Classification of venous and lymphatic malformations according to the description of the International Society for the Study of Vascular Anomalies is based on clinical and MRI appearance. Although possible limitations exist, it should be carried out for treatment decisions. Treatment modalities include the use of sclerosing agents directly introduced by percutaneous puncture (Ethibloc, Thrombovar, Ethanol in venous malformations or Picibanil in macrocystic lymphatic malformations), laser-induced thermal therapy, surgery, or a combination of different techniques. A promising substance for treatment of venous malformations is an Ethanol mixture with Ethylcellulose at a higher viscosity, which is under evaluation in a multicenter-study.