Decreased visual acuity, minimal proptosis, decreased eye movement and strabismus are the most common presenting symptoms. This is a neoplasm of the optic nerve which is also known as juvenile pilocytic astrocytoma. Optic nerve glioma in adults is a glioblastoma. Course ONGs grow very slowly and have similar pathology as juvenile pilocytic astrocytomas of the cerebellum. They typically begin intraorbitally and grow in a fusiform shape along the optic nerve toward the globe or toward the brain.
Malignant degeneration is very rare in children, but in adults, most die within a year of diagnosis.
If the tumor begins in the chiasm, it is likely to invade surrounding parenchyma regardless of age. ONGs may extend posteriorly to involve the chiasm, the optic tracts and the optic radiations. They often stabilize after childhood. The neoplasm is most often fusiform in shape, but can be tubular or excrescent. They rarely calcify, hemorrhage or become cystic.