Intracanalicular meningioma with normal tomography. Case report.

A middle-aged woman presented with the typical symptoms and signs of a compressive optic nerve lesion. Plain skull films, tomography of the optic canals, and selective angiography with magnification and subtraction were normal. Computerized transaxial tomography clearly showed the tumor, which was a meningioma of the optic nerve sheath. At surgery the tumor was found within the optic canal with intracranial and orbital extensions. It was strictly intradural and did not involve the surrounding bone at any point. This case documents the fact that an intracanalicular meningioma may be associated with normal tomograms of the optic canal.