Cavernous Malformation: 20 Questions & Answers

Cavernous malformations contain abnormal blood vessels. They consist of capillaries (the smallest blood vessels in the body). Blood moves through cavernous malformations very slowly. They look like raspberries and have very thin walls. Those thin walls can leak, and blood may enter nearby brain or spinal cord tissue. They are not cancerous but doctors sometimes call them vascular tumors because they can grow.

About one in every 500 people has a cavernous malformation, but most never have symptoms.

Most cavernous malformations occur in the cerebral lobes, the upper part of the brain. Cavernous malformations may also occur in the brainstem, the part of the brain that connects to the spinal cord. The spinal cord (spinal nerves) is the rarest place for a cavernous malformation that causes symptoms. Spinal cord and brainstem cavernous malformations can cause very severe symptoms and complications when they hemorrhage (bleed).

Cavernous malformations can cause different symptoms depending on where they are in the brain or spinal cord.

Seizures are one of the most common symptoms, especially when a cavernous malformation is in the cerebral cortex (the outer layer of the brain). Cavernous malformations in the brainstem or spinal cord do not directly cause seizures.

There are two main types of seizures:

• Focal seizures – start in one small area of the brain
• Generalized seizures – affect both sides of the brain

Seizures caused by cavernous malformations usually start as focal seizures. Sometimes they spread and become generalized. Doctors often use anti-seizure medications to control them. In some cases, if they know exactly which cavernous malformation is causing seizures, surgery or laser treatment may reduce or even stop seizures. Early surgery can help if medications do not work well.

Headaches are more common in people with cavernous malformations than in the general population. But headaches are very common in the general population, and a headache does not always mean a new bleed has occurred. A headache may be more concerning if it feels very different from your usual headaches or comes with new neurological symptoms.

Fatigue is common after a bleed or brain surgery. Some people feel tired for months or even years after a major bleed.

Learn more about CCM symptoms by location.

What is an incidental cavernous malformation?

Your doctor may have discovered your cavernous malformation when you had brain or spinal imaging for another reason. For example, you may have had a CT scan or an MRI after a car accident or concussion. When this happens, doctors call it an “incidental” finding.

Research has shown that incidental cavernous malformations that have never bled have a very low chance of causing problems. You may not need repeat imaging unless your doctor recommends it or you develop symptoms. 

If you have a single incidental cavernous malformation, discuss ongoing care with your doctor. If the cavernous malformation is in an area of the brain that has a higher risk of bleeding or causing symptoms, such as the brainstem, your doctor may recommend continued follow-up. For others, the decision may be based on comfort level and shared decision-making with your doctor.

If more than one cavernous malformation is found incidentally, it is a good idea to have regular follow-up visits with a doctor. This helps you maintain a relationship with a care provider in case you develop symptoms later. 

Surgery is not recommended for a cavernous malformation that has never caused symptoms.

Most cavernous malformations happen by chance and do not run in families. These are called sporadic cavernous malformations. 

People with this type usually have:

• Only one cavernous malformation
• No family history of the condition

Family members, including children, of a person with sporadic cavernous malformation are not more likely to have cavernous malformations than anyone else. 

To check for this condition, your doctor may order an MRI scan with a special type of image called susceptibility-weighted imaging (SWI). This type of imaging can help doctors see smaller cavernous malformations. If no additional cavernous malformations are found on SWI, this is reassuring that the person likely has a sporadic cavernous malformation. 

Some people have more than one cavernous malformation. This can happen for a few reasons:

• The most common reason is familial cavernous malformation. People with this condition are born with a higher chance of developing multiple cavernous malformations over time. Familial cavernous malformation is caused by a mutation (change) in the CCM1 (also called KRIT1), CCM2, or CCM3 (also called PDCD10) genes.
• Some people develop multiple cavernous malformations after radiation therapy for brain cancer.  
• A developmental venous anomaly (DVA) (also called venous malformation) can also cause multiple cavernous malformations. The cavernous malformations usually form near the DVA in the same area of the brain.

  

All cavernous malformations leak a small amount of blood very slowly. Doctors call this “oozing.” Oozing may not cause symptoms, but it gives cavernous malformations their typical “popcorn-like” appearance on an MRI scan.

Oozing is different from a symptomatic hemorrhage (bleed). A hemorrhage is more serious and can cause new or worsening symptoms. A person’s symptoms depend on where the malformation is, how big it is, and how much blood has leaked.

The biggest risk factors for bleeding are a previous bleed or a cavernous malformation in the brainstem. If a cavernous malformation has already bled once, the chance of another bleed is higher — especially in the first five years. After that, the risk slowly goes down over time.

A bleed that causes new symptoms, also called a symptomatic hemorrhage, is the most serious problem that can happen with a cavernous malformation. About 1 in 4 people diagnosed with this condition will have at least one bleed.

