Glioma of optic nerve is associated with ?
Neurofibromatosis type I
Neurofibromatosis type II
Both the above
None of the above
Ans. is 'a' i.e., Neurotibromatosis type I Optic nerve glioma 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). Patients present with some degree of unilateral visual dysfunction, visual field loss, afferent pupillary defect, decreased ocular motility, optic atrophy, pain headache and nystagmus. Proptosis is often the chief complaint of an orbital glioma. Nystagmus may also occur. Other late features of optic nerve glioma are neovascular glaucoma, anterior segment ischemia and hemorrhagic glaucoma from retinal vascular occlusion. In chiasmal gliomas there may be visual field defects, raised ICT, papilloedema and endocrine abnormalities like diabetes insipidus, hypopituitarism, dwarfism and precocious pubey.