Brain, meningeal, neural tumours

Question 1

Aetiology brain tumours?

Answer 1

• Few clearly defined RFx
• Ionising radiation (eg. radiotherapy/nuclear accident) increased risk meningioma and glioma
• No proven role electromagnetic radiation, other environmental
• Predisposing conditions

Question 2

Which conditions predispose to brain tumours?

Answer 2

• Neurofibromatosis 1 and 2

- Li Fraumeni Syndrome (p53 oss predisposes to glioma)

Question 3

Why are headaches worse in the morning?

Answer 3

• Increased blood return when prone

- Hypoventilation: increased CO2 ==> cerebral swelling

Question 4

What are the causes of cerebral mass effect progressing over several weeks?

Answer 4

• Primary brain tumour
• metastatic brain tumour
• brain abscess
• chronic subdural haematoma

Question 5

How is malignant astrocytoma defined histologically?

Answer 5

• Hypercellularity
• Cellular atypia and pleomorphism
• nuclear atypic/pleomorphism
• Mitoses
• Endothelial hyperplasia
• Necrosis/pallisading necrosis

Question 6

How may an intracranial mass present?

Answer 6

• Symptoms of raised ICP
• Seizures
• Focal neurological deficit

Question 7

What is the Monro-Kellie doctrine?

Answer 7

Cranial cavity rigid, increase in contents causes rise in pressure.
Some capacity for compensation but once critical point reached, small increases in volume result in large increases in ICP.

Question 8

What are the components of the cranial cavity (in order of importance)?

Answer 8

1) Brain
2) Arterial blood
3) Venous blood
4) CSF

Question 9

How does a rise in ICP alter the contents of the cranial cavity? (Related to Monro Kellie curve)

Answer 9

Get rid of contents from least to most important (i.e remove CSF -> venous blood ==> flat part of curve). Once arterial supply decreased ==> confusion. Hence steep part of curve.

Question 10

Rx of malignant astrocytoma?

Answer 10

• Steroid (dexamethasone): reduce oedema and ICP
• Resect as much as possible
• Adjuvant: radiotherapy, chemotherapy

Question 11

What is FLAIR MRI?

Answer 11

Fluid attenuated inversion recovery.

System represses signal from normal CSF (allows better visualisation of lesions near ventricles etc.)

Question 12

What is the pathology of low grade glioma?

Answer 12

-As for malignant astrocytoma but less abnormal for:
-hypercellularity
-cellular atypia/pleomorphism
-nuclear atypic/pleomorphism
Very few mitoses, no necrosis, invades diffusely, may have calcifications.

Question 13

What are low grade gliomas?

Answer 13

Oligodendroglioma
Astrocytomas
Mixed forms

Question 14

Common age of onset low grade glioma?

Answer 14

Often young (25-45).

Question 15

Survival of low grade glioma?

Answer 15

Prolonged (years to decades).

Question 16

What is a feature of metastatic brain tumours on FLAIR MRI?

Answer 16

Often cause intense cerebral oedema that causes more symptoms than the tumour mass.

Question 17

What are the common primary tumour sites causing brain metastases?

Answer 17

• Lung Ca
• Breast Ca
• Metastatic melanoma
• Renal Ca
• GIT Ca
• Unknown primary (15%)

Question 18

How are brain metastases treated?

Answer 18

• Steroids (dexamethasone)

- Surgical removal of mets if indicated

Question 19

When is surgery to remove brain mets indicated?

Answer 19

• If met is solitary
• If primary disease is stable
• If primary unknown (remove to confirm diagnosis)
• Multiple mets may be removed for palliation (i.e. relieve disabling symptoms)

Question 20

Characteristics of meningioma?

Answer 20

• Most common benign brain tumour
• Most common in middle age
• W>M
• Cause intense oedema

Question 21

Where do meningiomas arise?

Answer 21

Arachnoid cells in the meninges

Question 22

Where do meningiomas characteristically occur?

Answer 22

Falx, convexity and sphenoid wing.

Each has characteristic clinical syndrome.

Question 23

Pathology of meningioma?

Answer 23

• “Whorls”
• Multiple subtypes
• Malignancy infrequent

Question 24

Rx of meningioma?

Answer 24

• Total surgical excision

- Subtotal excision and diathermy of dural attachment if complete excision not possible