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25% CT/MRI done in wrong place or mis-read

Helps to know what you're looking for

Optic Nerve Glioma

optic nerve, chiasm or diffuse

benign pilocytic astrocytoma, frequently Neurofibromatosis, esp if absent sphenoid wing

70% in first decade; 90% by second

At what point image child with known NF for ON glioma

CT was first improvement over plain films and showed fusiform lesion with no reactive bone changes

MRI also shows fusiform enlargement ON, with mucinous material around the ON

Conservative mgmt

- observe annually

Indications for intervention

- blind proptotic eye, progressive growth,

Surgical approach discussed with issues of how it fuses with many structures

Can MRI identify the tumor free margin?

- this was studied 25 years ago with plain films and CT so wanted to compare

- vision typically bad on presentation except in one patient

- reviewed surgical details based on location within the optic nerve

- findings: MRI not anymore reliable in localizing but could be related to reactive gliosis interpreted as involvement/recurrence

Optic Meningioma

- vision loss slow and progressive

- can be confused with optic neuritis esp in young women

- transient obscuration

- rare nerve swelling

- confounding inflammatory, infiltration, infectious diseases

MRI the gold standard with preservation of optic nerve within the tumor

Conservative management

- slow growth therefore monitor q6/12 with MRI annually

- biopsy very rare - for atypical cases

- transorbital excision?

- transcranial resection no longer has a role unless NLP and proptosis; resection is NOT simple as infiltrative

- RadioTx was considered; as no other medical therapy and surgery more harm than good

- fractionated external beam radiation; no role for gamma knife

- Surgery only vs radiation only groups compared to observed only

- vision better preserved with radiation than with surgery which resulted in lost vision abruptly...even worse if surgery plus radiation