Medial Sphenoid Wing Meningiomas

Abstract

Cushing was the first to systematize sphenoid wing meningiomas, dividing them into those arising from the inner third (deep, medial, or clinoidal third meningiomas), middle third (alar meningiomas), and outer third (pterional meningiomas) [3]. This distinction is still useful and practical today, not only because the respective symptoms differ, but also because the surgical problems, strategies, and goals vary greatly from one region to another. Clinoidal sphenoidal wing meningiomas grow mainly into the middle fossa and parasellar region. They may displace but usually surround the middle cerebral artery, supracavernous internal carotid artery, and optic nerve; the cavernous sinus may be compressed or invaded by these tumors. In large tumors the frontal and temporal, lobes are compressed from below and are separated by the tumor. The symptoms associated with this type of tumor growth consist mainly of visual disturbances in the form of decreased vision homolaterally and visual field defect due to compression of the lateral chiasm and proximal optic tract; seizures may also occur [2].