Incidental and Asymptomatic Cavernous Malformation

Sometimes a cavernous malformation lesion (cavernous angioma, cavernoma) is found on MRI when doctors are investigating a separate condition. Sometimes familial cavernous malformation (CCM) is diagnosed through imaging or genetic testing because of family history rather than symptoms.

An incidental or asymptomatic cavernous malformation (CCM) diagnosis can lead to significant anxiety. You may wonder whether you are destined to have a hemorrhage or other bad outcome. Here is the bottom line: if your cavernous malformation was found without symptoms or previous hemorrhage, you are more likely to remain hemorrhage-free than you are to have a bleed.

More specifically, people who were diagnosed incidentally (while doctors were investigating another condition) were followed by researchers at the Mayo Clinic.  They found that the risk of subsequent hemorrhage was exceptionally low at 0.08% per patient-year.

A separate study explored the prevalence of symptoms (not just hemorrhage) in those with a familial CCM1 diagnosis. It is believed that only half of those who test positive for a CCM1 mutation will ever develop significant symptoms of the illness. The same is likely true of those with CCM2 mutations. CCM3 tends to be more aggressive and there are proportionally fewer asymptomatic patients.

If you have a familial diagnosis, it is wise to have an occasional follow-up doctor’s visit to maintain a relationship with a care provider should you ever develop symptoms. For a solitary incidental cavernous malformation, ongoing care should be discussed with your diagnosing doctor. If the lesion is in an area of the brain known to be more prone to hemorrhage such as the brainstem, it may be wise to maintain a care provider relationship. For others, the decision may be based on comfort level. Surgery is never recommended for an asymptomatic cavernous malformation that has not hemorrhaged.  Please refer your care provider to the Alliance to Cure Cavernous Malformation peer-reviewed Clinical Care Consensus Guidelines for more information on clinical decision-making.

Moore SA, Brown RD, Jr., Christianson TJ, Flemming KD. Long-term natural history of incidentally discovered cavernous malformations in a single-center cohort. J Neurosurg. 2014;120(5):1188-1192.

Fischer A, Zalvide J, Faurobert E, Albiges-Rizo C, Tournier-Lasserve E. Cerebral cavernous malformations: from CCM genes to endothelial cell homeostasis. Trends Mol Med. 2013;19(5):302-308.


Updated 4.16.2022