Central Nervous System Tumour

Question 1

Define CNS tumour

Answer 1

Primary tumours arising from the brain parenchyma (10%)

Secondary metastases from lung, melanoma, breast, leukaemia/lymphoma (90%)

Question 2

What are the causes/risk factors of CNS tumours?

Answer 2

Meninges
• Meningiomas

Glial cell (gliomas)
• Glioblastoma
• Astrocytoma
• Oligoastrocytoma
• Oligodendroma
• Ependymoma

Nerve sheath
• Schwannoma
• Neurofibroma

Embryonal
• Medulloblastoma
• Neuroblastoma

Blood vessels
• Angioma

Other
• Pituitary adenomas

Question 3

What are the symptoms of CNS tumours?

Answer 3

Raised ICP
• Headaches
• Nausea & vomiting
• Seizures

Focal neurological symptoms
• Drowsiness
• Personality changes
• Memory problems
• Speech deficit
• Dysphagia
• Hemiparesis
• Gait disturbance
• Altered mental status
• Diplopia

Question 4

What are the signs of CNS tumours?

Answer 4

Raised ICP
• Papilloedema
• Bradycardia

Focal neurological signs
• Ophthalmoplegia e.g. cranial nerve palsies, gaze palsy
• Visual field defects e.g. bilateral hemianopia, homonymous hemianopia
• Parinaud’s syndrome (pineal tumours) – impaired upgaze
• Cerebellopontine lesion – unilateral deafness, facial weakness/paraesthesia, ataxia,
• Anosmia
• Agnosia
• Ataxia

Question 5

What investigations for CNS tumours?

Answer 5

• CT Head - usual initial investigation.
• MRI Brain - higher sensitivity.
- Diffusion-weighted-imaging and MR spectroscopy can be helpful in characterising lesion without biopsy.
• fMRI - functional MRI may be necessary if the lesion is located in dominant hemisphere for surgical planning.
• CXR or CT-CAP -
to determine if the lesion is secondary or primary.
• Brain Biopsy - type and grading (degree of differentiation of tumour).
• LP - lumbar puncture is a relative contraindication if there is evidence of raised intracranial pressure, may cause herniation.
• Other Ix - HIV Screen, toxoplasma serology and TB tests.