Introduction
A benign tumour consisting of astrocytes and glial cells that slowly grows from the optic nerve, chiasm or tract.
- Primarily associated with NF1, and should be considered if bilateral
- Primarily affects children of ~8 years
- Malignancy (very rare) typically affect males in adulthood, but have devastating consequence and almost certain death
- 10% manifestation in the optic nerve
- 1/3 involves both optic nerve and chiasm
- 1/3 only chiasm
- 25% in the hypothalamus
- 5.5% multicentric.
Dead Giveaways
Diagnostic Tools:
Primarily involves imaging techniques
The CT scan and MRI scan both help to reveal the enlargement especially on the optic nerve (seen in the picture)
On Type 1 MRI, tumours are hypointense, but on Type 2, they are hyperintense, and so T2 is typically utilised more
In patients with neurofibromatosis 1, the lesions can appear irregular with mixed low-density areas.
diagnostic features
Symptoms:
Proptosis
Gradual vision loss
Optic atrophy/oedema
VF defect likely, and will change appearance depending on location of glioma
Prognosis:
Unless progression to a glioblastoma occurs, prognosis is typically very good.
If untreated, can cause massive swelling, bilateral vision loss, haemorrhaging, transient vision loss,
Optociliary collaterals can appear, along with CRVO