Vascular diseases in children are divided into two main groups: hemangiomas and vascular malformations. Hemangiomas in children typically progress in two stages: the proliferative stage and the involutional stage. Unlike hemangiomas, vascular malformations (abnormalities in the structure of capillaries, arteries, veins, lymphatic systems, or a combination of these) usually grow in proportion to the child's body and do not regress spontaneously.