The classification of vascular anomalies is controversial since the same terms are applied for different lesions. The biological classification according to Mulliken and Glowacki is based on the correlation of cellular features of vascular lesions during infancy and childhood with the physical examination and natural history. On this basis, two main categories of vascular anomalies can be distinguished: 1. Hemangiomas with endothelial proliferation and clinical course of rapid postnatal growth followed by slow involution. 2. Vascular malformations as developmental anomalies with normal endothelial cell cycles. These are subdivided according to the part of the vascular system involved.