Cavernous Malformations

What are cavernous malformations?

Cavernous malformations are tightly packed clusters of tiny blood vessels (capillaries) whose walls are thinner, weaker and less elastic than normal. The capillary walls stretch out easily and do not return to their normal shape and size. Instead, they bulge, forming “caverns,” or pockets, that fill with slow-moving blood.

When these clusters of blood vessels form in the brain, they are called cerebral cavernous malformations (CCMs). Most happen in the upper part of the brain (cortex).

  • Where else do cavernous malformations form?

    Cavernous malformations can also form in:

    • Other brain regions, such as the brainstem
    • The dura mater
    • The spinal cord
    • Other parts of the body
  • What problems are linked with these malformations?

    Compared to normal capillaries, CCMs can bleed easily, which may cause symptoms, such as headaches or seizures, or lead to stroke.

    Overall, most people with CCMs never have symptoms or related health problems. As a result, many people have CCMs without ever knowing it.

    Because CCMs may cause mild-to-serious symptoms or no health problems at all, doctors and families need to weigh many factors carefully when deciding whether a child’s CCM needs treatment and which treatment is best.

  • Are children born with cavernous malformations?

    Cavernous malformations may be present at birth (congenital) or form sometime after birth.

    The chance of having a CCM seems to increase throughout childhood: the older a child is, the more likely doctors are to see a CCM on a scan of the nervous system, such as an MRI (magnetic resonance imaging).

    About 1 in 200 adults has a CCM.

  • Can children have more than 1 lesion?

    Some children with CCMs have only 1 cluster of abnormal blood vessels (sometimes called a lesion). Other children have many lesions. The number of lesions can change over time. The size of a lesion can also change, which may range from ¼ inch to 4 inches across.

  • Is this condition passed down in families?

    About 90% of children with CCMs have no family history of the condition. These cases are called sporadic. Most of these children have only a single lesion.

    Doctors have found some genes that cause CCMs to be passed down in families (genes CCM1/KRIT1, CCM2/MGC4607 and CCM3/PDCD10). People with CCMs passed down in families (familial CCMs) are more likely to have more than 1 lesion. They have a 50% chance of passing the condition on to each of their children. Seattle Children’s genetic counselors can provide information and guidance to families who are at risk.

  • Other names for this condition

    Cavernous malformations are also called:

    • Cavernomas
    • Cavernous angiomas
    • Cavernous hemangiomas
    • Capillary hemangiomas
    • Intracranial vascular malformations.

Cavernous Malformations at Seattle Children’s

Seattle Children’s treats many children with CCMs each year. We see patients from babies to young adults and can provide all aspects of care – from diagnosis to surgery to long-term follow-up. We also provide second opinions.

  • The experts you need are here

    Your child will be cared for by a team of CCM experts, including specialists from Neurosurgery and Neurology.

    Neurosurgery experts

    Drs. Richard G. Ellenbogen and Jeffrey G. Ojemann and others from Neurosurgery have special expertise in:

    • Telling whether a child needs surgery to remove CCMs
    • Performing the surgery
    • Using advanced techniques, like fMRI (functional magnetic resonance imaging), to map brain function so your child’s surgery is as safe as possible

    We are one of the only pediatric centers in the Pacific Northwest to offer fMRI.

    Pediatric Vascular Neurology Program

    Seattle Children’s has the region’s only Pediatric Vascular Neurology Program. The program is led by a doctor who specializes in blood flow to the child’s brain, Dr. Catherine Amlie-Lefond. Children with suspected or diagnosed CCMs are often seen by Amlie-Lefond, who does a complete neurological evaluation and plans further evaluation.

    Epilepsy Program

    For children with seizures, the most common symptom of CCMs, Seattle Children’s has the largest pediatric Epilepsy Program on the West Coast. Our epilepsy experts will make sure your child has the best chance to be seizure free.

