A vascular malformation is a blood vessel or lymph vessel abnormality. Vascular malformations are one of the classifications of vascular anomalies, the other grouping is vascular tumors. They may cause aesthetic problems as they have a growth cycle, and can continue to grow throughout life. Vascular malformations of the brain (VMBs) include those involving capillaries, and those involving the veins and arteries. Capillary malformations in the brain are known as cerebral cavernous malformations or capillary cavernous malformations (CCMs). Those involving the mix of vessels are known as cerebral arteriovenous malformations (AVMs or cAVMs). The arteriovenous type is the most common in the brain. Types
A simple division of the vascular malformations is made into low-flow and high-flow types. Low-flow malformations involve a single type of blood or lymph vessel, and are known as simple vascular malformations; high-flow malformations involve an artery. There are also malformations that are of mixed-flow involving more than one type of vessel, such as an arteriovenous malformation.Low-flow vascular malformations include capillary malformations, venous malformations, and lymphatic malformations. Capillary malformation
Capillary malformations involve the capillaries, and are the most common type. They used to refer only to port-wine stains but now include others. Capillary malformations are limited to the superficial layers of the skin but they can thicken, become nodular, and sometimes become disfiguring.
Cystic hygromas most often occur in the neck where they are known as nuchal hygromas.A severe venous malformation is known as a lymphaticovenous malformation that also involves the lymph vessels. Arteriovenous malformation
Arteriovenous malformations occur between an artery and a vein. In the brain a cerebral arteriovenous malformation causes arterial blood to be directly shunted into the veins as there is an absence of a capillary bed. This carries a high risk of an intracranial hemorrhage. See also
Arteriovenous fistula
Lymphohemangioma
Telangiectasia
Vascular disease


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