Facial infiltrating lipomatosis.

Facial infiltrating lipomatosis is a rare congenital disorder in which mature lipocytes invade adjacent tissue. The phenotypic features include soft-tissue and skeletal hypertrophy, premature dental eruption, and regional macrodontia. There is a high risk for regrowth after resection that is, perforce, subtotal. The etiology, natural history, optimal management, and relationship to other disorders of fatty overgrowth are unclear. In this study, the clinical features, radiographic findings, histopathology, and postoperative results were analyzed in 13 patients with facial infiltrating lipomatosis. The condition was diagnosed in infancy (eight male subjects, five female subjects) and characterized by enlargement of the cheek (n = 12) or chin (n = 1). Other findings included cutaneous capillary blush (n = 9), ipsilateral macroglossia (n = 8), and mucosal neuromas (n = 6). Most patients had early eruption of ipsilateral deciduous and permanent teeth (n = 12). Computed tomography and magnetic resonance imaging showed an infiltrated soft-tissue mass of fatty density (n = 13) and skeletal overgrowth (n = 9). Multiple resection was performed on six patients (mean number of operations per patient, 2.5; range, one to six operations); regrowth and/or worsening of the capillary stain occurred in all six patients. Because surgical removal of the mass is usually unsuccessful, specific management of this condition will require insight into its etiopathogenesis. Given the presence of mucosal neuromas and lipomatosis, this study included testing for the known mutations in three entities that are associated with these soft-tissue findings (Cowden syndrome, Bannayan-Riley-Ruvalcava syndrome, and multiple endocrine neoplasia type 2B). Results of DNA analyses for these germline mutations were negative. It is more likely that this disorder is caused by a somatic mutation involving a local increase in growth factor(s).