Central Nervous System (CNS) Tumours

Question 1

What are the types of CNS tumours

Answer 1

=> tumours of neuroepithelial tissue

• Astrocytoma
• Oligodendroglioma

=> Tumours of the nerve sheath
- Schwannoma
Neurofibroma

• Lymphoma

=>Germ cell tumours

• Germinoma
• Teratoma

=> sellar region

• Pituitary adenoma
• Craniopharyngioma

=>Meningiomas

=>Metastases

Question 2

What is the most common cause of a CNS tumour

Answer 2

Metastases

Often from: 
LUNG
BREAST
Kidney 
Stomach 
Colon 
Melanoma

Question 3

What CNS tumours are the most common primary brain tumour and benign tumour

Answer 3

Primary tumour - astrocytoma

Benign tumours - meningioma and acoustic neuroma

Question 4

General symptoms of a CNS tumour

Answer 4

Raised ICP headache (worse on waking up, lying down, leaning forward + morning nausea)
Nausea and vomiting
FLAWS
Symptoms of area compression

Question 5

General signs of CNS tumours on examination

Answer 5

Papilloedema on fundoscopy (Raised ICP)

Cushing’s reflex: bradycardia, hypertension, irregular breathing

Vestibular schwannoma - loss of corneal reflex

Bitemporal hemianopia: craniopharyngioma + pituitary adenoma

Question 6

Describe astrocytomas (aetiology + signs)

Answer 6

Can form glioblastoma multiforme (GMB), the most common primary brain tumour

Signs - Focal neurological deficits according to location (e.g., frontal, temporal, cerebellum, brainstem) or with signs of elevated intracranial pressure

Question 7

Describe Oligodendroglioma (aetiology)

Answer 7

Slow-growing, defined tumour originating from oligodendrocytes
Common in frontal lobes

Question 8

Describe schwannomas (aetiology + symptoms + signs)

Answer 8

Non-invasive and slow-growing tumour of schwann cells that surround cranial nerve roots/peripheral nerves

Vestibular schwannoma/acoustic neuroma = tumour from CNVIII = loss of corneal reflex
+ Hearing loss
+ Facial paralysis
+ Tinnitus

Question 9

Describe neurofibroma (aetiology)

Answer 9

Originate from Schwann cells, fibroblasts or perineural-like cells
Higher risk of malignancy than schwannomas
Involve spinal nerve roots or peripheral nerve

Question 10

Describe CNS lymphomas (aetiology + signs)

Answer 10

Forms around periventricular parenchymal blood vessels
Solitary or multifocal
Generally in immunocompromised patients
Associated with EBV infection in HIV +ve patients

Signs: lymphadenopathy

Question 11

Describe the germ cell tumours of the CNS

Answer 11

Germinoma: primitive spheroidal cell tumour

Teratoma: contains a mixture of well differentiated tissues originating from the germ cell layers -> forms dermis, muscle, bone, teeth, hair etc.

Question 12

Describe Craniopharyngioma

Answer 12

Most common paediatric supratentorial tumour

Solid/cystic tumour of the sella region, derived from the remnants of Rathke’s pouch

Symptoms:
Hormonal disturbance
Hydrocephalus

Question 13

Describe meningiomas (aetiology + symptoms)

Answer 13

Second most common primary brain tumour
Typically benign tumours that arise from the dura mater of the meninges

Symptoms:
Neurological deficit + progressive, focal or general headaches

Question 14

Investigations for CNS tumours

Answer 14

Gadolinium-enhanced MRI: preferred initial investigations - shows hypointense on T1 or hyperintense on T2
Biopsy: confirms type of tumour

Pituitary function tests: If pituitary tumour/craniopharyngioma is suspected

CT head: detects 90%
CT CAP/CXR/PET: mets

EEG: evaluate functional changes
CSF analysis: (LP often CI)