Vascular tumors consist of lesions secondary to endothelial hyperplasia, incorporating both hemangiomas and less common pediatric vascular tumors. Vascular malformations arise by dysmorphogenesis and exhibit normal endothelial cell turnover. Some anomalies may incorporate multiple areas of the vascular tree. Use of this division has provided a clinically useful method of diagnosis and prognosis, as well as a guide to therapy. It is hoped that with continued investigation into the biology and pathogenesis of these lesions, a more comprehensive molecular classification will soon be developed.