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Romanian Neurosurgery Vol. XVI nr. 1

CEREBRAL CAVERNOMA

I. POEATA1, ST.M. IENCEAN2
1Clinical Emergency Hospital “Prof Dr Nicolae Oblu” Iasi, University of Medicine and Pharmacy
“Gr.T. Popa”, Iasi, Romania
2Neurosurgery, Clinical Emergency Hospital “Prof Dr Nicolae Oblu” Iasi, Romania

Cerebral cavernoma can be located in any brain region, be of varying size and present with different clinical disorders. Some
cases are found incidentally. Conservative treatment is recommended if the patient has an asymptomatic lesion or the
malformation is located in a critical brain region but the patient has only minimal symptoms and no history of symptomatic
bleeding or the patient has multiple cavernous malformations and the actual symptomatic lesion could not be determined. The
main indications for surgery are based on reductions or control of seizures, reversal of symptoms or deficits related to mass effect,
and prevention of hemorrhage or recurrent hemorrhage. Generally surgical results are very good.

Keywords: cerebral cavernoma, gamma knife, hemorrhage, surgery

INTRODUCTION
Cerebral cavernoma or cavernous angiomas are

cerebral cavernous malformations and they are
relatively rare lesions, comprising 5 to 13% of the
central nervous system vascular anomalies. After
thrombosed arteriovenous malformations, cavernomas
are the second most common histological subgroups of
angiographically occult cerebrovascular malformations.
With the advent of magnetic resonance imaging (MRI)
there has been a substantial increase in the number of
patients diagnosed with these lesions. Pathological
studies have demonstrated that multiple lesions may
represent more than 25% of the cases. There is no sex
prevalence , although a familial form has been
confirmed by several investigators.

Cavernous angiomas can be located in any brain
region, be of varying size and present with different
clinical disorders.

HISTOPATHOLOGY
Cerebral cavernoma resembles a honeycomb of

irregular blood-filled vascular spaces (caverns). The
vascular walls are thin and consist of a single layer of

flattened endothelial cells. Recent analysis by
transmission electron microscopy show that the thin
walls of cerebral cavernoma lack significant
subendothelial support and contain very few intact tight
junctions between the endothelial cells. These findings
help explain the recurrence of microhemorrhage in
cerebral cavernoma. The vascular spaces of cerebral
cavernomas are separated by a collagenous matrix
devoid of elastic lamina or smooth muscle. Deposits of
calcium are often found in cavernomas, especially
within vascular walls. The lesion is well demarcated
from the surrounding normal tissue by a zone of gliosis.
The absence of intervening neural tissue previously
was recognized as a criterion for diagnosis and a
cardinal feature distinguishing cavernous angioma from
telangiectasia.

Several pathological variations of cerebral
cavernomas can be distinguished and mixed lesions
containing an arteriovenous component or combined
with capillary telangiectases have been reported. Most
cavernomas show evidence of hemorrhage,
microscopic or gross, and many show evidence of

CEREBRAL CAVERNOMA

Romanian Neurosurgery Vol. XVI nr. 1

repeated hemorrhage. Small hemorrhages followed by
organization, fibrosis and calcification probably account for
slow progressive growth of cerebral cavernomas in
patients with long clinical histories.

CLINICAL PRESENTATION
Patients with a cavernous malformations may

present with seizures, hemorrhage or mass lesions.
Some cases are found incidentally. There might be a
correlation between the clinical and radiological
manifestation and the histological type, but there are
not enough data to support this concept. The
propensity of cerebral cavernomas to bleed is well
established. Most of the hemorrhages consist of
intralesional or perilesional “slow ooze” or “cluster of
bleeding sites” and result in subacute or stepwise
worsening of the neurological signs. These bleeding
patterns have been attributed to the low blood pressure
found in this type of malformation. There are no factors
that predict the degree or rapidity of hemorrhage in
individual patients. In many patients multiple
microscopic hemorrhages occur, but are often not
clinically detected. The data regarding the incidence of
bleeding and rebleeding of cavernous malformations
have the most clinical relevance because they affect
the decision regarding surgery. The incidence of
symptomatic hemorrhage of cavernous angiomas in
general is low. The most important risk factor for
subsequent hemorrhage is the occurrence of a prior
hemorrhage. An annual hemorrhage rate of 4.5% was
described for the patients whose first clinical
presentation was hemorrhage.

Several authors proposed that female hormones
are implicated in the pathogenesis of hemorrhage from
an intracranial cavernous angiomas. Higher bleeding
rates from cavernous malformations was found during
pregnancy, particularly in the first trimester, which is
characterized by vascular proliferation of the
endometrium associated with secretion of human
chorionic gonadotropin, progesterone, end estrogens.
The size of cavernous malformations is known to
increase during pregnancy and to decrease after
delivery. The increase in the blood volume occurring

during pregnancy might be an important factor in
angioma rupture as well.

Cavernous malformations of the brain stem account
for between 18 and 22% of all intracranial cavernous
malformations (Yasargil). Clinical malignancy of brain
stem and basal ganglia cavernomas could be related to
the high sensitivity of these areas even to a small
amount of bleeding. The rebleeding rate after a first
hemorrhage in this group was found to be as high as
21% per year per lesion.

