Solitary, multifocal and generalized myofibromas: Clinicopathological and immunohistochemical features of 114 cases

Aims: To report a large series of solitary and multiple myofibromas with systematic clinicopathological correlations. Methods and results: We report on 114 patients with myofibromas, 97 of which were solitary and 17 multifocal. The age at presentation ranged from newborn to 70years. All multifocal myofibromas and 91% of solitary myofibromas occurred in children. The head and neck region was the most common site (n=43), followed by the trunk (n=24), lower limbs (n=14), upper limbs (n=11), and viscera (n=4). Solitary and multifocal myofibromas stained positively for smooth muscle actin (SMA) in 95% and 92% of cases, muscle-specific actin (MSA) in 75% and 50% of cases, and desmin in 10% and 14% of cases, respectively. Regressive features were seen in 34 solitary myofibromas and in nine multifocal myofibromas. Most patients were treated with complete excision (n=79) or partial excision (n=12). There were no recurrences after treatment. Conclusions: Solitary and multiple myofibromas are benign tumours that predominantly occur in infancy and childhood. Myofibromas occur especially in the head and neck region, and are characterized by SMA and, to a lesser extent, MSA expression. The clinical course is self-limiting, and local excision appears to be sufficient.