Cavernous Malformations: A Comprehensive Guide
What Is a Cavernous Malformation?
Cavernous malformations are a type of vascular malformation, which are abnormalities in the blood vessels of the brain, characterized by an abnormal cluster of blood vessels that look like a raspberry. The walls of these blood vessels are abnormally leaky and therefore prone to repeated bleeding. Cavernous malformations are also sometimes referred to as cavernomas, cavernous angiomas, cavernous hemangioma, or cavernous vascular malformation.
Cavernous malformations are rare, with an incidence of 0.3% to 0.5% in the general population (1 in every 200 to 250 people). They are not usually caused by injury or trauma. They can be either sporadic or familial/hereditary. Those with sporadic cavernous malformation usually have just one lesion, whereas those with the familial form typically have multiple lesions throughout the brain and spinal cord. If a person has more than 3 cavernous malformations and a family history of seizures, the diagnosis will most likely be the familial form of the condition.
Familial cavernous malformations have been attributed to mutation in 3 genes, KRIT1/CCM1, CCM2, and PDCD10/CCM3. These mutations are passed on in an autosomal dominant fashion, meaning that children will likely inherit the genes. However, symptoms and severity among family members can be very different.
Cavernous malformations can occur anywhere in the central nervous system but are most commonly found in the cerebral hemispheres, in the deeper parts of the brain (such as the brainstem or basal ganglia), and, rarely, in the spinal cord. Symptoms and treatment strategies will vary on the basis of the size and location of the malformation.
We currently have no explanations as to why cavernous malformations occur or even why the related genetic mutations occur. They have been reported to sometimes develop after radiation therapy.
Cavernous Malformation Bleeding
The most serious outcome of a cavernous malformation is bleeding. The leaky walls of these abnormal blood vessels make them prone to hemorrhage. Cavernous malformations are low-flow, low-pressure lesions, and the bleeding is not as heavy as with an arteriovenous malformation, but they still can rarely be life-threatening depending on their location. After a bleed, the iron in the blood irritates the surrounding normal brain tissue leading to symptoms, most commonly seizures.
Cavernous malformations that have previously bled have a 3% to 5% chance of bleeding per year, while for those that have not bled, the chance is 1%. Brainstem cavernous malformations have an annual bleed rate of 3% to 5%. Triggers that cause bleeds have not been identified, but there is some evidence to suggest that there is a minimal increase in the chances of cavernous malformation bleeding during pregnancy. If you plan to start a family or are currently pregnant, you should inform your neurosurgeon.
Symptoms of Cavernous Malformation
Cavernous malformations can cause a wide variety of symptoms depending on their size and location and whether it has already bled. Although most symptoms are caused by bleeding, the pressure applied by a cavernous malformation on the surrounding brain tissue is also a cause. Around 20% of those with sporadic cavernous malformation remain asymptomatic, but for those with a familial form of the disease, that number is 40%. The following are some of the symptoms that you could experience:
- Headaches: Unusually severe and frequent headaches warrant a visit to your doctor. It is important to understand that headaches can be a symptom of numerous conditions; Cavernous malformation is one of them. Your neurosurgeon will help you find the correct diagnosis.
- Seizures: Although the characteristic full-body shaking that is normally thought of with seizures could occur, seizures can also present as episodes of just blanking out with a staring look or experiencing abnormal taste and smell sensations. The chances of developing seizures within 5 years of a cavernous malformation diagnosis is 4% to 6%.
- Neurological deficits: Different parts of the brain control different functions of the body, so the symptoms of a cavernous malformation will vary depending on its location. Neurological deficits can include weakness of limbs, speech difficulties, vision problems, and balance problems.
Diagnosing Cavernous Malformations
Angiography is a test commonly used to diagnose various types of diseases of the brain’s blood vessels. However, cavernous malformations are known as “angiographically occult,” which means that the lesion cannot be seen with angiography.
The most commonly used tests are computed tomography (CT) and magnetic resonance imaging (MRI) scans. CT scans are quicker and less expensive, and they provide information on emergent life-threatening conditions caused by a cavernous malformation, such as bleeds and a build-up of fluid in the brain (hydrocephalus). However, the clarity of CT images is usually not enough to diagnose a cavernous malformation.
MRI is the test of choice for diagnosing a cavernous malformation. On the images, a cavernous malformation will usually have a characteristic “popcorn” appearance. Other associated abnormalities such as developmental venous anomalies can also be detected by MRI.
Depending on your symptoms and specific circumstances, you might be asked to undergo an MRI scan at regular intervals to monitor the cavernous malformation’s size.
Difference Between Cavernous Malformations and Arteriovenous Malformations
Among the many possible blood vessel abnormalities in the brain, arteriovenous malformations are the most common, followed by cavernous malformations. Although their symptoms can be similar, it is important to tell the difference between the two of them so that a correct treatment can be used.
Arteriovenous malformations are abnormal clusters of thick-walled blood vessels, including arteries that bring in blood and veins that drain it back out. They are high-flow high-pressure lesions, so if an arteriovenous malformation ruptures, the bleeding is usually more severe than it is after a cavernous malformation rupture.
Arteriovenous malformations can be detected by MRI, but cerebral angiography is best test for diagnosing them and deciding on the appropriate treatment strategy.
Treatment options for an arteriovenous malformation include watchful observation, medications, endovascular embolization, surgery, and/or stereotactic radiosurgery. The best treatment option will depend on the arteriovenous malformation’s size, location, and bleeding status, as well as the patient’s general health. A neurosurgeon should be consulted to determine the best plan.
|Cavernous Malformation||Arteriovenous Malformation|
|Blood vessel walls||Thin||Thick|
|Bleeding||Less than with an AVM||Profuse|
|Neurological deficits||Less severe than an AVM||Severe|
|Test of choice||MRI||Cerebral angiography, MRI|
The treatment options for cavernous malformations include surgery for definitive removal when indicated and medications to control the seizures. If the cavernous malformation is large or the seizures are not treatable via medications, surgery is indicated.
Being diagnosed with a cavernous malformation can be a difficult and emotional time. Try to connect with a group of friends and family who can support you, and do your best to keep your stress level under control and maintain a healthy lifestyle. Always discuss any concerns with your neurosurgeon, who is the best person to advise you through this trying time.
- Cavernous malformations are abnormal clusters of blood vessels that look like a raspberry.
- One in every 200 to 250 people may have a cavernous malformation.
- Symptoms of cavernous malformations can include headaches, seizures, and neurological deficits.
- MRI is the best test for diagnosing a cavernous malformation; they cannot be seen with cerebral angiography.