Insular Gliomas with Exophytic Extension to the Sylvian Cistern: A Glioma Growth Pattern That Has Gone Previously Unnoticed

Radiologic features that define the exophytic growth pattern in insular gliomas are the posterior displacement of the middle cerebral artery and a sharp subarachnoid margin that separates the exophytic tumor from the temporal pole. Contrary to the tumor that infiltrates the anterior perforating substance, the exophytic tumor is amenable for safe and complete resection.