Brain tumours Flashcards

1
Q

Whats the difference between malignant and benign brain tumours?

A

Malignant = do not metastasise outside CNS, occur within the substance of the brain.

Benign = extrinsic, ie occur outwith the CNS

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2
Q

Name some malignant tumours

A

Neuropithelial tissue - glioma

Embryonal tumours - medulloblastoma

Lymphoma (in immunosupressed)

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3
Q

Name some benign tumours

A

Meninges - meningioma

Pituitary - adenoma

Neurofibroma

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4
Q

What are examples of intrinsic tumours found in the CNS?

A
  • Astrocystoma
  • Glioblastoma
  • Oligodendroglioma
  • Ependymoma
  • Choroid plexus papilloma
  • Haemangioblastoma
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5
Q

Name some gliomas

A

Astrocytoma, medulloblastoma, ependymomas, oligodendrogliomas

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6
Q

What is an astrocytoma?

A

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.

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7
Q

What gene is associated with astrocytomas?

A

P53

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8
Q

How are astrycytomas graded?

A

WHO grade 1-4

1+2 = benign course

3+4 = malignant course

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9
Q

What is gliobastoma multiforme?

A

Grade 4 astrocytoma. Leads to necrosis and cyst formation, spreads through white matter and CSF pathways.

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10
Q

What percentage of primary brain tumours do astrocytomas account for?

A

10%

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11
Q

What percentage of primary CNS tumours do glioblastomas account for?

A

30%

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12
Q

Where do most glioblastomas arise?

A

Cerebral hemispheres

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13
Q

What is glioblastoma?

A

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.

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14
Q

What are Oligodenrogliomas?

A

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.

Slow growing

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15
Q

What is an ependymoma?

A

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.

Usually affects 4th ventricle

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16
Q

What are medulloblastomas?

A

Commonest astryocytoma in children, arrised in cerebellum

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17
Q

What is a haemangioblastoma?

A

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.

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18
Q

What syndrome is haemangioblastoma associated with?

A

von-Hippel-Lindau

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19
Q

What are extrinsic tumours of the CNS?

A
  • Meningioma
  • Schwannoma
  • Neurofibroma
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20
Q

Are astrocytomas malignant?

A

Yes

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21
Q

Are Oligodendroglioma’s malignant?

A

Yes

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22
Q

Are Ependymomas malignant?

A

Yes

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23
Q

Are meningiomas malignant?

A

No

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24
Q

Are neurofibroma’s malignant?

