Venous Malformations

A venous malformation is comprised of one or more atypically shaped, swollen veins. Surgical treatment of a venous malformation is not necessary in every case. When treatment is required, it most commonly consists of endovascular embolization or sclerotherapy.

Of the various blood vessel malformations that occur in the brain, venous malformations are among the least likely to need treatment. Typically they only require treatment if they exert a mass effect on the tissues around them, causing compression and compromising function.


Venous malformations are sometimes tender.

The veins in a venous malformation tend to function normally and thus to be asymptomatic despite their altered structure. However, an intracranial venous malformation that grows sufficiently large to affect surrounding tissues may generate symptoms indirectly.


Most intracranial venous malformations go undetected. They are sometimes found incidentally. If they are large enough to compress brain tissue and cause symptoms, they are found while physicians are searching for the cause of the symptoms.

Risk Factors

Venous malformations are relatively common. The estimated incidence in the general population of a venous malformation anywhere in the body is between 0.5 and 2.5 percent.

These malformations occur for reasons that are not yet understood. They are present at birth, but researchers have not identified any risk factors that may influence their development.


When a venous malformation requires treatment, physicians usually access the venous malformation endovascularly. A specialist inserts a microcatheter into a small incision near the hip and uses the body’s large blood vessels as a “highway” to approach the malformation. At the site of the malformation, the specialist may perform sclerotherapy or embolization to shut the vessels down.

Some malformations are treated directly by placing a needle through the skin directly into the lesion. An agent is injected into the lesion to cause it to close down.

A mixed vascular malformation (MVM) exists when venous malformations occur along with other cerebrovascular malformations, such as cavernous malformations. MVMs require treatment more often than straightforward venous malformations.

When a venous malformation is part of an MVM, treatment is usually only required if the other component of the MVM necessitates intervention. However, the surgeon must consider the venous malformation during surgical planning.