Optic gliomas can be found in a variety of locations along the optic pathway:
- One or both optic nerves
- Optic chiasm
- Optic radiation
- Optic tracts
- Occipital lobes
Optic Nerve Gliomas
Optic nerve tumors generally remain within the orbit, but the tumor may extend:
- Through the optic canal to be partially intraorbital or partially intracranial.
- May also infiltrate other structures, such as the hypothalamus, the brain stem, and the basal ganglia.
- Very rarely may involve extension into the subarachnoid space with leptomentingeal metastasis.
These tumors are generally slow growing and may take many years to progress.
It can be hard to identify the origin of tumors that intimately involve both the chiasm and the hypothalamus.
Tumor may have initially arisen in the optic chiasm and then extended to involve the hypothalamus.
These tumors may also extend posteriorly along the optic tracts.
Raised intracranial pressure may be due to tumor growth into the ventricular system and obstruction of the Foramen of Monroe.