Introduction
Meningiomas are the most common primary intracranial tumour.
- ~80% of primary intraorbital meningiomas arise from the optic nerve sheath from the meningeal layers intraconal
- F>M ~40y
Dead Giveaways
WHO Grading:
Grade 1 (benign) --> fibrous, transitional, secretory, metaplastic
Grade 2 (anaplastic) --> choroid, clear cell, atypical
Grade 3 (malignant) --> Papillary, rhabdoid, anaplastic
Imaging:
The meningiomas appear isodense to optic nerve (seen in photo), and hyperdense to brain on CT.
On T1, it is isointense, but on T2 MRI, it is mildly hyperintense.
Meningioma is defined by a nearly normative intensity appearance, but swelling and bulging.
diagnostic features
Symptoms:
Slowly progressive exophthalmos over years
Proptosis related to intraconal location
Gradual vision loss due to ON compression
Optic disc oedema and eventual atrophy
Restricted ocular motility
Management:
Referral for excision in the case of aggressive tumours and poor vision radiotherapy for slow-growing tumours and good vision