Vascular malformation

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A vessel malformation (vascular malformation) is a malformation of blood or lymph vessels . Vascular malformations belong to the vascular anomalies. Various forms of vascular malformations include arteriovenous malformations , venous malformations, capillary malformations, and lymphatic malformations. Vascular malformations are congenital and show the course of life is often a size progression .

Classification

AVM of the brain in magnetic resonance imaging

One differentiates:

  • Arteriovenous malformations (AV malformations, AVM) : these are direct vascular connections between arteries and veins without a capillary bed. The arterial (oxygen-rich) blood comes from an artery and flows directly into a vein without the oxygen in it being consumed by tissues. With the appropriate size of the AVM, a not inconsiderable amount of blood volume can be transferred, whichcan become clinically relevantas steal syndrome .
  • Venous malformations (VM) : VM is the most common form of vascular malformation. In contrast to the AV malformations, it always has only a low blood flow. These are abnormally shaped and dilated veins. The wall of this canal system is unusually thin due to a lack of smooth muscle cells, but they are lined with endothelium . They are livid-blue, blood-filled and there is no parenchyma between the vascular spaces . Often thrombi are located within the cavernome.
  • Capillary malformations (KM) : These are vascular growths in the smallest blood vessels ( capillaries ). An example of a manifestation on the skin is the port-wine stain , in the digestive tract of Osler .

Clinical significance

Whether a vascular malformation is of clinical importance depends on the location, size and a possible bleeding tendency. AVMs can become hemodynamically relevant when there is very strong blood flow, and they are also at risk of bleeding. VM are of clinical importance primarily because of their space-occupying effect, but they can also lead to significant bleeding. Capillary malformations and lymphatic malformations are bothersome for cosmetic reasons, but mostly they are harmless.

Web links

  • ISSVA classification (PDF; 173 kB) Classification of vascular anomalies. Odile Enjolras, Michel Wassef and Rene Chapot: "Color Atlas of Vascular Tumors and Vascular Malformations", Cambridge University Press, 2007 (excerpt)