What Is a Cavernoma?
A cavernoma is a formation made up of abnormal, dilated capillaries containing slow-flowing blood, often likened to a mulberry. It can occur in any part of the brain, in the spinal cord and in the brainstem. Unlike high-pressure, high-flow vascular diseases such as a brain aneurysm or an arteriovenous malformation (AVM), a cavernoma is a low-pressure structure; for this reason, when it bleeds, it usually bleeds in a more limited and slower way. Most cases are a single lesion of unknown cause; in familial (inherited) forms there may be multiple cavernomas, and in this situation assessment of the family may come into question. The gold standard of diagnosis is MRI; special MRI sequences that show blood products (gradient echo / SWI) in particular reveal even small cavernomas.
Symptoms and Natural History
A significant proportion of cavernomas never cause any symptoms throughout life and are found only incidentally. When they do cause symptoms, the most common picture is seizures, seen in cavernomas located near the cortex of the brain. The second common situation is bleeding; a cavernoma bleed is mostly small and limited, but in critical regions such as the brainstem even a small bleed can lead to marked neurological symptoms. A cavernoma that has bled once has a higher tendency to bleed again than one that has never bled; for this reason the history of bleeding is one of the most important factors in the treatment decision. The location and size of the cavernoma also affect its course: a small cavernoma in a silent area and one in the brainstem are managed very differently.
Observation or Surgery?
In cavernoma the treatment decision is made individually according to the location of the lesion, whether it causes symptoms, and the history of bleeding. Observation (wait-and-scan): for incidentally found, asymptomatic cavernomas in deep or risky regions, follow-up with interval MRI is generally an appropriate option. Microsurgery (removal): for cavernomas located in an accessible region, causing recurrent bleeding or leading to drug-resistant seizures, surgical removal of the lesion is considered; when it is removed completely, the risk of bleeding from that lesion disappears. For cavernomas in critical regions such as the brainstem the decision is far more cautious, and surgery is considered only for recurrent, symptomatic bleeds. An important note: unlike an aneurysm or AVM, a cavernoma is not suitable for treatments performed from within the vessel (endovascular).
The Surgical Process and Recovery
When surgery is chosen, the aim is to remove the cavernoma as a whole with the least damage to the surrounding healthy brain tissue. The operation is performed under general anaesthesia, under the microscope and, when needed, with neuronavigation and functional mapping; neuromonitoring is used especially for lesions near functional areas or the brainstem. Lesions near the surface are usually easier to reach, while deep lesions require careful surgical planning. The procedure can take a few hours depending on the location of the lesion; it is usually followed by a short period of intensive care and a hospital stay of a few days. In patients operated on for seizures, antiseizure medications are continued for a time and assessed under the neurologist's supervision. A control MRI confirms whether the lesion has been completely removed.
Risks and Realistic Expectations
Although a cavernoma is a benign structure, the decision for surgery requires an honest discussion of risk. The main risk is that, depending on the location of the lesion, the surrounding functional tissue is affected during removal, with consequent temporary or permanent neurological symptoms; this risk is higher especially in the brainstem and functional areas. For this reason unnecessary surgery is avoided in silent, asymptomatic cavernomas. When the lesion is removed completely, the risk of rebleeding from that cavernoma disappears; however, in familial forms follow-up continues because other cavernomas may develop. The effect of surgery on seizures depends on the duration of the seizures and the lesion-brain relationship and cannot be guaranteed. The most suitable approach for you is shared openly, with realistic expectations, according to the location of the lesion, the history of bleeding and your symptoms.