November 2014
A 63-year-old man presenting with a 3-day history of vision loss
Neurologic exam: Left homonymous hemianopia, with no other deficits
Past medical history: Hypertension (BP=235/155 mmHg at admission) and depression
Malignant Optic Pathway Glioma
- Malignant optic pathway glioma in adulthood is extremely rare, with less than 50 cases reported.
- In contrast with the far more common optic glioma, in children with neurofibromatosis type 2 (NF-2), in adults without NF:
- The optic chiasm is frequently involved.
- It usually spreads contiguously beyond visual pathways (hypothalamus in 50%, temporal lobe in 22.5%, and basal ganglia in 15%).
- They are high-grade gliomas, classified pathologically as anaplastic astrocytoma or glioblastoma.
- Clinical Presentation: Subacute visual loss—monocular or hemianopia if optic nerve or chiasm is involved (respectively); typical signs of intracranial mass are usually absent.
- Key Diagnostic Features:
- Expansive and infiltrative mass involving any component of the optic pathway (optic nerve, chiasm or optic tract), which can extend to the contiguous structures.
- High signal on T2WI and low signal on T1WI, usually contrast-enhancing, with variable restricted diffusion and increased relative cerebral blood volume on perfusion
- Associated with mass effect and variable amounts of vasogenic edema
- DDx:
- Lymphoma
- Demyelinating disease
- Infectious and granulomatous disease
- Leukemia and metastasis
- Rx:
- Surgery, radiation, and/or chemotherapy, with poor results
- Malignant visual pathway gliomas grow fast and are rapidly fatal, with mean survival time being less than 1 year.
