1. What is a Cavernous Angioma ?
Cavernous Angiomas (CA); also known as cavernous hemangiomas, cavernous malformations, or cavernomas; are well circumscribed, benign vascular lesions composed of thin walled irregular sinusoidal caverns without intervening neurological tissue. These lesions differ from arteriovenous malformations in that they do not have large feeding arteries or large draining veins, and their endothelium lining is without the typical elastica or smooth muscle. The vessel walls of the cavernous angiomas may hemorrhage, thrombose, or calcify. Occasionally, one may present with multiple lesions. Cavernous Angiomas comprise 10-15% of both intracranial and spinal malformations and are present in 0.3-0.5% of a large autopsy series.
2. What causes Cavernous Angiomas?
It is felt that these lesions are probably congenital although they may not appear on imaging studies until adulthood after they have had time to become larger. Enlargement is most commonly a result of small asymptomatic hemorrhages inside the malformation.
Genetic factors may also play a role. In the southwest, there appear to be some Hispanic families with many family members who are affected with multiple cavernomas. The USC Department of Neurosurgery and many of its patients were involved in a study that identified the gene that is associated with familial cavernous angiomas.
3. How do Cavernous Angiomas typically present? What are the signs and symptoms of Cavernomas?
Typically these lesions present with hemorrhage, seizure, focal neurological deficit, or incidentally.
It is estimated that the Cavernous Angioma hemorrhage rate is approximately 0.7-1.7% per lesion per year. Most of these hemorrhages are very small, usually inside the caverns, and may not even produce symptoms. Massive hemorrhages are distinctly uncommon, but hemorrhages outside the malformation (extranidal hemorrhages) are the ones that cause damage.
It is uncommon to be left with a permanent neurological deficit from a hemorrhage from a Cavernous Angioma unless the lesion is located in the brain stem.
If a Cavernous Angioma causes more than one symptomatic hemorrhage, the likelihood of further hemorrhage in the following year is higher. In the circumstance of two or more symptomatic hemorrhages in close succession, treatment is highly recommended.
Cavernous Angiomass located in the cerebral cortex may cause irritation of the cortex thereby inducing a seizure. Patients whose Cavernoma presents with a seizure, must be given anti-convulsant medications.
Focal neurological deficits such as muscle weakness, numbness, double vision, or speech difficulties may also be an indication that one may have a Cavernous Angioma. The specific deficit will depend on the exact location of the lesion.
Commonly, Cavernous Angiomas are discovered incidentally (without any neurological signs or symptoms).
4. How is a Cavernous Angioma diagnosed?
Cavernous Angiomas are diagnosed by MRI scans and are best seen on the T2 weighted images. Large Cavernomas may be seen on CT scans although this is not the recommended image selection. Small Cavernous Angiomas will most always be missed on CT and very small lesions can even be missed on MRI.
Cerebral angiograms do not demonstrate Cavernous Angiomas since they are not made up of arteries and veins like arteriovenous malformations (AVM) are.
5. I’ve been told I have a Cavernous Angioma. What is my next step?
There are many factors that determine whether or not the lesion should be treated.
A. Asymptomatic-incidentallly discovered lesion
In general, lesions that are asymptomatic and incidentally discovered are typically followed with MRI scans yearly for 2 years, then every 5 years thereafter. An MRI should be performed sooner if there is any clinical evidence of hemorrhage or new symptoms. Your physician may or may not decide to give you on anti-convulsant medications.
B. Symptomatic lesions
(i) Seizure – It is important to achieve complete seizure control with medication. If your seizures are intractable (unable to control with multiple medications), your Cavernous Angioma is in a low risk, easily accessible area of the brain, and your neurologist has performed studies that indicated the lesion is causing the seizure, surgery for resection of the lesion may be indicated. If your seizures are controlled with medication, there may not be a compelling reason to have surgery. Epilepsy alone is not and indication for surgical resection unless the above is true.
(ii) Hemorrhage – If you have experienced one clinically relevant (neurologically symptomatic) hemorrhage, and your lesion is in a low risk, easily accessible area, surgical removal may be indicated. For lesions in eloquent areas of the brain, surgical removal should be contemplated following the second clinically relevant hemorrhage. We have found that those patients who had a second clinically relevant hemorrhage were more likely to have a third hemorrhage, and the neurological deficit related to the third hemorrhage was much more significant compared to that following the first hemorrhage.
(iii) Progressive neurological deficit – Surgical removal is probably indicated as long as you understand that your specific neurological deficits will most likely be worse after surgery. Chances are good that with time and therapy you will return to your neurological baseline (condition at time of surgery), and may even improve further. Always remember that there are no guarantees.
6. What are the risks and complications of surgery?
The risks of surgery depend on a number of factors including preexisting brain damage from the lesion’s presence, prior hemorrhages, location and size of the lesion, and health of the patient.
Because these lesions can be difficult to completely remove, there is a chance that you may have residual lesion after surgery. Because of the experience of USC’s vascular neurosurgical team, our success rate for complete surgical resection is excellent. Only teams that specialize in this type of surgery can be expected to attain such results.
7. Are there alternatives to surgery?
Stereotactic Radiosurgery using Gamma Knife, Linac, and other modalities have been used in an attempt to treat Cavernous Angiomas without surgery. Unfortunately the results of such treatment have been very disappointing. The malformations do not go away. Further there has been an unusually high incidence of brain swelling after Radiosurgical treatment for some Cavernous Angiomas. We at USC think that this might be due to the accidental blockage of veins that can be associated with Cavernous Angiomas. These veins are called Venous Angioma, are not pathological or dangerous n and of themselves, but are important for normal brain blood circulation. Therefore they must not be blocked or damaged. It is possible that in some instances Radiosurgery might have blocked these resulting in brain swelling.
7. It is a difficult decision. Who can I talk to?
It is possible that your surgeon can give you the names of people who have had to make a similar decision and who would be willing to talk to you regarding their experiences.