Cavernous angiomas.

These are developmental malformations of the vascular bed. These congenital abnormal vascular connections frequently enlarge over time. The lesions can occur on a familial basis. Patients may be asymptomatic, although they often present with headaches, seizures, or small parenchymal hemorrhages

Cavernous angiomas are considered to be congenital vascular hamartomas composed of closely approximated endothelial-lined sinusoidal collections without significant amounts of interspersed neural tissue. The lack of intervening neural tissue is the only histopathologic characteristic that distinguishes these lesions from capillary telangiectasias. Cavernous angiomas represent approximately 1% of intracranial vascular lesions and 15% of cerebrovascular malformations. Cavernous angiomas can occur at any age, but they are most likely to become clinically apparent in patients aged 20-40 years.

Cavernous angiomas can be found in any part of the brain because they can occur at any location along the vascular bed. Frontal and temporal lobes are the most common sites of occurrence, and 80-90% of the lesions are supratentorial. The deep cerebral white matter, corticomedullary junction, and basal ganglia are common supratentorial sites, whereas the pons and cerebellar hemispheres are common posterior fossa sites.

MRI findings of parenchymal cavernous angiomas demonstrate typical, popcornlike, smoothly circumscribed, well-delineated complex lesions. The core is formed by multiple foci of mixed signal intensities, which represents hemorrhage in various stages of evolution. Cavernous malformations are considered angiographically occult.