(#22099), and occasional CRV occlusion.  There is an increased association with von Recklinghausen's disease or neurofibromatosis.  On gross pathologic exam, one would see a smooth fusiform enlargement of the optic nerve(#22101), (#22102).  The tumor often extends into meninges causing meningeal hyperplasia which may make differentiation from an meningioma difficult on a superficial optic nerve biopsy.  Histopathologically, most optic nerve gliomas are Grade I or juvenile pilocytic (hair-like) astrocytomas.  These tumors consist of benign-appearing, round to spindle-shaped astrocytic nuclei with dendrite-like cytoplasmic processes(#22106).  Rosenthal fibers are a characteristic but not a diagnostic degenerative change--fusiform, cigar- shaped, eosinophilic structures within the astrocyte cytoplasmic processes(#22107).  Some lesions may also show small areas of necrosis within the tumors which show myxomatous cystic spaces.

-See also (#28088, #28091, #28094, #28097, #28100) for other views of optic nerve gliomas.