Arachnoid cyst of the optic nerve: report of two cases and review of the literature.

PURPOSE: To describe two patients with arachnoid cysts of the optic nerve mimicking optic nerve/orbital neoplasms.

METHODS

The histories, ophthalmic examinations, and pathologic findings of two patients with arachnoid cysts of the optic nerves were reviewed and compared with previously reported cases.

RESULTS

One patient had progressive proptosis and the other had decreased vision with visual field changes. Pathologic examination of optic nerve sheath biopsies showed redundant proliferations of meningothelial cells with associated thickened dura.

CONCLUSIONS

Arachnoid cysts of the optic nerve are benign, slowly progressive conditions that may result in proptosis and visual field changes. The clinicopathologic features of arachnoid cyst should be differentiated from optic nerve sheath meningioma and other conditions.