Patient Content

Cavernous Malformations

Cavernous malformations are clusters of abnormal, tiny blood vessels and larger, stretched-out, thin-walled blood vessels filled with blood and located in the brain.
  • Brian Hoh, MD, FAANS,is the James and Brigitte Marino Family Professor and chair of neurosurgery at the University of Florida. Dr. Hoh specializes in cerebrovascular and endovascular neurosurgery, including the treatment of cerebral aneurysms, AVMs, cavernous malformations, carotid artery stenosis, stroke and moya moya disease.


Cavernous malformations are clusters of abnormal, tiny blood vessels and larger, stretched-out, thin-walled blood vessels filled with blood and located in the brain. These blood vessel malformations can also occur in the spinal cord, the covering of the brain (dura) or the nerves of the skull. Cavernous malformations range in size from less than one-quarter inch to 3-4 inches. Cavernous malformations are also referred to as cavernomas, cavernous angiomas, cavernous hemangiomas or intracranial vascular malformations. The term angioma implies a propensity for growth that is associated primarily with the familial form of the illness.



It is not known what causes cerebral cavernous malformations. About 20% of people with cerebral cavernous malformations have the familial form, meaning they inherited the condition. Researchers have identified genetic mutations that can cause cerebral cavernous malformations, such as the genes KRIT1 (CCM1), CCM2 and PDCD10 (CCM3).


A person with a cavernous malformation may experience no symptoms. When symptoms occur, they often are related to the location of the malformation and the strength of the malformation walls. The type of neurological deficit is associated with the area of the brain or spinal cord that the cavernous malformation affects. Symptoms may appear and subside as the cavernous malformation changes in size due to bleeding and reabsorption of blood. Any of the following symptoms may occur:

  • Seizures
  • Weakness in arms or legs
  • Vision problems
  • Balance problems
  • Memory and attention problems
  • Headaches


Cavernous malformations are part of a group of lesions known as “angiographically occult vascular malformations.” This means that they are not visible on an angiogram. Angiograms cannot visualize cavernous malformations, because blood flows through these types of lesions slowly. The relatively milder symptoms from the lesion, even when ruptured, are presumed to be related to this state of relatively low blood flow.

Magnetic resonance imaging (MRI), with and without contrast and with gradient echo sequences, remains the best means of diagnosing cavernous malformations. MRI scans may need to be repeated to analyze a change in the size of a cavernous malformation, recent bleeding or the appearance of new lesions.

When & How to Seek Medical Care

If you experience sudden symptoms such as sudden severe headache, seizure, sudden weakness in arms or legs, sudden vision problems, sudden balance problems, sudden memory and attention problems, seek medical attention immediately. If you are found to have a cerebral cavernous malformation, you should be referred to a neurosurgeon.


Asymptomatic Lesions

In general, lesions that are incidentally discovered should be followed with MRI scans annually for two years, then every five years thereafter. An MRI should be performed sooner if there is any clinical evidence of hemorrhage or new symptoms appear. Some patients may be prescribed anti-convulsant medications. This is an example of a subtype of AVM that may be monitored radiographically, specifically because the consequences of hemorrhage from these lesions are much less dire than those from classic AVMs or aneurysms.

Symptomatic Lesions

Surgery should be considered for seizure control if: 1.) Seizures cannot be controlled through medication; 2.) The cavernous malformation is in a low risk, easily accessible area of the brain; and 3.) It has been determined that the lesion is causing the seizures. If seizures are controlled through medication management, there may not be any compelling reason to perform surgery. In general, although seizures may indeed be cured by successful microsurgical removal, the primary goal of surgery is to prevent future bleeding and problems, such as seizures that may be associated. Seizure control by itself is not justification for performing microsurgery on a cavernous malformation.

Surgery may be indicated in patients who have experienced one neurologically symptomatic hemorrhage from a lesion in a low risk, easily accessible area. For lesions in eloquent areas of the brain, surgical removal should be contemplated in the context of surgical risk to nearby brain tissue, balancing this risk against the risk of bleeding to that same tissue in the event of a second hemorrhage.

Surgical removal should be considered in patients with progressive neurological deficits, but such neurological deficits can worsen after surgery. Although brain or spine surgery may carry substantial risk, so may hemorrhage into nervous tissue. The risk of surgery must be balanced against the risk of no surgery, on an individualized, case-by-case basis.

Note from AANS

The AANS does not endorse any treatments, procedures, products or physicians referenced in these patient fact sheets. This information is provided as an educational service and is not intended to serve as medical advice. Anyone seeking specific neurosurgical advice or assistance should consult his or her neurosurgeon, or locate one in your area through the AANS’ Find a Board-certified Neurosurgeon online tool.