What is an arteriovenous malformation?

An arteriovenous malformation often appears as a light vascular stain at birth, enlarging in early childhood or adolescence. The malformation is can be localized or diffuse. It is made up of connections between arteries and veins, lacking the tiny capillary networks that usually connect the two. Localized lesions are often found on the head and neck. Diffuse ones are most often found on the chest, abdomen or on a limb. These lesions become more noticeable with age. Lesions can also be found internally, including in the brain, lung liver or bowel.

Symptoms of arteriovenous malformations

At birth, arteriovenous malformations can appear as a light bluish ‘stain.’ The skin grows darker red or purple with age and a firm mass often appears. A pulse can often be easily felt by touching the mass. In some cases, however, there are no visible signs.

Risk factors of arteriovenous malformations

The cause of arteriovenous malformations is unknown.

Diagnosis for arteriovenous malformations

In addition to characteristic appearance and growth pattern, arteriovenous malformations are warm to the touch. Physical examination also reveals a pulse and bruit, a ‘whooshing’ sound heard through a stethoscope. MR angiography is often needed to determine the location of the core of the lesion and its extent.

Treatment for arteriovenous malformations

Small lesions that present no discomfort are often observed and monitored over time, requiring no treatment. Others may require intervention, including:


This highly specialized procedure involves the injection of small particles into the blood vessels to stop the flow of blood.

Surgical excision

Arteriovenous malformations may be removed surgically. If the core can be successfully removed, the lesion will not recur. This treatment is often combined with the embolization described above.