The natural history of familial cavernous
malformations is less benign than that of the sporadic
form. The rate of symptomatic hemorrhage was found
to be higher in this group - 6.5% per patient per year
and recently Labauge showed a hemorrhage risk of
2.5% per lesion-year in a study of 40 patients familial
cavernous malformations. Eleven patients (27.5%)
developed new lesions during a mean follow-up of 3.2
years. Development of de novo lesions in familial form
of cerebral cavernous malformations is known and the
clinical features have been described.

RADIOGRAPHIC EVALUATION
Size, location, pathological architecture, degree and

rapidity of hemorrhage within the lesion presumably
determine the neuroradiological appearance and the
clinical course.

CEREBRAL ANGIOGRAPHY
Cerebral angiography is relatively insensitive and is

diagnostic in only 10%. Delayed imaging during the
venous phase and careful subtraction may present the
cavernoma as an avascular region in the capillary
phase or as an avascular mass with displacement of
adjacent vessels.

A dense venous pooling pattern and a localized
area of capillary staining that persists into the late
venous phase have both been described as diagnostic
feature of cavernous malformations.

COMPUTERIZED TOMOGRAPHY
Computerized tomography studies often detect

lesions consistent with cavernous malformations, but

I. POEATA

Romanian Neurosurgery Vol. XVI nr. 1

the CT findings are not specific for this entity. The
lesion commonly appears hyperdense, or mixed
hyperdense and isodense. Mass effect is frequently
present. Faint contrast enhancement has been
described. By CT criteria alone it is often difficult to
differentiate glioma or infarction from a cavernous
angioma. Computerized tomography may occasionally
miss even relatively large lesions.

MRI
The sensitivity of MRI increases the probability of

detecting a cavernous malformation.
T2 - weighted studies are more sensitive than T1 -

weighted images. MRI is also particularly valuable in
terms of specificity. On T2 - weighted images
cavernomas appear as areas of mixed signal intensity
with “reticulated” appearance and a prominent
surrounding rim of decreased signal intensity, thought
to represent hemosiderin. Presence of multiple lesions,
a reticulated core of increased and decreased signal
intensity, a prominent surrounding rim of decreased
signal intensity strongly support the diagnosis of
cavernous malformation.

MANAGEMENT
Management strategy are based on a combination

of factors including the natural history, age of the
patient, location of the lesion, and risk of operative
removal. When dealing with a patient harboring several
lesions or a family affected by the hereditary form of
this condition, an aggressive approach is not always
advisable.

CONSERVATIVE TREATMENT
Conservative treatment is recommended if: the

patient has an asymptomatic lesion;
the malformation is associated with a medically

controlled seizure disorder; the malformation is located
in a critical brain region but the patient has only
minimal; symptoms and no history of symptomatic
bleeding; the patient is elderly or the patient has
multiple cavernous malformations and the actual
symptomatic lesion could not be determined.

SURGERY
The main indications for surgery are based on

reductions or control of seizures, reversal of symptoms
or deficits related to mass effect, and prevention of
hemorrhage or recurrent hemorrhage. Generally
surgical results are very good.

The location of the cavernous malformation is the
most significant factor in determining prognoses. Worse
surgical outcome was associated with lesions located
in the thalamus, basal ganglia, pineal region, brain
stem, and spinal cord and with subtotal resections.
Although the

definitive risk is not known, it appears that thalamic
cavernous angiomas have a significant surgical
complication rate and nonoperative approaches have to
be seriously considered in stable patients. Surgical
excision for a symptomatic brain stem cavernous
angioma is recommended because of the poor ability of
the brain stem to withstand mass expansion from
hemorrhage. For those women with known cavernous
malformations who are considering having children,
surgical intervention may be entertained prior to
conception if the cavernous angioma is accessible. For
those patients diagnosed during pregnancy
conservative management may be appropriate if the
mother is neurologically stable.

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Romanian Neurosurgery Vol. XVI nr. 1

FIG. 1 Axial and sagittal MRI scan showing cavernous

malformation in the pons

FIG. 2 Right occipital cavernoma

RADIOTHERAPY
The role of conventional radiotherapy and

stereotactic radiosurgery for deep cerebral cavernomas
is limited because of the possibility of incomplete
exclusion and the inherent risk of bleeding during the
latency period before definitive vascular obliteration.
Additionally, the risk of hemorrhage and of radiation
induced complications following stereotactic
radiosurgery for cavernous malformations are high.

Although radiosurgery has limited impact on the
control of hemorrhage, Gamma Knife radiosurgical
treatment is showing promise for the control of seizures

due to cerebral cavernoma. In 49 patients with drug-
resistant epilepsy, presumably caused by CM, that
were treated with GK, 26 patients (53%) were seizure-
free and another 10 patients had a significant decrease
in seizure frequency at follow-up (Regis). The authors
recommend that GK surgery be considered in the
treatment of refractory epilepsy when the cerebral
cavernoma is located in a highly functional area.

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