Brain tumours

Question 1

What are examples of intrinsic tumours found in the CNS?

Answer 1

• Astrocystoma
• Glioblastoma
• Oligodendroglioma
• Ependymoma
• Choroid plexus papilloma
• Haemangioblastoma

Question 2

What is an astrocytoma?

Answer 2

Tumour arising from astrocytes. It is thought that many anaplastic astrocytomas arise as a consequence of dedifferentiation within a pre-existing astrocytic neoplasm. The prognosis for patients with astrocytomas (and gliomas generally) depends on the degree of tumour differentiation, the age of the patient at diagnosis, and the site and size of the neoplasm.

Question 3

What percentage of primary brain tumours do astrocytomas account for?

Answer 3

10%

Question 4

What percentage of primary CNS tumours do glioblastomas account for?

Answer 4

30%

Question 5

Where do most glioblastomas arise?

Answer 5

Cerebral hemispheres

Question 6

What is glioblastoma?

Answer 6

Glioblastomas are characterised histologically by a pleomorphic tumour cell population. Although some glioblastomas may arise de novo, many arise as a consequence of dedifferentiation within a pre-existing astrocytoma. Dedifferentiation is accompanied by, or is the result of, a series of genetic events. Mitotic activity in glioblastomas is abundant, and vascular endothelial proliferation and necrosis are prominent.

Question 7

What are Oligodenrogliomas?

Answer 7

Ill-defined, infiltrating neoplasms, usually arising in the white matter of the cerebral hemispheres. In a well-differentiated tumour, the neoplastic cells are small, rounded and uniform. Small foci of calcification are common, and an interweaving vascular pattern is often present.

Question 8

What is an ependymoma?

Answer 8

Ependymomas arises from an ependymal surface, usually in the fourth ventricle, and project into the CSF pathway. Most ependymomas are well differentiated, and extensive invasion of adjacent CNS structures is uncommon.

Question 9

What is a haemangioblastoma?

Answer 9

Haemangioblastoma is an uncommon neoplasm arising most often in the cerebellum and forming a well-defined, frequently cystic mass. Histologically, the tumour is composed of blood vessels, separated by irregular stromal cells.

Question 10

What syndrome is haemangioblastoma associated with?

Answer 10

von-Hippel-Lindau

Question 11

What are extrinsic tumours of the CNS?

Answer 11

• Meningioma
• Schwannoma
• Neurofibroma

Question 12

Are astrocytomas malignant?

Answer 12

Yes

Question 13

Are Oligodendroglioma’s malignant?

Answer 13

Yes

Question 14

Are Ependymomas malignant?

Answer 14

Yes

Question 15

Are meningiomas malignant?

Answer 15

No

Question 16

Are neurofibroma’s malignant?

Answer 16

No

Question 17

What are gliomas?

Answer 17

Malignant tumours of neuroepithelial origin are usually seen within the hemispheres, but occasionally in the cerebellum, brainstem or cord.

Examples include Astrocytomas, Glioblastoma, Oligodendroglioma

Question 18

What are meningiomas?

Answer 18

Meningiomas arise from cells of the arachnoid cap (a component of arachnoid villi). The most frequent sites are the parasagittal region, sphenoidal wing, olfactory groove and foramen magnum. Meningiomas are smooth lobulated masses, which are broadly adherent to the dura. Infiltration of the adjacent dura and overlying bone is common, but invasion of the brain is rare. The brain, however, may be markedly compressed by a meningioma, resulting in considerable anatomical distortion

Question 19

What are schwannomas?

Answer 19

Schwannomas derive from Schwann cells in the nerve sheath of the intracranial or intraspinal sensory nerve roots. By far the commonest site is the vestibular branch of the 8th cranial nerve in the region of the cerebello-pontine angle; such neoplasms are often known as ‘acoustic neuromas’.

Question 20

What are neurofibromas?

Answer 20

In the CNS, neurofibromas usually arise on the dorsal nerve roots of the spinal cord. Unlike schwannomas, neurofibromas are not encapsulated, but tend to involve an entire nerve root, occasionally involving several nerves (plexiform neurofibroma).

Question 21

What are the most common sites for secondary mets to spread from into the brain?

Answer 21

• Bronchus
• Breast
• Stomach
• Prostate
• Thyroid
• Kidney

Question 22

What are clinical features of a CNS tumour?

Answer 22

• Direct effect features
• Signs of raised ICP
• Seizure activity - focal/generalised

Question 23

What are examples of false localising signs that can be seen in brain tumours?

Answer 23

• VIth nerve lesion - first on the side of a mass and later bilaterally as the VIth nerve is compressed or stretched during its long intracranial course.
• IIIrd nerve lesion - develops as the temporal lobe uncus herniates caudally, compressing III against the petroclinoid ligament
• Ipsilateral Hemiparesis - from compression of the contralateral cerebral peduncle on the edge of the tentorium.

Question 24

Are meningiomas slow growing or fast growing?

Answer 24

Slow growing

Question 25

What symptoms might suggest a brain tumour?

Answer 25

• Raised ICP headache
• Nausea/vomiting
• Visual distrubance
• Somnolence
• Cognitive impairment
• Altered consciousness

Question 26

What are signs that might be present in someone with a brain tumour?

Answer 26

• Papilloedema
• CNVI/III palsy
• Decreased GCS
• Hemiparesis
• Focal signs

Question 27

How would you investigate someone with suspected brain tumour?

Answer 27

• CT/MRI
• Tests to rule out extracranial primary source - CT chest/abdo/pelvis, mammography, lymph node biopsy
• Biopsy

Question 28

What are the general priciples to management of a brain tumour?

Answer 28

• Corticosteroids - cerebral oedema
• Anticonvulsants - seizures
• Analgesia
• Anti-emetics
• Surgery
• Radio/chemotherapy
• Endocrine replacement - pituitary adenoma

Question 29

What is the average survival of glioblastoma multiforme?

Answer 29

Approximately 1 year