Cavernous Malformations

Cavernous malformation
The tangle of capillaries in a cavernous malformation may leak and create small “caverns” of blood within the brain.

A cavernous malformation (also called a cavernoma, cavernous angioma, or a “cav-mal”) is a rare type of vascular malformation, meaning an abnormality of the blood vessels. A cav-mal can occur in any part of the body, but it’s usually only a threat in the brain or spinal cord. When it occurs in the brain it’s known as a cerebral cavernous malformation, or CCM. 

A CCM consists of a tangle of capillaries (the small blood vessels that carry oxygen-rich blood deep into the brain) in which the vessel walls are thinner and less elastic than normal, and more prone to leaking. That leakage can create small “caverns” of blood within the brain. It occurs equally in women and men and can be diagnosed at any age, but it is most likely to be detected in young adults.

A cav-mal may remain stable for decades and never cause any symptoms at all. Some people only discover that they have a cavernous malformation when they have an MRI scan for some other reason, such as after a car accident or other injury (an “incidental” finding). In those individuals, no treatment at all may be needed.

But a cavernous malformation may begin to leak (hemorrhage) intermittently over the course of months or years. In some people, the cav-mal causes symptoms that get worse with each small hemorrhage, then gradually get better as the leaked blood is reabsorbed, only to worsen again with the next hemorrhage. The malformation usually grows slowly over time, enlarging with each small hemorrhage. (See Symptoms of a Cavernous Malformation.)

In other cases, a cerebral cavernous malformation may cause substantial bleeding in a single episode, with significant hemorrhage leading to severe neurological deficits or even death. If the cav-mal is located in the surface layer of the brain (the cerebral cortex), it may also cause seizures.

The prognosis for a cav-mal is different for each individual, based on the size and location of the malformation and on its tendency to hemorrhage or not.

Watch CBS News New York: Dr. Stieg and his patient Kyle McMorrow talk about the brain bleed from his cavernous malformation that brought on an unexpected stroke when he was just 36 years old.

Watch Dr. Stieg and Kyle McMorrow on PIX11

What Causes a Cavernous Malformation?
Cavernous malformations can be considered sporadic or familial. Individuals with sporadic cavernous malformations do not have a family history of the condition and tend to only have one cavernous malformation. This differs from familial cavernous malformations, in which an individual has either a family history of cavernous malformations, more than one malformation identified, or a known genetic cause.  About 80 percent of familial cases of cavernous malformations have an identifiable genetic connection. 

Individuals with a family history of cavernous malformations or multiple malformations are recommended to consider genetic counseling and genetic testing to evaluate the cause of their symptoms and to evaluate their family risk. Additionally, because many individuals with cavernous malformations never experience any symptoms, there may be individuals who are not aware that they have a family history.  For this reason, individuals with seemingly sporadic cavernous malformations may also benefit from genetic counseling and testing. Visit the Center for Neurogenetics for more information.

Cavernous malformations are complicated conditions, and should be treated at major medical centers by experts in cerebrovascular disorders. Use our online form to request an appointment for a consultation or second opinion.

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Reviewed by Philip Stieg, PhD, MD
Last reviewed/last updated: October 2023
Illustration by Thom Graves, CMI

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