Cavernous malformations: What parents need to know

They’re among the more common cerebrovascular problems in kids. But few parents have heard of cavernous malformations until their own child is diagnosed. These small masses are comprised of abnormal, thin-walled blood vessels. While they can occur anywhere in the body, they’re most likely to cause problems when they form in the brain and spinal cord.

“Many different types of abnormal blood vessels can exist in the brain, but what makes cavernous malformations different is that they’re usually made up of very-low-flow blood vessels,” explains Dr. Edward Smith, co-director of the Cerebrovascular Surgery and Interventions Center at Boston Children’s Hospital. “This means that they can sit dormant for a very long time, but if they bleed, they can cause seizures and a host of other neurologic problems.” Here are four other things to know about cavernous malformations.

There’s often no known cause.

Cavernous malformations occur when small blood vessels in the brain called capillaries group together into enlarged or irregular masses. The vast majority of cavernous malformations are single lesions that are not genetically transmitted, with no real risk to any other family members. That said, a small percentage of cavernous malformations may be inherited when certain genetic mutations are passed from parent to child.

If a parent or sibling has a history of cavernous malformations, it’s a good idea to have your child screened for them.

Symptoms can come and go.

Cavernous malformations don’t always cause symptoms. When they do, it may be because the mass is getting bigger and putting pressure on the brain, which can lead to headaches, weakness, sensory issues or visual problems. If a cavernous malformation bleeds, your child may experience seizures, dizziness and irritability. These symptoms can wax and wane as the mass bleeds and then reabsorbs blood.

Head trauma is a big unknown.

In general, there are really no data to suggest that routine activity, sports or minor head trauma has any effect on cavernous malformations or bleeding. However, like any malformation in the brain — or any healthy brain, for that matter — high-velocity or repeated head impacts are probably unwise. “We often support kids playing most sports — basketball, baseball, soccer — but may suggest a commonsense restriction on activities such as football, boxing or certain martial arts,” says Smith. 

Most kids have excellent outcomes from treatment.

If your child doesn’t have symptoms, it’s possible your doctor may take a wait-and-see approach to treatment.

“Most of the time, I end up talking to families about what a cavernous malformation is and then counseling them on the ability of their child to live a full, normal life with no need for treatment,” says Smith. “If the mass looks particularly dangerous, we may think about doing an operation.”

Surgery is a good option if there is a single cavernous malformation that is clearly the cause of the child’s symptoms and is located in a part of the brain that can be easily accessed.

matty cavernous malformation
Matty underwent surgery by Dr. Edward Smith to remove a cavernous malformation from his brain.

Learn more about the Cerebrovascular Surgery and Interventions Center.