Beyond these multisystem disorders, mosaic mutations of PIK3CA have recently been identified in localized or focal forms of overgrowth with dysplasia including epidermal nevi (17), isolated macrodactyly (22), infiltrating lipomatosis (25, 46), isolated lymphatic malformations (28), and, most recently, venous malformations (29). The gene discussed is PIK3CA; the disease is lipomatosis.