Central nervous system (CNS) tumours

Question 1

What are CNS Tumours?

Answer 1

CNS tumours = primary malignancies arising from the brain or spinal cord

Encompasses over 130 different histologies
o Majority = glioma or meningioma

IC tumours
o Most malignant = brain
o Most benign = meninges

Spinal cord tumours
o Extradural or intradural

Question 2

Which solid tumours most commonly disseminate to the brain?

Answer 2

Lung cancer is the most common solid tumour disseminating to the brain (then breast and melanoma)

Question 3

What is the aetiology of CNS tumours?

Answer 3

Unknown aetiology – most thought to be sporadic
o <1% linked to lifestyle
o Ionising radiation is a known cause

Children = embryonic developmental errors

Question 4

What are the risk factors for CNS tumours?

Answer 4

• Ionising radiation

* Other cancers – lung, breast, melanoma

Question 5

Summarise the epidemiology of CNS tumours.

Answer 5

Second most common cancers of <25s (25%)

Almost half are diagnosed in >65s
o Highest incidence in over 90s

Overall, quite rare
o 3% of all malignancies
o 9th most common cancer in UK

Extradural are more common than intradural (spinal cord)

15% of all CNS tumours are from the spinal cord

Question 6

What are the general symptoms of brain tumours?

Answer 6

Symptoms are due to raised ICP, direct compression, IC shifting or secondary ischaemia

Non specific
o	Headache - Often a late complaint, Not isolated, Non-specific, tension-like
o	Altered mental status
o	Ataxia
o	Nausea and vomiting

General
o Focal seizures
o Fixed visual changes - Diplopia
o Speech deficits

Question 7

What are the location based symptoms of brain tumours?

Answer 7

o Frontal lobe = Altered mental status changes
o Temporal lobe = Emotional/behavioural changes
o Acoustic neuroma = Hearing loss, tinnitus
o Pituitary = Endocrine changes, visual field defects

Question 8

What are the symptoms of spinal cord tumours?

Answer 8

• Pain (usually lower back)
• Incontinence
• Rapid onset paralysis

Question 9

What are the signs of CNS tumours?

Answer 9

Brain
• Raised ICP - Papilloedema
• Directed compression - Cranial nerve palsies, Diplopia (CN6), Nystagmus

Spinal cord
• Decreased sensitivity in the saddle area
• Lower extremity weakness

Question 10

What are investigations done for CNS tumours?

Answer 10

Brain
•	CT head
•	Bloods
o	FBC
o	Coagulation screen
o	Electrolytes: Hypercalcaemia
o	ESR: Normal

Spinal cord
• Bone scan
• MRI spine