SURGICALLY VERIFIED CASE OF OPTIC SHEATH NERVE MENINGOCELE - CASE-REPORT WITH REVIEW OF THE LITERATURE

Optic sheath meningocele is rare; only approximately 31 cases have bee n reported. The term optic sheath meningocele has recently been propos ed by Garrity and Forbes to describe primary CSF cysts of the optic ne rve sheath, without apical mass or malformation of the cranio-orbital junction. Presenting symptoms are often related to involvement of the optic nerve, with a slow or rapid decrease of visual acuity. CT and MR I studies reveal a tubular-cystic enlargement of the optic nerve/optic sheath complex (on/onsc), with thickening of the optic nerve. Radiolo gical differential diagnosis should include optic nerve tumors such as gliomas, meningiomas, and arachnoid cysts involving the optic nerve s heath. Up to now, it seems that early surgical management by means of optic nerve/optic nerve sheath decompression affords an improvent of v isual function with minimal morbidity in patients who present a rapid decrease of visual acuity within 3-6 months. We present an additional case and discuss the clinical, radiological, and operative features of this pathological condition of the optic nerve sheath.