Cavernous malformations are clusters of abnormal, tiny blood
vessels, and larger, stretched-out, thin-walled blood vessels filled
with blood in the brain. These blood vessel malformations can also occur
in the spinal cord, the covering of the brain (dura), or the nerves of
the skull. Cavernous malformations range in size from less than
one-quarter inch to 3-4 inches. Cavernous malformations are also
referred to as cavernomas, cavernous angiomas, cavernous hemangiomas or
intracranial vascular malformations. The term angioma implies a
propensity for growth that is associated primarily with the familial
form of the illness.
Incidence and Prevalence
- The incidence of cavernous malformation is estimated at one in
- Cavernous malformations account for an estimated 8-15 percent
of all intracranial and spinal vascular malformations.
- A minimum of 30 percent of people with cavernous malformations
will develop symptoms, most in their 20s or 30s.
- Cavernous malformations hemorrhage at an estimated rate of
approximately 0.7-1.7 percent per lesion each year.
- At least 20 percent of those with cavernous malformation have
the familial form of the illness (referred to as cavernous angioma). The
familial form is associated with Hispanic heritage, multiplicity of
lesions and a demonstrated propensity for growth of lesions. The latter
two features are less characteristic of the sporadic form of the
- If a parent has familial cavernous angioma, his or her child
may have a 50 percent chance of developing this condition.
- As high as 40 percent of solitary cavernous malformations may
have an associated venous malformation.
- Diagnosis by age: age 20 and younger: 25-30 percent; age
20-40: 60 percent; age 40 and older: 10-15 percent.
A person with a cavernous malformation may experience no
symptoms. When symptoms occur, they often are related to the location of
the malformation and the strength of the malformation walls. The type
of neurological deficit is associated with the area of the brain or
spinal cord that the cavernous malformation affects. Symptoms may appear
and subside as the cavernous malformation changes in size due to
bleeding and reabsorption of blood. Any of the following symptoms may
- Weakness in arms or legs
- Vision problems
- Balance problems
- Memory and attention problems
Cavernous malformations are part of a group of lesions known as
"angiographically occult vascular malformations." This means that they
are not visible on an angiogram. Angiograms cannot visualize cavernous
malformations because blood flows through these types of lesions slowly.
The relatively milder symptoms from the lesion, even when ruptured, are
presumed to be related to this state of relatively low blood flow.
Magnetic resonance imaging (MRI), with and without contrast and
with gradient echo sequences remains the best means of diagnosing
cavernous malformations. MRI scans may need to be repeated to analyze a
change in the size of a cavernous malformation, recent bleeding, or the
appearance of new lesions.
In general, lesions that are and incidentally discovered should
be followed with MRI scans annually for two years, then every five years
thereafter. An MRI should be performed sooner if there is any clinical
evidence of hemorrhage or new symptoms appear. Some patients may be
prescribed anti-convulsant medications. This is an example of a subtype
of AVM that may be monitored radiographically, specifically because the
consequences of hemorrhage from these lesions are much less dire than
those from classic AVMs or aneurysms.
Surgery should be considered for seizure control if: 1. Seizures
cannot be controlled through medication management; 2. The cavernous
malformation is in a low risk, easily accessible area of the brain; and
3. It has been determined that the lesion is causing the seizures. If
seizures are controlled through medication management, there may not be
any compelling reason to perform surgery. In general, although seizures
may indeed be cured by successful microsurgical removal, the primary
goal of surgery is to prevent future bleeding and problems such as
seizures that may be associated with it. Seizure control by itself is
not justification for performing microsurgery on a cavernous
Surgery may be indicated in patients who have experienced one
neurologically symptomatic hemorrhage from a lesion in a low risk,
easily accessible area. For lesions in eloquent areas of the brain,
surgical removal should be contemplated in the context of surgical risk
to nearby brain tissue, balancing this risk against the risk of bleeding
to that same tissue in the event of a second hemorrhage.
Surgical removal should be considered in patients with
progressive neurological deficits, but such neurological deficits can
worsen after surgery. Although brain or spine surgery may carry
substantial risk, so may hemorrhage into nervous tissue. The risk of
surgery must be balanced against the risk of no surgery, on an
individualized, case-by-case basis.
Most patients can leave the hospital a few days following surgery
and resume normal life within a few weeks of surgery. Many patients can
be cured without neurological deficit. Many patients with neurological
deficits are able to regain their neurological baseline (condition at
time of surgery) with therapy, and may even show further improvements.
Patients with neurological deficits may require a prolonged period of
rehabilitation. The rebleeding rate of cavernous malformations is
extremely variable. Some patients with malformations and one bleeding
episode never experience a recurrence of their symptoms, while others
experience frequent rebleeding.
Cavernous Malformation Resources