    Team approach

    Each child with a CCM is unique. Based on your child’s needs, your team may include specialists from NeuropsychologyRehabilitation MedicineOphthalmologySocial Work and other areas. Your whole team works together to explain your child’s condition and treatment and to answer your questions so you know what is happening and what to expect.

  • We treat infants, children, teens and young adults

    At Seattle Children’s, we diagnose and treat people with CCM from birth through young adulthood, up to age 21. We see people who:

    • Have symptoms and imaging studies that suggest they might have a CCM.
    • Have been diagnosed and may need surgery or another treatment. (Some have had no CCM symptoms, but they had a brain scan for another reason that revealed the CCM.)
    • Had treatment somewhere else for CCMs and have moved to the Northwest, want to change doctors or want a second opinion about the best treatment.

    We have the specialized equipment and expertise needed to treat babies, children, teens and young adults.

  • Your child gets long-term care and support

    We take care of your child over the long term — not only in the weeks and months right around getting a diagnosis and receiving initial treatment, but for years to come. We provide follow-up care to:

    • Monitor your child’s health
    • Prevent complications
    • Manage symptoms or other health problems
    • Give your child the best quality of life

    Dealing with CCMs can be stressful. Social workers, child life specialists and many others are available to provide support for you and your child.

Symptoms of Cavernous Malformation

Cavernous malformations usually cause symptoms only if they form in the brain or spinal cord (central nervous system). Even in these locations, symptoms are not common.

Among children who are diagnosed with CCMs, about half have symptoms that led to the diagnosis.

  • General symptoms

    Symptoms of CCMs include:

    • Seizures
    • Headaches
    • Weakness or paralysis in arms or legs
    • Vision problems
    • Hearing problems
    • Speech problems
    • Balance problems
    • Thinking, memory and attention problems
  • How bleeding can cause symptoms

    Sometimes symptoms happen when CCMs bleed because bleeding can:

    • Put pressure on nearby tissue
    • Irritate the tissue
    • Prevent oxygen-rich blood from getting to brain cells that need it (stroke)

    The blood inside CCMs is under low pressure. So, often when CCMs bleed, they bleed only a small amount. Sometimes bleeding is severe. Even a small amount of bleeding can be dangerous in a part of the brain that controls important functions.

    Often, symptoms relate to the location, number and size of the CCMs.

    Symptoms may come on gradually or quickly. They may come and go as the CCM bleeds and then the body reabsorbs the blood.

    Some children with symptoms caused by a bleed never have symptoms again. Some have frequent rebleeding and symptoms that come back or get worse.

Diagnosing Cavernous Malformations

The doctor will ask about your child’s medical history and examine your child. Your child may need an MRI (magnetic resonance imaging) and, in some cases, other tests.

  • MRI

    The best way to see and diagnose a CCM is with MRI. The lesion (cluster of abnormal blood vessels) and substances left behind from repeated bleeds may look like tiny popcorn or a raspberry on the scan.

    Doctors may repeat MRIs over time to look for changes, like these:

    • A new lesion
    • A change in the size of a lesion
    • Recent bleeding
  • Tests to find the problem lesion

    If your child has CCM symptoms and more than 1 lesion, the doctor may ask for other tests to help pinpoint which lesion is causing the symptoms. For example, if your child has seizures, Seattle Children’s has a great deal of experience using imaging to diagnose epilepsy and find out where in the brain a seizure begins.

  • Genetic tests

    Genetic tests can be done to check for gene changes (mutations) known to cause forms of CCMs that can be passed down in families. Our neurologists and geneticists work together to diagnose this form of the condition. They can explain and perform the tests and counsel you about what the results mean for your family.

  • Diagnosing children who have no symptoms

    Many children with CCMs have no symptoms and never know they have the condition. Some are diagnosed only because the CCM shows up on imaging scans done for some other reason — not because of a health problem related to the CCM.

Treating Cavernous Malformations

Treatment for CCMs is tailored to your child and depends on many factors, including: 

  • The effects of the CCMs on your child so far
  • The risks of bleeding and future health problems if the CCMs are left alone
  • How effective medicines are at treating any symptoms your child has
  • The benefits and risks of surgery

Your child’s team at Seattle Children’s will talk with you in detail about what they recommend for your child and why.

