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Cavernous Malformations of the Brain (Cavernomas)
What is a Cavernoma?
A cavernoma or cavernous malformation is a vascular abnormality of the central
nervous system. It consists of a cluster of abnormal, dilated vessels.
Pathologically, it is red to purple in colour, appearing as a raspberry.
Cavernomas contain blood products at various stages of evolution and are usually
less than 3 centimetres in size.
What are the Causes of Cavernous Malformations?
Some individuals are born with a tendency to develop cavernous malformations.
They are not a cancer, which means they cannot spread to other parts of the
body. Occasionally, people can have multiple cavernomas.
Who Gets a Cavernous Malformation?
Cavernous malformations occur in people of all races and sexes. The male-female
ratio is about equal. Family history may be positive especially in patients of
Hispanic descent. Recent work has linked the predisposition to cavernous
malformation to the seventh human chromosome. Cavernomas can be found in any
region of the brain, be of varying size, and present with varying clinical
disorders. In a general population of 1,000,000 - .5% or 5000 people may be
found to have a cavernous malformation, although many are not symptomatic.
What are the Symptoms of a Cavernous Malformation?
Progessive or transient neurologic deficits
It is important to know that a cavernous malformation can be present and not
produce any symptoms. In fact, approximately 12% of patients at our clinic are
Headaches and Cavernous Malformations:
Headaches accompany a cavernous malformation in many patients and may have even
precipitated the diagnostic evaluation uncovering the lesion. 6-10% of patients
with a cavernoma will report headaches as an accompanying symptom.
Progressive or Transient Neurologic Deficits:
Patients may present with double vision, unsteadiness, sensory disturbances, and
weakness or paralysis on one side of the body. These complaints are closely
related to where the lesion is located. 20% of patients will complain of these
when they present to the physician.
Seizures and Cavernous Malformations:
Sometimes patients present to emergency with a seizure and upon investigation of
the seizure a cavernous malformation is found. 36% of patients with a cavernous
malformation will present with seizures.
Bleeding from a Cavernous Malformation:
Up to 25% of patients will present with a hemorrhage. This is the most serious
complication of a cavernoma. If the cavernoma does bleed, it usually, but not
always, starts with a headache. The headache starts suddenly and may be followed
by nausea, neurological problems or a decreasing level of consciousness.
Sometimes a bleed may be very small and produce very mild or no symptoms at all.
Why do Cavernous Malformations Bleed?
We do not know of any specific activity that provokes hemorrhage. We do not
recommend any restriction for our patients.
What is the Risk that a Cavernous Malformation will Bleed?
The risk depends on where the malformation is located. Deep lesions in the
brainstem bleed and cause problems at a rate of 10% per year, whereas
symptomatic hemorrhage from a superficial lesion is very uncommon. The risk with
a superficial lesion is much lower (less than 1% year).
Diagnosis of Cavernous Malformations:
There are two main tests that are used to diagnose cavernomas. These are:
Computerized Axial Tomography (CAT Scan)
Magnetic Resonance Imaging (MRI)
MRI has provided the ability to image and localize otherwise hidden lesions of
the brain and provide accuracy of diagnosis preoperatively. Both the MRI and CAT
scans produce images of slices through the brain. These tests help the doctors
to see exactly where the cavernoma is located. Cavernomas cannot be seen on a
The following are indications to consider treatment of a cavernous malformation:
An episode of bleeding
Treatment of Cavernous Malformations:
There are two possible options available for patients who are found to have a
NOTE: Alternatives may exist to these two options, that your doctor will be
happy to discuss with you.
* The statistics for the above information were based on data obtained by the
University of Toronto Brain Vascular Malformation Study Group and published in
the paper Cerebral Cavernous Malformations: Natural History and Prognosis After
Clinical Determination With or Without Hemorrhage by Philip J. Porter, MD,
Robert A. Willinsky, MD, FRCSC, William Harper, MD and M. Christopher Wallace,
MD, FRCSC. Accepted for publication, J. Neurosurgery, 1997.