NEURO - Brain tumours & raised ICP

Question 1

Bimodal peaks of brain tumour epidemiology

Answer 1

–Peak in infancy and childhood

–Peak in 7th decade of life

Question 2

Types of common brain tumours

Answer 2

•Neuroepithelial tumours (gliomas) 52%

• Astrocytoma (all grades) 44%
• Ependymoma 3%
• Oligodendroglioma 2%
• Medulloblastoma 3%
• Metastatic tumours 15%
• Meningioma 15%
• Pituitary adenoma 8%
• Acoustic neuroma 8%

Question 3

Etiology of brain tumours

Answer 3

Environmental (ionising radiation, radiotherapy, nuclear explosions)

Genetic (Neurofibromatosis 1 & 2, Li Fraumeni syndrome)

Question 4

(4) DDx of raised intracranial pressure with focal neurological deficits suggesting an intracranial mass enlarging over a few weeks

Answer 4

–Primary brain tumour
–Metastatic brain tumour
–Brain abscess
–Chronic subdural haematoma

Question 5

Features of glioblastoma multiforme

Answer 5

Heterogeneous deep temporal mass with patchy contrast enhancement and areas of necrosis. (pallisading necrosis)

The optic radiation and internal capsule are compressed or invaded by the tumour

Question 6

Describe malignant astrocytoma

Answer 6

•Gliomas comprise 50% of all brain tumours
•50% gliomas are malignant astrocytomas
–Glioblastoma multiforme (WHO grade 4)
–Anaplastic astrocytoma (WHO grade 3)

• 6th-8th decade of life
• Eighth most common cause of cancer death
• Prognosis is dismal – median survival 7-14 months for glioblastoma multiforme

Question 7

Features of malignant cells by pathology

Answer 7

—Hypercellularity
Cellular atypia/pleiomorphism
Nuclear atypia/pleiomorphism
Mitoses
Endothelial hyperplasia
Necrosis / pallisading necrosis

Question 8

Px of intracranial mass

Answer 8

•Symptoms of raised intracranial pressure
•Seizures (40-80%)
•Focal neurological deficit: Depends on location of mass
•Duration of symptoms depends on rate of growth of mass
-Growth rate depends on grade of tumour
-Weeks to years

Increased ICP
–Headache
–Nausea and vomiting
–Drowsiness

Question 9

What may cause increased ICP?

Answer 9

–Tumour mass
–Surrounding oedema
–Hydrocephalus if CSF pathways are blocked
–other extra volumes (bleeding)

Question 10

Which lobe must be affected for dysphasia?

Answer 10

Dominant frontal or temporal lobe

Question 11

Rx of malignant astrocytoma

Answer 11

•Commence steroids (dexamathasone)
–Reduction of cerebral oedema and ICP

•Resection of as much of the tumour as is safely possible
–If resection not possible then biopsy only

•Adjuvant therapy
–Radiotherapy and chemotherapy
–May be given in various combinations depending on the tumour grade

Question 12

Features of a low grade glioma

Answer 12

Homogeneous mass best seen on FLAIR/T2-weighted MRI with no contrast enhancement and minimal mass effect

(c.f. heterogenous mass with patchy contrast enhancement in GBM; high grade glioma)

Question 13

Describe a low grade glioma

Answer 13

•Includes oligodendroglioma, astrocytomas- and mixed forms
–WHO Grade 1 (usually children) and 2 (adults)

•Patients are young (25-45), neurologically intact, often only with seizures

•Survival is prolonged (years to decades)
–But eventual growth of low grade tumour or progression to a higher grade will occur

Question 14

Rx of low grade glioma

Answer 14

–Removal of as much tumour as safely possible
–Often only a biopsy to avoid deficit
–Tissue diagnosis essential
–Defer radiotherapy and chemotherapy until tumour progression

Avoid SE as much as possible

Question 15

What often causes intense cerebral oedema that causes more symptoms than the actual mass itself?

Answer 15

Metastatic brain tumour

Comprise approximately 15% of brain tumours in clinical series

Interval between diagnosis of primary tumour and brain metastases is highly variable

Common in cerebellum – may cause obstructive hydrocephalus

Question 16

Commonest primary tumours that metastasise to the brain

Answer 16

Lung, breast, melanoma, kidney, GI (bowel)

Question 17

Rx of brain metastases

Answer 17

•Commence steroids (dexamathasone)
–Reduction of cerebral oedema and ICP

•Surgery to remove the metastasis is indicated
–If the metastasis is solitary
–If the primary disease is stable and the patient has a reasonable life expectancy

•If the primary cancer is unknown the metastasis should be removed to confirm the diagnosis

•Occasionally one of multiple metastases will be removed for palliation
–If it is causing disabling symptoms, such as a hemiparesis, that can be improved by removal, even if the patient may only live a few months

•Whole brain radiotherapy (45 Gy)
–For multiple metastases
–After removal of a single metastasis (controversial)

•Stereotactic radiotherapy
–Single high dose focused radiation for 1 – 3 metastases

•Chemotherapy and targeted agents generally have poor penetration into the brain

Question 18

Describe meningioma

• how common
• epidemiology
• origin of cells
• Px

Answer 18

•Most common benign brain tumour
•Most common in middle age
•More common in women than men
•Arise from arachnoid cells in the meninges
Slow-growing, therefore may reach a very large size
•Symptoms may be present for years
•May be asymptomatic and discovered incidentally

Question 19

Characteristic locations of meningioma

Answer 19

on the dura
•Most common is falx, convexity and sphenoid wing
•Each location has a characteristic clinical syndrome
•Often associated with intense oedema

Question 20

Pathology of meningioma

Answer 20

—“Whorls” are a common feature

Subtypes generally have no prognostic significance
—
A few subtypes portend a poorer prognosis
—
Malignancy is infrequent

Question 21

Rx of meningioma

Answer 21

• Total surgical excision and obliteration of the dural attachment is the most effective treatment
• Subtotal excision and diathermy of the dural attachment if complete excision not possible
• Radiosurgery or radiotherapy for small, residual, recurrent or malignant tumours
• Extent of resection is related to risk of recurrence