Overgrowth syndromes with complex vascular anomalies pose a challenge for diagnosis and management. The purpose of this descriptive study is to present a cohort of patients with congenital lipomatous overgrowth, vascular malformations, and epidermal nevi syndrome, a distinct clinical phenotype characterized by a complex truncal-lipomatous mass, vascular, acral, and other anomalies. This cohort was ascertained following review of patient data entered into the Vascular Anomalies Center database of the Children's Hospital, Boston over a period of 7 years. Clinical data, imaging findings, and the photographic archive were reviewed. The search identified 18 unrelated patients with a distinct phenotype. Variable portions of the truncal masses observed in these patients were composed of a lymphatic malformation. Capillary malformations and high-flow lesions were commonly encountered. The lipomatous mass infiltrated the adjacent anatomic spaces and was associated with capillary, lymphatic, venous, and arteriovenous vascular malformations. Paraspinal-intraspinal extension was associated with morbid sequelae. Acral deformities included large, wide feet and hands, macrodactyly, and a wide sandal gap. Scoliosis and other musculoskeletal, neurologic, renal, and cutaneous malformations were also encountered. The uniform and highly characteristic features of the truncal lipomatous mass, in combination with vascular, acral, and other anomalies, provide evidence of a distinct nosologic and clinical entity. Morbid sequelae of the truncal involvement in this condition can be deforming and disabling; hence, prompt diagnosis and multidisciplinary care are necessary.