Optic nerve glioma is associated with-

Ans. is 'b' i.e., Neurofibromatosis I * Optic nerve glioma (astrocytoma) is the most common intrinsic tumor of the optic nerve. Most common type of optic nerve glioma is juvenile pilocytic astrocytoma.* The majority of optic nerve gliomas are of astrocytic origin. However, a few rare optic nerve gliomas arise from oligodendrocytes. 70% of optic gliomas occur during first decade of life.* Optic nerve gliomas are associated with Neurofibromatosis-1 (Von Recklinghausen's disease) in 55% of cases.* 75% of optic gliomas arise from optic chiasma and adjacent optic nerve. 25% are confined to optic nerve alone (orbital optic nerve glioma).