[Vascular anomalies. Part I: vascular tumors].

Vascular anomalies represent a spectrum of structural disorders and inborn errors of vascular morphogenesis, which may affect the entire arterial and venous vascular tree. They are divided into two major categories: tumors, which exhibit endothelial hyperplasia and malformations, which have normal endothelial turnover unless disturbed. Depending on their nature and complexity they can range from a simple "birthmark" to life-threatening entities. The relatively low incidence (4-10%) of vascular anomalies among the general population combined with the fact that their management often falls within the purview of several different medical and surgical specialties, has traditionally resulted in insufficient expertise in the management of these conditions. Therefore, accurate identification, a uniform nomenclature and a multidisciplinary approach are paramount for correct management.