Venous malformations are congenital vascular dysplasias consisting of immature, vein-like vascular structures in which low blood pressure and low blood flow (“slow-flow”) are present. They present not as a single vessel malformation, but a sponge-like or tubular network of immature vascular arrangements that are filled with blood. Regardless of their location, as an early maturation disorder in vascular development, venous malformations often do not respect the normal tissue planes and may thus appear to be “infiltrating”.
Classic symptoms are local pain caused by locally mediated coagulation phenomena in the sense of thrombophlebitis, especially in the legs. In rare cases and when venous malformations are extensive, a specific coagulation disorder can also occur as a result of the continuous consumption of coagulation factors. The diagnosis is usually made clinically, supplemented by sonography and, if necessary, MRI. The therapy is interdisciplinary, depending on the extension, localization, and appearance and symptoms. Therapeutic methods range from compression to minimally invasive measures to surgery in individual cases. The patient must also take an active role in the treatment. Further details can be found in this chapter.