Brain cavernous malformations

  • Learn more about the Cerebrovascular Surgery and Interventions Center.


    A cavernous malformation (CM), also called a cavernoma, is a small, berry-like mass that consists of an abnormally expanded, thin-walled blood vessel. CMs are among the more common cerebrovascular problems in children.

    While many people with CMs never notice any ill effects, CMs can cause neurologic symptoms and can sometimes be life-threatening.

    Most CMs are diagnosed after they have become symptomatic, by causing bleeding (hemorrhage) in the brain. The hemorrhage can be small and intermittent (subacute) or it can be large and rapid, causing a sudden onset of symptoms. Symptoms will vary depending on the CM’s location, but may include: 

    • weakness
    • sensory changes in an arm or leg
    • seizures
    • headaches
    • dizziness
    • irritability
    • changes in personality

    In most cases, symptoms gradually lessen as the blood becomes resorbed. In some cases, where the hemorrhage is large and exerts significant pressure on the brain, the child will have a faster recovery and a better outcome if the CM is surgically removed.

    If you have been diagnosed with a "cavernous malformation" outside of the brain, see the information on Venous Malformations.


    How we care for Cavernous Malformations at Boston Children’s Hospital

    In deciding how to treat CMs, we carefully evaluate each child with noninvasive head and neck imaging. If the CMs are not causing symptoms, many children do fine with a “wait-and-see” approach. If a CM has begun to bleed, we are more likely to recommend surgery if it is clearly the cause of the child’s symptoms. Surgery is the option of choice if there is a single CM in an accessible part of the brain that can be operated on safely. While some centers use stereotactic radiosurgery, we use it only as a last resort. After treatment, we follow each child every six months or annually with magnetic resonance imaging.

    In addition to treating the CM itself, Boston Children’s Hospital addresses any neurological symptoms it may have caused and provides close support to help children and families cope with any resulting disability.

  • Cavernous malformations (CMs) may be present at birth, but MRI scans have demonstrated that they can develop throughout life as well. Some patients develop CMs after radiation therapy for leukemia or brain cancer.

    Unlike brain arteriovenous malformations (AVMs), which have rapid blood flow coursing through them, CMs are fed by very small, low-flow blood vessels. They can range in size from something almost too small to see to a mass larger than an orange, and may grow over time.

    In studies based at Boston Children's, about 25 percent of patients had a strong family history of CMs, and a number of genetic mutations have been identified. A genetic component is likely if the child has multiple CMs, if there are associated blood vessel abnormalities on the skin, or if other family members have a seizure disorder or had brain hemorrhages at an early age. In these cases, we may suggest that siblings be evaluated for CMs.

    Once a CM is diagnosed, parents often want to know if physical activity will cause it to bleed. There is little evidence for this, and many patients with CMs lead normal, active lives. Nonetheless, we may suggest avoiding high-impact activities such as football.

    Click the Tests and Treatments tabs above to learn more.

  • Before treating cavernous malformations (CMs), the care team will conduct a variety of specific neurologic tests to assess brain function, in addition to imaging tests.

    At Boston Children’s Hospital, we use magnetic resonance imaging (MRI) and computed tomography (CT) to diagnose and evaluate CMs. Unlike most other cerebrovascular conditions, CMs are difficult or impossible to see on angiograms, because the blood flow within the malformations is very slow and because the vessels feeding them are so tiny.

    MRI produces 2- and 3-dimensional images of the head, neck and brain using a strong magnetic field, radio waves and advanced computer processing. It is noninvasive and uses no x-rays or radiation exposure of any kind.

    • The child must lie still inside an MRI scanner—a large, tube-shaped magnet—sometimes requiring her to be sedated. Sometimes a contrast dye is injected through an IV during scanning to get a better image.
    • In response to the magnetic field and the radio waves of the scanner, water molecules in the body give off tiny pulses of energy. A computer constructs detailed images out of these pulses, showing the head, neck and brain anatomy.
    • On MRI, CMs often have a very typical appearance, showing up distinctly from the surrounding brain tissue. The neuroradiologist often will be able to see areas of old and recent bleeding nearby.

    Read more about MRI.


    CT uses x-ray equipment and powerful computers to create detailed, cross-sectional images (often called “slices”) of the head, neck and brain. Most CT scans are performed in seconds, although it can take 10 minutes or longer to position the child correctly for the exam. It is noninvasive and highly accurate, and provides more detailed images of the bony and soft tissue structure of the head and neck than conventional x-rays. Read more about CT.

  • Many people with cavernous malformations (CMs) never notice any ill effects and do fine with a “wait-and-see” approach. If the CM has begun to bleed, we are more likely to recommend surgery. Surgery is a good option if there is a single CM that is clearly the cause of the child’s symptoms, and if it is located in a part of the brain that can be accessed and operated on without causing neurologic problems.

    Most children have excellent outcomes from surgery. Neurosurgeons at Boston Children’s Hospital use computerized guidance techniques to help locate CMs that are very small or deep within the brain.

    When a child has multiple CMs, the decision to perform surgery can require more detailed evaluation. It is sometimes hard to determine which particular malformation is causing the symptoms and whether the operation will reduce them. In this situation, it is sometimes safest to observe the child for a period of time and reevaluate her if symptoms recur. After treatment, we follow each child every six months or annually with magnetic resonance imaging.

    While some centers use stereotactic radiosurgery to treat CM, our team has found that this technique may not completely obliterate the CM, and symptoms may persist years after the treatment. Additionally, radiosurgery may lead to brain swelling that can be dangerous. For this reason, we use radiosurgery only as a last resort, when traditional surgery is too dangerous and symptoms become intractable.

    In addition to treating the CM itself, we bring together a team to address any neurologic problems it may have caused, including neurologists, physical/occupational therapists or speech-language therapists as needed.

  • The Cerebrovascular Surgery and Interventions Center at Boston Children’s Hospital conducts ongoing research to find better tests and treatments for cavernous malformations (CMs) and other cerebrovascular conditions.  Our clinical research is complemented by basic research on blood vessels in the Vascular Biology Program.


    CVD Dynamic Database

    Our comprehensive patient database, representing the largest experience with pediatric cerebrovascular disease (CVD) in the world, allows us to track long-term outcomes in our patients with CMs, evaluate newly adopted interventions and improve our quality of care.

    For example, we recently reviewed outcomes for 238 supratentorial lobar CMs in children coming to Boston Children’s from 1997 to 2011, of which 83 CMs were removed surgically. For those CMs that caused symptoms, 98 percent were completely removed, and 96 percent of patients with seizures were seizure-free at follow-up. Read an abstract of the study.

    3D printing to model brain and vascular anatomy

    Working with the Simulations group at Boston Children’s, Edward Smith, MD, and Darren Orbach, MD, PhD, are pioneering the creation of precision 3D models of patients’ brains and blood vessels, using data from their brain scans, to better understand their CVD condition and plan safe treatment maneuvers. The models are created with digitally guided 3D printers that lay down different types of molten plastic. Read more.



    CVD biomarkers

    Neurosurgeon Edward Smith, MD, is beginning to identify telltale proteins in the urine of patients with cerebrovascular disorders. These “biomarkers” may help in diagnosing and monitoring CVD, reducing the need for children to travel to Boston Children’s for follow-up imaging studies. Dr. Smith has already validated the utility of urine biomarkers of several kinds of brain tumors. Read more.

    See some of our published papers on CMs.

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