Cavernous malformations (cavernomas or cavernous haemangiomas) are abnormal collections of veins which develop in the brain usually before birth.
These are often no symptoms for cavernomas, and not all of them need treatment. Occasionally cavernomas bleed, and if they do they can cause a stroke. Sometimes, seizures can occur.
If cavernomas bleed repeatedly or cause seizures surgery may be recommended. The surgical removal of cavernomas usually results in a cure, however the process does carry risks. The risks are higher if the cavernoma is in the brainstem, or in other deep or critical areas of the brain.