Congenital Infiltrating Lipomatosis of the Face: Recognition and Pathogenesis

Abstract

Congenital infiltrating lipomatosis of the face (CILF) is a well-defined but underrecognized entity. It occurs as an isolated condition or associated with hemimegalencephaly (HME) and neurocutaneous syndromes (particularly epidermal nevus syndromes), sometimes as part of “total unilateral hypertrophy.” Most reports of CILF from the past 20 years attribute the first description to Slavin et al in 1983[1]; however, this entity has been described for more than a century under descriptive terms of morphological appearance. It was first described by Beck in 1836 in a case of hemihypertrophy.[2] The second report, by Friedreich, involved only half of the face.[3] Another early report was also associated with hemicorporal hypertrophy, probably Proteus syndrome.[4] Slavin et al[1] introduced the term congenital infiltrating lipomatosis of the face, which is appropriate because it more specifically implies the nature of the lesion and has facilitated its recognition. However, “congenital hemifacial lipomatosis” would be more accurate to denote its marked asymmetry. Mild, moderate, and severe (sometimes massive) cases of CILF can be distinguished. Of the three cases reported by Slavin et al,[1] two were severe and one was mild. The pathologic examination of the lipomatosis of all three cases demonstrated nonencapsulated mature lipocytes with the following criteria: (1) infiltration of adjacent muscle and soft tissue; (2) absence of malignancy; (3) absence of lipoblasts; (4) presence of fibrous elements; (5) increased vessels with unifocally, thickened muscular walls; and (6) increase of nerve bundles with variable size. The lesion was congenital and recurrent after excision in all three patients. Their cases were isolated, and no neurologic or other systemic involvement was referred. Reports of CILF and HME without a concomitant neurocutaneous disorder are rare.