Meningioma
Meningioma is a primary extra axial tumour arising from arachnoid cap cells.
Most are slow growing and benign, but biological behaviour ranges from indolent incidental tumours to aggressive recurrent malignant disease.
Common locations include:
- Cerebral convexity
- Parasagittal region
- Sphenoid wing
- Olfactory groove
- Tuberculum sellae
- Petroclival region
- Posterior fossa
- Foramen magnum
- Spinal canal
Symptoms result from:
- Brain compression
- Cranial nerve compression
- Venous sinus involvement
- Peritumoral oedema
- Seizures
WHO grading
WHO grade 1
Most meningiomas.
Generally slower growing.
WHO grade 2
Includes atypical, clear cell and chordoid meningiomas and tumours meeting higher mitotic or brain invasion criteria.
Higher recurrence risk.
WHO grade 3
Aggressive malignant meningioma.
A TERT promoter mutation or homozygous CDKN2A/B deletion is sufficient for WHO grade 3 designation even when histological appearance is not frankly anaplastic.
Simpson resection grading
Useful for describing surgical completeness.
Grade I
Complete tumour removal plus involved dura and abnormal bone.
Grade II
Complete tumour removal with coagulation of dural attachment.
Grade III
Complete tumour removal without resection or coagulation of dural attachment or involved extradural tissue.
Grade IV
Subtotal tumour removal.
Grade V
Simple decompression or biopsy.
Modern management does not sacrifice critical venous sinuses or cranial nerves solely to achieve a lower Simpson grade when the neurological morbidity would outweigh recurrence benefit.
