Surgical treatment for OPG involves either biopsy or excision of the tumor.
Surgery is usually the first choice when:
1. Single nerve involvement is causing:
- Progressive disfiguring proptosis
- Blindness
2. An exophytic chiasm tumor is causing mass effect or hydrocephalus.
Biopsy:
Provides histologic confirmation.
However, biopsy can be associated with some risk and is not always recommended for typical chiasmatic lesions involving visual pathway - the radiological appearance and clinical presentation is usually typical for a low grade astrocytoma.
Excision
The tumor must be readily accessible to allow complete excision.
Excision can fail if the resection margins are positive – e.g. if disease extends into the chiasm. Diffuse infiltration of the chiasm is a contra-indication to surgery. At the optic chiasm, there is little data to support surgical resection.
Decompression or limited resection may be of some value in restoring vision in some tumors.
Partially infiltrating low-grade astrocytomas can be resected with little visual compromise. Half of these can remain stable without further intervention for 3-5 years.
There are some case reports of spontaneous tumor regression after partial resection.
- Tend to have less localized disease and an increased risk of local recurrence after surgery than non-NF patients.
- In one study, patients with NF and completely excised optic pathway glioma were twice as likely to recur than non-NF patients.
