26.6 and 21 years, respectively. Four patients had infantile myofibromatosis, two with extraoral bone lesions, two with multiple subcutaneous tumors. Tumors involved, in descending order, the mandible, tongue, lips, cheek/buccal area, maxilla/palate, pterygomandibular raphae, floor of mouth, and submandibular gland. One third of the tumors affected the bones of the jaws; 12 central and 15 cortical or periosteal. All central tumors occurred in patients under age 18. Grossly, the lesions were firm, homogenous or whorled, white-gray masses that ranged in size from 0.5 to 5.0 cm. Microscopically, all tumors demonstrated a pattern of nodules or bundles of spindle cells separated by cellular zones and crescentic vascular spaces. Distinct pericytoma-like areas were present in 22 cases. Despite apparent circumscription, the tumors commonly infiltrated and entrapped adjacent muscle, nerve or salivary tissue. Among 66 cases with previous diagnoses 28 were interpreted as malignant or aggressive tumors and 29 as other benign conditions. Thirty-two patients were alive free of tumor an average of 42 months after initial diagnosis. Four patients had one recurrence and two had lesions recur twice. Myofibromas are relatively common soft tissue tumors of the maxillofacial region that have been misinterpreted as malignant or aggressive lesions.