You may wonder if certain medications, like blood thinners, increase your risk. Current research shows that blood thinners do not seem to increase the risk of bleeding for most people. However, you should always talk with your healthcare provider before starting or stopping any medication.

Doctors recommend caution with hormone therapies that contain estrogen or progesterone. Some studies suggest these medicines may slightly increase the risk of bleeding. If you are thinking about using hormone therapy, talk with your doctor first. 

Research also shows that the following activities do not seem to increase the risk of bleeding:

• Exercise like walking, running, or other aerobic activity 
• Non-contact sports 
• Flying on commercial airplanes 
• Moderate use of alcohol or caffeine 

However, binge drinking should be avoided, and alcohol use should be discussed with your healthcare provider based on your personal health.

For the most up-to-date information, visit the hemorrhage section of the Alliance to Cure Cavernous Malformation website. If you have questions about your own risk, talk with your healthcare provider. They can help you understand what is best for your situation.

If you have symptoms, several healthcare professionals may help care for you. Your care team may include:

• Neurologist – A doctor who treats brain and nerve conditions. They help manage symptoms such as seizures, headaches, weakness, or pain.
• Neurosurgeon – A doctor who performs surgery on the brain and spine. They evaluate whether surgery may help remove a cavernous malformation or treat seizures.
• Physiatrist (Physical Medicine and Rehabilitation Doctor) – A doctor who helps people regain strength, movement, and function after a brain or spinal cord problem.
• Therapists – These specialists help with recovery and daily activities, including physical, occupational, speech, vision, and mental health therapy.
• Neuropsychologist – A specialist who tests and evaluates thinking, memory, learning, and emotions.
• Psychiatrist – A doctor who diagnoses and treats mental health conditions.
• Neuro-ophthalmologist – A doctor who diagnoses and treats vision problems related to the brain.
• Geneticist or Genetic Counselor – Specialists who evaluate whether a condition may run in your family. They also help families understand genetic testing and what the results mean.
• Dermatologist – A doctor who examines skin changes that can sometimes occur with the hereditary form of this condition.
• Orthopedist – A doctor who treats bones, joints, and the spine. They may monitor spine problems and help with mobility concerns.
• Perinatologist (Maternal-fetal medicine) – A doctor who manages high-risk pregnancies.

Not everyone will need all these specialists. Your care team will depend on your symptoms and personal situation.

Bring a written list of questions and mark your top 3–5. This helps the doctor answer the most urgent concerns first. You can always ask the remaining questions in later appointments or via the patient portal/email.

Top Priority (Ask at your next visit):

• How big is the cavernous malformation?
• How many cavernous malformations do I have?
• Where exactly is the cavernous malformation?
• Does the cavernous malformation show signs that it has bled before?
• What symptoms should I watch for that would require calling you or going to the ER?

Secondary Priority (Ask if time allows or at follow-up visits):

• What functions does this part of the brain control?
• Is there a developmental venous anomaly (DVA) near the cavernous malformation?
• If I have another bleed, what symptoms should I expect?
• When would you recommend surgery?

Optional/Long-Term Planning:

• How often should I follow up with you?
• How often will I need follow-up tests, and which tests will I have?

We will explore some of these questions in the following sections.

This is an important topic to discuss with your doctor. Some doctors recommend regular MRI scans. Others suggest waiting until new symptoms appear.

Experts often suggest more frequent imaging for people who may not be able to explain their symptoms, such as young children. These patients may need sedation to stay still during an MRI. You and your doctor will need to weigh the risks of sedation against the benefits of clear images.

CT scans are faster than MRIs but show less detail and use a small amount of radiation. They can be helpful in emergencies when an MRI is not available. However, MRI is still the best test for finding and tracking cavernous malformations.

In some cases, a doctor may recommend a cerebral angiogram to check for other types of blood vessel problems. If a cavernous malformation is clearly seen on an MRI, an angiogram is usually not needed.

If a cavernous malformation causes symptoms, you should talk carefully with a neurosurgeon about whether surgery is an option. Deciding on surgery means weighing the possible risks and benefits.

The most common treatment is open surgery. This is called a craniotomy when it involves the skull, or a laminectomy when it involves the spine. Doctors usually consider surgery after a second bleed or if the condition is causing seizures (epilepsy).

For some patients with epilepsy, newer, less invasive procedures may be an option instead of traditional open surgery.

Some neurosurgeons specialize in cerebrovascular (brain blood vessel conditions) and skull base (brainstem) surgery. It is important to learn about your surgeon’s experience with cavernous malformations. Getting a second opinion can also be helpful, especially from a designated CCM Center of Excellence or CCM Clinical Center.

