Cavernous malformation (cavernous angioma or cavernoma)
Vascular malformations are commonly divided into four categories: arteriovenous malformation, venous angioma, cavernous angioma/malformation, and capillary telangiectasias 1,2. This case is as example of a cerebral cavernous malformation.
A cavernous malformation or angioma is a hamartomatous "berry-like" collection of vascular spaces lined by thin walls devoid of smooth muscle 3. The characteristic feature is that it contains almost no intervening brain parenchyma among the abnormally enlarged, thin-wall endovascular channels 1. Surrounding brain parenchyma is often gliotic and hemosiderin-stained, and may contain small low-flow feeding arteries and draining veins 3. They appear to grow by a process of cavern proliferation in the setting of repetitive lesional hemorrhages (hemorrhagic proliferative dysangiogenesis) 4.
The peak incidence occurs between 40–60 years of age. Most patients have a single lesion which remains clinically silent and usually presents as an incidental finding on neuroimaging. When symptomatic, patients commonly present with seizures and progressive neurological deficits 1,4.
The radiological appearance of cavernous malformations is variable on CT and MRI. On pre-contrast CT, the lesion commonly appears 1:
- hyperdense, but mixed hyperdense and isodense lesions have been described
- mass effect is frequently present and occasionally secondary to hematoma, is frequently present
Contrast administration may improve the delineation of the lesion with faint enhancement1-4.
High-field MR imaging is considered the radiographic “golden standard” for the diagnosis and evaluation of cavernous malformations 2. This demonstrates characteristic “popcorn” appearance of the lesion, with a low signal intensity of the rim due to hemosiderin deposition 1-4.
Incidental lesions are usually managed conservatively. Symptomatic cavernous malformations can be surgically excised 1-4. However, the potential risks and benefits of surgery for each patient must be diligently discussed prior to removal of these benign malformations.
Case courtesy of Dr. Frank Gaillard.