What is a cavernous angioma (also called "cavernoma," "cavernous hemangioma," or "occult vascular malformation")?

A cavernous angioma is one of the types of malformations of the blood vessels in the brain that occurs relatively frequently in children. In this condition, small, mulberry-like dilated blood vessels aggregate into rounded masses within the substance of the brain itself or its coverings. These blood vessel malformations obtain their blood supply from very small low-flow blood vessels in the brain, as opposed to certain high flow arterial arteriovenous malformations ("AVMs"), which have large amounts of rapid blood flow coursing through them. Cavernous angiomas can range in size from that of a dime to 3-5 inches or greater in diameter. They appear to be congenital - that is, a patient is born with them - although there are several instances where their development over time has been carefully documented by serial MRI scans. Lesions that are microscopically similar to cavernous angiomas can occur years following radiation therapy to the brain for the treatment of leukemia or tumors of the brain, implying that some type of injury to blood vessels may lead to the development of these malformations in susceptible individuals.

How do cavernous angiomas cause symptoms and how are they diagnosed?

In a series of 55 patients treated by one neurosurgeon here at the Children's Hospital from January 1988 through December 2001, the most common presentation was gradual or rapid onset of a neurologic deficit of some type such as weakness or sensation changes in an arm or leg. Another third of the patients presented with seizures, and another third with headaches, irritability or changes in personality. The symptoms are caused by the pressure of an accumulation of blood in and around the cavernous angiomas when they spontaneously bleed. The pressure of the blood on functioning brain tissue adjacent to the cavernous angioma results in the neurologic deficit or headache. The bleeding from such a blood vessel malformation can be slow and intermittent ("subacute") or it can be rapid, causing a sudden onset of symptoms. MRI scans diagnose most of these lesions. They can be seen on standard CT scans as rounded areas that appear to have a slightly higher density than the rest of the brain. On MRI scanning, however, they often have a very typical appearance, with some of the scan images showing roughly circular, lobulated masses with areas of old and recent hemorrhage within and around the malformation. The cavernous angioma can usually be distinguished from other blood vessel malformations in the brain with some reliability by the radiologist. An arteriogram (a test where dye is injected directly into the arteries that supply the brain and x-ray pictures taken) is typically used to diagnose an AVM; cavernous angiomas, however, are rarely seen on arteriograms because the blood flow within them is very slow and only very tiny blood vessels supply the malformation.

My child has been diagnosed as having a cavernous angioma; what are the possibilities that other children in our family have the same condition?

In our series, there was a strong family history in about 25 percent of our patients. The likelihood that cavernous malformations will be found in other family members goes up if there is a history in other family members of hemorrhages within the brain occurring at an early age, if multiple members of a family have a seizure disorder, or in rare cases if there are associated blood vessel abnormalities on the skin. If a child has multiple cavernous angiomas seen on an MRI of the brain, a phenomenon that can occur in about 25 percent with children with this condition, the likelihood of a positive family history also is higher than normal.

My child has had a hemorrhage into the brain from a cavernous malformation; should the malformation be surgically removed?

Surgery for a cavernous malformation is relatively easy for the neurosurgeon since these malformations can usually be separated from the surrounding brain and since bleeding from the malformations is relatively easy to manage during the operation. If the lesions are small or deep within the brain, they can often be accurately located by computerized guidance techniques that are becoming commonly available in most modern neurosurgical operating room suites. Not all cavernous malformations that become symptomatic can or should be operated upon, however. Our rule regarding their removal is that a single lesion that becomes symptomatic should be removed if it is easily accessible to the surgeon, if it is located in an area of the brain where the surgery itself will not cause or provoke neurologic deficits and if the lesion can clearly be identified as the cause of the patient's symptoms. If multiple cavernous angiomas are detected in the course of an evaluation, the decision regarding surgical excision becomes more difficult unless it can be determined which lesion is responsible for the development of the symptoms from which the patient may be suffering. A course of observation and re-evaluation if symptoms recur sometimes is the safest policy to undertake in this situation.

My child has a cavernous angioma in the brain stem and has recovered from an initially severe neurologic deficit; do you recommend surgery?

The answer to this question very much depends of the location of the lesion within the brain stem, whether it is at the surface of the brain stem in an easily approachable surgical pathway and whether the surgery will provoke additional neurologic deficits. Although the plane of separation around cavernous malformations is often quite clear, following hemorrhage there can be scarring around the margins of the lesion, which can make its separation from normal tissues quite difficult. This problem is particularly relevant in surgery in the brain stem where even the slightest injury to normal surrounding brain tissue may result in permanent neurological deficits that were not present before the operation. There is a great deal of controversy in the medical literature on this topic. In general, we recommend surgery for brain stem cavernous angiomas only when the malformations are superficial in the brain stem and safely approachable through a standard neurosurgical operation. We will recommend surgery for deeper lesions that bleed repeatedly or which cause chronic symptoms that do not improve with time - cases in which we feel that the risks of surgery are outweighed by its benefits.

What is the re-bleeding rate of cavernous angiomas, and can the bleeding be fatal?

There is a great deal of dispute in the medical literature regarding this question. Although a defined rebleeding rate has been described by several workers in this field, it is our experience that the rebleeding rate of cavernous angiomas is extremely variable from patient-to-patient. We have had the opportunity to follow several patients with malformations who have had one episode of bleeding and who have never had a recurrence of their symptoms, even after periods of more than 10 years of follow-up. Often we will suggest that treatment for a very deep and risky-to-treat lesion be withheld until the natural history of the patient's own vascular malformation becomes clarified. Although bleeding from cavernous malformations can cause serious neurologic deficits, in most cases these deficits recover over time and the hemorrhages are rarely fatal, unless the lesion itself is located in a critical area and there are frequent, repeated hemorrhages. Obviously, the answer to this question must be individualized and varies from patient to patient.

One of the physicians we have consulted has suggested stereotactic radiosurgery, gamma-knife, or similar radiation therapy treatment for my child's cavernous malformation. Will this treatment be effective?

This is an another area of controversy in the literature. The group from Pittsburgh, for example, feels that radiosurgery is effective and leads to obliteration of the malformation or to a reduced rebleeding rate over time. Our experience has been that such radiation is poorly tolerated by most patients with cavernous angiomas. The brain appears to swell in the radiated area leading to the production of new neurologic deficits which develop months following the treatment and which require long-term steroid treatment to control. We have had to operate on several patients who have undergone stereotactic radiosurgery or similar treatment for their cavernous angioma because neurologic symptoms persisted and worsened months following treatment. We found in each case that even years following treatment, the malformation was not completely obliterated. Each patient's symptoms dramatically subsided following removal of the malformation and we have therefore recommended stereotactic radiosurgery for these lesions only as a last resort when they are completely untreatable by any other technique and symptoms become intractable.

What makes a cavernous angioma bleed? One has been diagnosed in my child - does his activity need to be restricted?

No one knows what makes the bleeding from these malformations occur. Rarely does a sudden bleeding event seem clearly related to a specific activity. We have seen bleeding present after episodes of head trauma, but many children with multiple cavernous angiomas in their brains lead normal, active lives. It makes sense, however, to avoid activities where the likelihood of severe head trauma is high - such as organized football, etc.

If you have any questions, please contact us for more information.