Doctors have used a treatment called stereotactic radiosurgery — also known as Gamma Knife or CyberKnife — to treat cavernous malformations. It uses focused radiation aimed at the malformation without opening the skull.

However, researchers still do not know how well this treatment works. Doctors may recommend it for people who have one symptomatic cavernous malformation in a part of the brain where regular surgery would be too risky. Doctors do not recommend it for people without symptoms or those with the inherited form of the condition.

Researchers are also studying medications that may help keep cavernous malformations stable, lower the risk of bleeding, or slow the growth of new ones.

Right now, surgery is the only way to remove a cavernous malformation. However, physical therapy, occupational therapy, vision therapy, balance therapy, and mental health support can all help improve daily life.

About 80% of cavernous malformation cases occur by chance. Doctors call these sporadic cases. The other 20% run in families.

Genetic testing is most often recommended for people who have more than one cavernous malformation or who have family members with the condition. For people with only one cavernous malformation and no family history, genetic testing usually finds nothing.

You do not need to have other affected family members to consider testing. If doctors find a gene change, other family members — such as parents, siblings, and children — can also be tested to better understand their own risk.

This information can help with family planning and may allow people to take part in research studies. In the future, there may be treatments designed for specific gene changes.

Doctors do not believe women with cavernous malformations face an increased risk of bleeding during pregnancy. In most cases, they can have a vaginal delivery, especially if they have not had a recent bleed. However, it is important to talk through these decisions carefully with your doctors.

If your doctor recommends an MRI during pregnancy, it should be done without a contrast dye called gadolinium.

Women who take anti-seizure medications should talk with their doctors about whether their medicines need to change during pregnancy. Care decisions should be made with a medical team, which may include a perinatologist (high-risk pregnancy specialist).

If a cavernous malformation bleeds during pregnancy, treatment can become more complicated. In some cases, surgery may still be needed if waiting until after delivery would be too dangerous.

Learn more about pregnancy and cavernous malformation.

Young children may not be able to explain their symptoms. Because of this, doctors often rely on regular checkups and may suggest imaging tests over time. Finding the right balance between enough and too much testing can be challenging. Trusting your instincts and working with an experienced medical team can help.

As children grow older, they are better able to describe how they feel. Parents also become more confident in managing the condition over time.

Talking to your child about their diagnosis can be emotional. Try to explain things in simple, age-appropriate ways. A social worker or mental health professional can make these conversations easier.

Neuropsychologists can help address changes in learning after a bleed or surgery. An evaluation can identify your child’s strengths and challenges and guide support at school, at home, and in the community.

Getting a diagnosis of cavernous malformation in the brain or spinal cord can be difficult and upsetting for you or a loved one. Everyone needs time to adjust to a “new normal.” This may include grieving the changes in your life.

A counselor or mental health professional can help if your emotions make it hard to manage daily life. Friends and family may not always understand, especially if you don’t appear sick.

The Alliance to Cure Cavernous Malformation has an online community and weekly virtual support groups where you can meet others who share your experiences.

While researchers work toward a cure, there are some things you can do now that may help lower your risk:

Vitamin D
Inflammation can make cavernous malformations worse. Vitamin D helps reduce inflammation and supports your immune system. Studies show that low vitamin D levels may be linked to a more serious course of the disease. Your doctor can check your vitamin D with a simple blood test. If your levels are low, your doctor can recommend the right vitamin D supplement.

Diet
Research shows that the gut microbiome (the bacteria in your digestive system) may affect cavernous malformations. Protect your gut by avoiding foods with emulsifiers and artificial preservatives. Cutting back on processed foods is a good place to start.

Other Health Habits

• If you smoke or vape, try to stop.
• Avoid binge drinking.
• Stay up to date on vaccinations, like the flu shot and COVID-19 vaccines.
• Keep your heart and blood vessels healthy.
• Manage stress as best you can.

It’s a good idea to keep some of your medical records handy, especially when you travel or in case of an emergency. Make sure your emergency contacts understand what a cavernous malformation is and your medical history.

You might also consider:
Wearing a medical alert bracelet that says you have a condition that can cause bleeding in the brain or spinal cord.
Using a smartphone app to share important medical information with doctors or emergency personnel.

Living with a cavernous malformation can be hard. But there is hope. Researchers are studying new treatments that may help reduce symptoms and lower the risk of bleeding.

Research studies are already happening to test medicines and other treatments. Some of these trials focus on less invasive or non-invasive techniques.

You can find more information about joining these studies and learning about new treatments on our website. Research is ongoing to develop better treatments and, one day, a cure.

A diagnosis of cavernous malformation can feel overwhelming. Alliance to Cure Cavernous Malformation is a great resource for you and your family. You can meet other patients and families and learn more about the condition.

Even though cavernous malformation is rare, our online patient and family communities are large and growing. We are committed to supporting each other.