Broadly speaking, brain lesions consist of certain types of damage to the tissues of the brain. Trauma to the head, certain health conditions, and tumors (malignant or benign) are all considered brain lesions.
The causes of brain lesions vary from person to person. Some are caused by trauma, such as following a car accident. Others may be congenital. The symptoms of brain lesions vary depending on the cause as well as the exact location of the lesion within the brain.
We have outlined several different types of brain lesions below. Ask your doctor if you have any questions about brain lesions or would like further information about a specific type.
Arteriovenous Malformations (AVMs) are tangled webs of veins within the brain that may have unusual connections between arteries and veins. Blood does not travel through the typical pathways between veins and tissue. When tissue does not receive enough oxygenated blood, the tissue and surrounding nerves may become damaged or die altogether.
AVMs can grow larger over time. Not all AVMs cause symptoms.
Some AVMs can leak blood into the brain, causing intracranial hemorrhage, although these hemorrhages are very small and do not cause significant damage.
Tumors are abnormal growths of cells that can form anywhere in the body. Brain tumors occur within the tissues of the brain. Tumors are most commonly associated with cancer; however, they are not always cancerous.
Malignant (cancerous) brain tumors may spread to surrounding tissue or metastasize to other parts of the body. Benign (non-cancerous) brain tumors generally stay localized, but may disrupt normal brain function depending on their size and rate of growth.
Cerebral cavernous angiomas (CCAs) are tightly packed, thin-walled blood vessels that are most often found in the brain and spinal cord. The blood which passes through CCAs is often stagnant or slow moving, which can become clotted and lead to neurological issues.
CCAs do not always cause symptoms. They may not become apparent until they begin to bleed.
An aneurism is weakness in the wall of a blood vessel. When an aneurysm is present in the brain, it is known as a cerebral aneurism.
In some cases, the weak portion of the vessel is pushed outwards, and may resemble a berry on a vine. This is known as a saccular, or berry, aneurysm.
Many brain aneurysms never rupture, and may be detected during another medical scan. Treatment may never be necessary for these aneurysms.
When aneurysms do rupture or leak within the brain, they lead to hemorrhagic stroke and can quickly become life-threatening. Aneurysms that have previously bled are at higher risk to do so again in the future.