New CT finding in aggressive meningioma.

The computed tomographic (CT) findings in aggressive or invasive meningiomas have been described by several authors [1-3]. These signs include heterogeneous contrast enhancement with or without cystic components, irregular tumor margins , and marked surrounding edema. Recently , "mushrooming" has been added as an additional CT finding [4]. According to Taveras and Wood [5], the angiographic demonstration of deep draining veins in meningiomas implies underlying invasion of brain tissue and indicates tumor aggressiveness. We describe two cases of proven aggressive meningioma in which these deep draining veins were seen on contrast-enhanced CT. To our knowledge, the significance of this CT finding has not been reported before. We also reviewed 100 cases of nonaggressive meningiomas and found no instances of deep draining veins on contrast-enhanced CT scans .