  • Medicine for cavernous malformations

    There is no medicine to get rid of CCMs, but medicines may help with symptoms that CCMs cause. Medicines may treat seizures or relieve headaches.

    Anti-seizure medicines help most people with epilepsy, but they do not always control seizures caused by CCMs.

    Seattle Children’s Epilepsy Program is the largest program on the West Coast dedicated to treating children with seizures. Our doctors, nurses and other specially trained staff are experts at understanding childhood epilepsy and finding the most effective treatment for each child.

  • Surgery for cavernous malformations

    Surgery to remove a CCM may be an option to control seizures that do not respond to medicine. Surgery might also be an option to reduce the risk of future health problems the CCM may cause.

    Seattle Children’s neurosurgeons have special expertise in removing CCMs and using the brain-mapping tools that make this surgery as safe as possible.

    Deciding on surgery

    We consider surgery for children with CCMs on a case-by-case basis. Each child is different, and it is important to carefully weigh the possible benefits and risks for your child.

    Our neurosurgeons consider many factors, including these:

    • Whether your child’s lesion is getting bigger
    • Whether doctors believe your child’s CCM is at high risk of bleeding
    • Whether your child has repeated seizures that are not controlled with medicines
    • Whether doctors can tell which lesion is causing your child’s symptoms (if your child has more than 1 lesion)
    • Whether the lesion is in a place that makes it more likely or less likely to bleed (or rebleed) if left alone
    • Whether neurosurgeons can safely get to the lesion to remove it
    • What the risks of surgery may be to nearby healthy tissue

    Mapping brain function

    Before surgery, we use advanced techniques, like MRI (magnetic resonance imaging) and fMRI (functional magnetic resonance imaging), to pinpoint important brain areas near the CCM. We use these methods to:

    • Help decide whether to recommend surgery
    • Tell which areas to avoid during surgery to reduce the risk of problems with talking, moving or other functions

    During an fMRI scan, we ask your child to do something, like tap their finger, look at pictures, read or listen to words. This allows us to see which parts of the brain are being used during these tasks. The tasks we ask your child to do are tailored to their age and abilities.

    If needed, our neurosurgeons perform surgery to place (implant) electrodes on the surface of your child’s brain for a few days to identify critical areas, a process called electric brain mapping (electrocorticography, ECoG). ECoG can also be used to look for clues to a child’s seizures. ECoG is also known as intracranial electroencephalography, or iEEG.

    Sometimes the best way to protect language and motor functions is to wake your child up during the surgery to remove their lesions. The neurosurgeon uses a small electric current to briefly cause brain activity in specific areas. If this disrupts an important function, we know this function is controlled by this area and we should avoid it. This does not cause any pain for your child.


    To remove a CCM, the neurosurgeon performs a surgery called craniotomy, using a microscope to see fine details of the lesion.

    If neurosurgeons cannot safely reach the lesion with craniotomy, some treatment centers have tried radiosurgery. We do not use this method at Seattle Children’s because it has not proved to be a good way to cure CCMs or their symptoms and the radiation can lead to significant problems, such as neurologic deficits.

    Care after surgery

    After surgery for a CCM, many children leave the hospital within a few days and return to their normal life and activities within a few weeks. Some children are cured of their CCM and any related seizures or other symptoms with no neurological deficits.

    Children who had neurological deficits before surgery may get back to the same level of function after surgery with rehabilitation services, like physical therapyoccupational therapy and speech and language therapy; some may improve their function even more.

    Seattle Children’s provides a full range of care for children with CCMs, including rehabilitation for those who need it and long-term follow-up.

Contact Us

If you would like an appointment, ask your child’s primary care provider for a referral. If you have a referral, call 206-987-2016 to make an appointment.

Providers, see how to refer a patient.

If you have questions, contact us at 206-987-2016 or 844-935-3467 (toll free).