Vascular malformation, is a blood vessel abnormality. There are many types, but the most common is arteriovenous malformation. It may cause aesthetic problems as it has a growth cycle and can continue to grow throughout life. Vascular malformation, is a blood vessel abnormality. There are many types, but the most common is arteriovenous malformation. It may cause aesthetic problems as it has a growth cycle and can continue to grow throughout life.