Observation of Cavernous Malformation

A “watch-and-wait” approach to any medical condition can be stressful and emotionally draining. But in many cases of cavernous malformations, simply monitoring the condition over time is a reasonable option. With increasing use of imaging technologies, an incidental, or unexpected, cavernous malformation finding is becoming more common. However, if it’s not causing problems, treatment may not be necessary.

The first step in determining whether observation is the right treatment path for you is to understand the natural course of a cavernous malformation and the potential risks and benefits of all possible treatment options. In this article, we discuss these considerations and describe what observation will entail. 

Cavernous malformations are clusters of abnormally dilated blood vessels that can form in the brain or spinal cord. They range in size from a few millimeters to several centimeters (about 0.5 to 2 inches). Although most cavernous malformations do not cause any symptoms and may not need to be treated, some can produce neurological symptoms such as headaches, seizures, and changes in motor function (your ability to control body movements). 

Cavernous malformations are caused by genetic mutations. In most cases, these mutations occur randomly in healthy individuals and are called sporadic cavernous malformations. In other cases, the mutations are inherited from a parent and are called familial cavernous malformations. The familial form is particularly associated with mutations in the KRIT1, CCM2, or PDCD10 genes. An individual with familial cavernous malformations may develop multiple cavernous malformations throughout their lifetime.

Although the exact cause for these genetic mutations is unknown, exposure to ionizing radiation, particularly when given at high doses, has been reported to cause cavernous malformations in several cases.

The treatment of a cavernous malformation depends on the location of the lesion, the size and number of lesions, and the presence or severity of symptoms. Doctors create treatment plans for patients based on several factors, including:

• Risk of bleeding: Cavernous malformations have abnormal vessel walls and are prone to oozing. The presence of blood can irritate the surrounding brain tissues and cause symptoms such as seizures. If a cavernous malformation ruptures, the enlarging pool of blood may compress the surrounding brain and further worsen symptoms.
• Presence of symptoms: In patients with severe symptoms, treatment may provide long-awaited relief. However, for patients without symptoms and at low risk of future symptoms, treatment may only add unnecessary risks and financial burden.
• Location of the cavernous malformation: Cavernous malformations located in deep regions or neighboring critical tissues of the brain are less surgically accessible and riskier to remove.
• Patient preference: For some patients without symptoms or with mild symptoms, treatment may be preferred for peace of mind or to avoid the financial burden of regular follow-up imaging and appointments.

Treatment options include observation or surgical resection (removal). In 2017, the Angioma Alliance scientific advisory board released treatment guidelines based on the existing research. These consider the factors described above when deciding which treatment option would be beneficial. Have a thorough discussion with your neurosurgeon to determine which treatment option will be right for you.

Observation is a very reasonable option for patients with cavernous malformations with no symptoms or mild symptoms, especially if safe surgical removal is difficult because of the location of the cavernous malformation, or if you have other medical conditions that make surgery too risky. 

There are several benefits to the “watch-and-wait” approach for a cavernous malformation. With observation, you can avoid costs and potential complications associated with surgery.

On the other hand, no active treatment means that there will always be a risk of bleeding from the cavernous malformation. Blood can irritate nearby brain tissues causing seizures or other neurological problems such as weakness. The annual bleeding rate can range from 1% to 5% per year, but in patients without symptoms or previous history of a cavernous malformation bleed, this risk is less than 1% per year.

Observation of a cavernous malformation will involve regular imaging scans to check for any bleeding. Magnetic resonance imaging (MRI) scans are often recommended for cavernous malformations located in the brain because they provide highly detailed visual information. Imaging may be performed annually for the first few years, then repeated at regular intervals or as needed after discussion with your neurosurgeon.

The abnormal vessels involved in a cavernous malformation do not simply go away or disappear; however, blood clots that form within and surrounding a cavernous malformation can be reabsorbed and cause the cavernous malformation to shrink. In some cases, the cavernous malformation can shrink so much that it becomes barely noticeable on an imaging test.

Observation of a cavernous malformation is a favorable treatment option for patients experiencing no symptoms. The risk of bleeding is low, especially if the cavernous malformation has never bled before. With regular monitoring, the cost and potential complications of other treatment options such as surgery can be avoided.

• Alliance to Cure Cavernous Malformation
• American Association of Neurological Surgeons
• National Organization for Rare Disorders