http://www.slideserve.com/henry/intracranialcavernoma
https://radiopaedia.org/articles/cerebralcavernous-venous-malformation?lang=us
Cerebral cavernous venous malformation
Dr Johannes Schmid and Dr Donna D'Souza ◉ et al.
Cerebral cavernous venous malformations, commonly known as cavernous
hemangioma or cavernoma, are common cerebral vascular malformations, usually
with characteristic appearances on MRI.
Cavernous malformations are found throughout the body. This article focuses on
cerebral cavernous venous malformations. For a general discussion and links to
cavernomas in other locations, please refer to the general article on cavernous
venous malformation.
Terminology
Many alternative terms have been used over the years including cavernous
hemangioma, cerebral cavernous malformation or simply cavernoma. As these
lesions are not neoplastic, it has been argued that the terms 'hemangioma' and
'cavernoma' should be avoided. Additionally, it is important to note that according
to newer nomenclature (ISSVA classification of vascular anomalies) these lesions
are merely known as slow flow venous malformations.
Having said all that, it is probably helpful in reports to include the word 'cavernous'
as this term is ubiquitous in the literature and most familiar to many clinicians.
For brevity, the term cavernous malformation is used in the remainder of this
article.
Epidemiology
Most patients who present symptomatically do so at 40-60 years of age. Most
patients have single lesions. Multiple lesions may be familial and screening of family
members may be indicated (see familial multiple cavernous malformation
syndrome). Additionally, cavernous malformations, along with capillary
telangiectasias, are commonly seen following cerebral radiotherapy 3.
Clinical presentation
The majority of lesions remain asymptomatic throughout life and are found
incidentally. Presentation due to hemorrhage may cause a headache, seizure or focal
neurological deficit. The risk of hemorrhage is 1% per year for familial cases and
somewhat less for sporadic lesions.
Pathology
Histologically cavernous malformations are composed of a "mulberry-like" cluster
of hyalinized dilated thin-walled capillaries, with surrounding hemosiderin 3. These
vessels are thrombosed to varying degrees. Unlike AVMs, there is no normal brain
between the interstices of these lesions.
On occasion, they are intimately associated with a developmental venous anomaly
(DVA), in which case they are known as mixed vascular malformation.
Radiographic features
Cerebral cavernous malformations tend to be supratentorial (~80% cases) but can
be found anywhere including the brainstem. They are usually solitary, although up
to one-third of patients with sporadic lesions have more than one 2.
CT
Unless large, these lesions are difficult to see on CT. They do not enhance. If large
they appear as a region of hyperdensity resembling blood products and speckles of
calcification. If there has been a recent bleed then the lesion is more conspicuous
and may be surrounded by a mantle of edema.
MRI
MRI is the modality of choice, demonstrating a characteristic “popcorn” or "berry"
appearance with a rim of signal loss due to hemosiderin.
•
T1: varied signal depending on the age of the blood products, small fluid-fluid
levels may be evident
•
T2
•
•
o
hypointense rim
o
varied signal internally depending on the age of blood products
o
if a recent bleed has occurred, surrounding edema may be present
GRE T2*/SWI
o
prominent blooming
o
useful for detecting smaller lesions otherwise missed by conventional spin
echo sequences, especially in patients with familial or multiple cavernous
malformations
T1 C+ (Gd): generally no enhancement, although possible 7
Cavernous malformations can be grouped into four types based on MRI appearances
using the Zabramski classification 11.
Angiography (DSA)
Cavernous malformations are angiographically occult and do not demonstrate
arteriovenous shunting.
Treatment and prognosis
Many cavernous malformations are asymptomatic and can be treated
conservatively. Symptoms can relate to mass effect, epileptic activity or repeated
hemorrhage. Symptomatic lesions should, when possible, be resected and complete
resection is curative 9.
Differential diagnosis
The differential, when cavernous malformations are numerous, is that of other
causes of cerebral microhemorrhages, including 2:
•
cerebral amyloid angiopathy: usually numerous small foci
•
chronic hypertensive encephalopathy: more common in the basal ganglia
•
diffuse axonal injury (DAI)
•
cerebral vasculitis
•
radiation-induced vasculopathy
•
hemorrhagic metastases
•
Parry-Romberg syndrome 2
Larger lesions can mimic:
•
hemorrhagic cerebral metastases
•
hemorrhagic primary brain tumors (e.g. ependymoma, glioblastoma)
Calcified lesions, such as old neurocysticercosis, or other infections
(e.g. tuberculoma) should also be considered.
References