A

No

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25
What are gliomas?
Malignant tumours of neuroepithelial origin are usually seen within the hemispheres, but occasionally in the cerebellum, brainstem or cord. Examples include Astrocytomas, Glioblastoma, Oligodendroglioma
26
What are meningiomas?
## Footnote Meningiomas arise from cells of the arachnoid cap (a component of arachnoid villi) **(arise from arachnoid cells in meninges)**. 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
27
What genetic abnormality is associated with meningiomas?
Chromosome 22 loss in 70%
28
Typical characteristics of a meningioma
Benign and slow growing Extra-axial so usually affects brain by external expression. Frequently occurs along the falx, convexity or sphenoid bone USUALLY CURE IF COMPLETELY SURGICALLY EXCISED
29
What are schwannomas?
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’.
30
What are the features of an acoustic neuroma?
Initially puts pressure on CN's 5 and 7 (then 9, 10,12 as it expands) Arises from cerebellopontine angle Unilateral deafness, facial weakness, unilateral ataxia, hemifacial numbness Sugical excision but risks nerv damage
31
What are neurofibromas?
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).
32
What are the most common sites for secondary mets to spread from into the brain?
* **Bronchus** * **Breast** * **Stomach** * **Prostate** * **Thyroid** * **Kidney**
33
What are clinical features of a CNS tumour?
* **Direct effect features** * **Signs of raised ICP** * **Seizure activity** - focal/generalised
34
What are examples of false localising signs that can be seen in brain tumours?
* **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.
35
Are meningiomas slow growing or fast growing?
Slow growing
36
What symptoms might suggest a brain tumour?
* **Raised ICP headache** * **Progressive focal neurological deficit** * **Focal or generalised epilepsy** - seen in \<50%, exclude space ocupying lesion in all adult onset seizures * **CSF obstruction** - obstructive hydrocephalus: severe headache, sometimes with collpase/loss of consciousness
37
Signs of raised ICP
Presenting feautre in 20% * Headache - typically early morning, worse on coughing, straining, bending, lying down etc * Gait ataxia * 3rd and 6th nerve palsy * N+V * Papilloedema * Seizure * Altered consciousness - stupor/coma (reduced GCS) * Cognitive impairment * Visual disturbance * Drowsiness (BAD!)
38
Signs/symptoms when the frontal lobe is affected
Hemiparesis, personality change, apathy, intellectual decline, Broca's dysphasia
39
Signs/symptoms when the temporal lobe is affected
Dysphasia, contralateral homonymous hemianopia, amnesia, many odd phenoma
40
Signs/symptoms when the parietal lobe is affected
Hemisensory loss, reduced 2 point discrimination, agnosia, sensory inattention, Wernicke's dysphasia
41
Signs/symptoms when the occipital lobe is affected
Contralateral visual field defects, palinopsia, polyopia
42
Signs/symptoms when the cerebellum lobe is affected
**DANISH** **D**dysdiadochokinesis **A**taxia **N**ystagmus **I**ntension tremor (past pointing) **S**canning speech (dysarthria) **H**ypotonia, Hyporeflexia
43
Signs/symptoms when the cerebellopontine angle lobe is affected
Ipsilateral deafness, nystagmus, facial weakness and numbness, ipsilateral cerebellar signs
44
What are signs that might be present in someone with a brain tumour?
* **Papilloedema** * **CNVI/III palsy** * **Decreased GCS** * **Hemiparesis** * **Focal signs**
45
How would you investigate someone with suspected brain tumour?
* **CT** - usually initial investigation, may miss small lesions * **MRI** - particualrly valuable in posterior fossa tumours * **Tests to rule out extracranial primary source** - CT chest/abdo/pelvis, CXR, mammography, lymph node biopsy * **Biopsy**
46
What are the general priciples to management of a brain tumour?
* **Support** * **Corticosteroids** - (dexamethasone) cerebral oedema * **Anticonvulsants** - seizures (managed as focal seizures) * **Analgesia** * **Anti-emetics** * **Radiotherapy** - for gliomas and radiosensative metastases * **Chemotherapy** - temazolamide * **Endocrine replacement** - pituitary adenoma * **Surgery**
47
What is the average survival of glioblastoma multiforme?
Approximately 1 year
48
Difference between primary and secondary brain tumours
Primary = original lesion in brain. Usually one big lesion with less oedema. Secondary = many lesions, lesions small, oedema big. (Most common brain tumour - 15% of those with cancer get cerebral mets).
49
Commonest tumours that spread to brain
Breast, lung, malignant melanoma. | (Also GI tract, kidney)
50
Most common primary brain tumour in adults?
Glioblastoma multiforme
51
Most common brain tumour in children?
Astrocytoma - medulloblastoma
52
What is the most common pituitary tumour?
Adenoma, benign (Others inlcude prolactinoma, growth hormone secreting, non secreting)
53
Typical features in adenomas
Space occupying and endocrine effects: * Bitemporal hemianopia * Hypopituitarism * Hypersecretion of specific hormones * Acromegalu * Hyper-prolactinaemia * Cushing's
54
How high does prolactin have to be to suggest a prolactinoma?
\>4000
55
How are prolactinomas managed?
With dopaminergic antagonists, eg carbeorgoline
56
What is mannitol used
Rapid reduction of ICP. Arterial BP must be maintained to overcome icnreased ICP and maintain cerebral perfusion
57
Surgical managemnt of brain tumours
Surgical exploration, debulking or for biopsy Resection (especially for benign tumours eg meningioma) Pituitary adenoma - trans-sphenoidal surgery (hormone replacement) Hydrocephalus - intraventricular shunts
58
Prognosis of meningioma
Commonly cured by surgical excision, may require anticonvulsants
59
Prognosis of glioma/astrocytoma
Low grade - long life expectancy High grade - GBM, average 1 year life expectance
60
Prognosis of metastases
Frequently good medium term survivial
61
Prognosis of lymphoma
Poor survival (often \<1 year)
62
DDx brain tumour
Stroke Other intracranial mass - cerebral abscess, tuberculoma, subdural haematoma, intracranial haematoma Intracranial hypertension - presents as headache and papilloedema in young obese women, think this if mass but no mass present. Neuroimaging is normal but LP there is increased pressure Post-ictal (Todd's palsy) Venous thrombosis MS, Encephalitis
63
What is gerstmann's sundrome
Caused by left dominant parietal lobe lesion Presentation: Agraphia, acalculia, finger agnosia, left/right confusion
64
What is agraphia?
Writing disability
65
What is acalculia?
Lack of understanding of the rules for calculation
66
What is finger agnosia
Inability to identify fingers
67
What is left/right confusion?
Inability to distinguish right from left
68
What are paraneoplastic syndromes?
Paraneoplastic syndromes are symptoms that occur at sites distant from a tumor or its metastasis. These symptoms may be secondary to substances secreted by the tumor or may be a result of antibodies directed against tumors that cross-react with other tissue. The most common cancers associated with paraneoplastic syndromes include Lung carcinoma (most common) Renal cell carcinoma Hepatocellular carcinoma Leukemias Lymphomas Breast tumors Ovarian tumors Neural cancers Stomach cancers Pancreatic cancers