Superficial cavernomas are considered to be those occurring in the brain but not in the brainstem (midbrain, pons or medulla), cerebellar nuclei, thalamus or basal ganglia. A typical MRI appearance can be seen in the adjacent image.
What are the chances of recovery from a bleeding superficial cavernoma?
It is very unusual for superficial cavernomas to produce bleeding that leads to permanent deficits. Although they can cause a stroke, the bleeding is usually not under a great enough pressure to destroy a large volume of brain. However, the more common long-term consequence of small bleeding is the accumulation of iron (after the breakdown of red blood cells) in the surrounding brain leading to epilepsy. It is more often epilepsy rather than stroke that leads to long-term problems. It is in this zone that the nerve cells sometimes develop firing that is independent to their function and if this firing can recruit other connected nerve cells an epileptic attack (or a seizure) occurs.
What are the chances of a superficial cavernoma causing epilepsy?
It is not possible to know how often cavernomas lead to epilepsy. For superficial cavernomas it is the most common way that cavernomas are discovered. Once several seizures have occurred it is likely that long-term anticonvulsant medications and/or surgical excision of the cavernoma will be required to control the epilepsy.
How are superficial cavernomas treated?
Watch and wait.
The majority of superficial cavernomas can be managed without the need for surgery. If anticonvulsants are needed to control epilepsy many can tolerate the long-term use of these medications. However, anyone on anticonvulsants needs to be aware of the potential side effects of the medications as well as other factors that might interfere with their efficacy.
Microsurgery is the only proven effective treatment for the removal of cavernomas. It involves removing a part of the skull overlying the cavernoma (to be replaced at the end of surgery) and computerised guidance to where the cavernoma is located. This is often done with a minimally invasive technique. When this has been found, with the aid of a microscope for vision, the cavernoma is separated and then removed from the surrounding brain tissue. The surgery has a very low risk of death or permanent new deficits. The risk for this is usually less than 2% but needs to be individualised according to location. The result of surgery in the control of epilepsy and cure of the risk of further bleeding from the cavernoma is excellent. The reason for the ability to control the epilepsy is that the altered brain immediately around the cavernoma can usually be safely removed. However, occasionally (in about 20% of cases) epilepsy is failed to be controlled with surgery and this can be due to leaving the epileptic focus behind at surgery (remembering it is not the lesion itself that is the site for the epilepsy but rather surrounding brain), because the epileptic focus has moved to a remote site by the process of kindling (a process by which a remote site of nerve cells under a constant bombardment of signals from the original focus becomes an independent source for the epilepsy), or that the epilepsy has nothing to do with the cavernoma. It is sometimes possible to know where in the brain the seizure starts but this is not always the case.