Facial Infiltrating Lipomatosis Contains Somatic PIK3CA Mutations in Multiple Tissues.

INTRODUCTION: Facial infiltrating lipomatosis (FIL) is a rare congenital disorder that causes overgrowth of one side of the face, that can include premature dental eruption, hemimacroglossia, macrodontia, and mucosal neuromas. 1 We recently reported that affected subcutaneous adipose tissue in patients with FIL contains mutant cells with somatic gain-of-function mutations in PIK3CA. 2 The purpose of this study was to determine whether other affected tissues in FIL also contain mutant cells.