CNS tumours

Question 1

Define

Answer 1

DEFINITION: tumours of the central nervous system.

NOTE: brain tumours cannot be truly differentiated into benign and malignant because supposedly ‘benign’ tumours can cause significant morbidity and mortality

Instead they are differentiated into:

High-Grade = a tumour that grows rapidly and aggressively

• Glioma and glioblastoma multiforme
• Primary cerebral lymphoma
• Medulloblastoma

Low-Grade = a tumour that grows slowly and may or may not be successfully treated

• Meningioma
• Acoustic neuroma
• Neurofibroma
• Pituitary tumour
• Craniopharyngeoma
• Pineal tumour

Brain metastases commonly arise from:

1. Lung
2. Breast
3. Stomach
4. Prostate
5. Thyroid
6. Colorectal

Question 2

Causes

Answer 2

Can arise from any of the cells in the CNS (e.g. glial cells, ependymal cells, oligodendrocytes)

Question 3

Risk factors

Answer 3

Ionising radiation

Immunosuppression (e.g. HIV)

Inherited syndromes (e.g. neurofibromatosis, tuberous sclerosis)

Question 4

Epidemiology

Answer 4

Primary brain tumours = 2% of tumours diagnosed in the UK

AIDS patients have an increased risk of developing CNS tumours

Can develop at any age but are more common between 50-70 yrs

Question 5

Symptoms

Answer 5

Presentation depends on the size and location of the tumour

Headache (worse in the morning and when lying down)

Nausea and vomiting

Seizures

Progressive focal neurological deficits

Cognitive and behavioural symptoms

Papilloedema

Question 6

Investigations

Answer 6

• Bloods - check CRP/ESR to eliminate other causes (e.g. temporal arteritis)
• CT/MRI
• Biopsy and tumour removal
• Magnetic resonance angiography - define changing size and blood supply of the tumour
• PET

NOTE: distant metastases are RARE with primary CNS tumours