Histologically classified venous angiomas of the brain: a controversy.

The term "venous angioma" (VA) usually refers to a developmental venous anomaly (DVA). However, a group of vascular malformations called VAs shows no venous abnormalities on angiography. The clinical and histological features of histologically classified VAs were studied in eight patients who presented with hemorrhage or seizures to reevaluate these venous anomalies. Angiography showed no venous abnormalities in six patients. Histological study included immunostaining for smooth muscle actin and glial fibrillary acidic protein. Surgical specimens of 10 cases of cavernous angiomas, 10 cases of arteriovenous malformations, and two cases of capillary telangiectasias were studied to compare these types of VAs. Angiographically occult VAs were surgically removed safely, whereas removal of DVAs was complicated by brain swelling and hemorrhagic infarction of the brain. Histological examination found angiographically occult VAs contained malformed and compactly arranged vessels with partly degenerated walls, whereas DVAs had dilated thin-walled vessels that were diffusely distributed in the normal white matter. This study of our cases and a review of the reported cases of VAs suggests that two different clinical and pathological entities are commonly categorized as "VA," angiographically occult VAs and DVAs. These two entities should be carefully distinguished.