Pathology of brain tumours

Question 1

causes of raised ICP

Answer 1

Localised lesions like

1. Haemorrhage
2. Tumour
3. Abscess

Generalised pathology like
1. Oedema post trauma

Question 2

what are localised lesions/lesions in the head called? examples?

Answer 2

space occupying lesions

tumours
bleeding (haematoma)
abscess

Question 3

What are some effects of intracranial space occupying lesions? (2)

Answer 3

amount of tissue increases

raises ICP

cause an internal shift (herniation) between the intracranial spaces

Question 4

What can happen if there is an internal shift between intracranial spaces?

Answer 4

Cerebrum moves inferiorly over edge of tentorium (uncal herniation)

Cerebellum moves inferiorly into foramen magnum (coning)

Question 5

Name some types of brain herniation

Answer 5

Cingulate
central 
uncal - tentorial 
cerebellotonsillar - coning
upward
transcalvarial

Question 6

How does a subfalcine herniation affect the brain

Answer 6

brain is pushed away from tumour

the falx cerebri is pushed over to one side

the cingulate gyrus is pushed over to side and herniates under falx

lateral ventricle is crushed flat and displaced downwards

Question 7

How does a tentorial (uncal) herniation affect the brain

Answer 7

Brain herniates inferiorly at side of tentorium cerebelli

cerebral aqueduct is crushed and narrow

Question 8

What can cause brain stem death

Answer 8

cerebellar tonsillar herniation - tonsils move inwards and downwards and crush brainstem

Question 9

When tumours squeeze nearby tissue what can they cause?

Answer 9

local ischaemia

Question 10

squeeze on cortex and brainstem can cause which symptoms?

Answer 10

morning headaches

sickness

Question 11

squeeze on optic nerve can cause which symptoms

Answer 11

papilloedema - optic disc swelling

seen on fundoscopy

Question 12

As pressure increases it causes pupillary dilatation due to squeeze and stretch on which Cranial Nerve?

Answer 12

Cr N 3 - oculomotor

Question 13

As pressure increases: Glasgow coma scall falls due to…

Answer 13

squeeze on cortex and brainstem

Question 14

how can brain stem death result due to increased pressure

Answer 14

squeezing downwards of cerebellum into foramen magnum with crushing of brainstem

Question 15

Name 2 primary tumours of the brain residing in brain cells specifically

Answer 15

Glial - gliomas - glioblastoma, astrocytoma, oligodendroglioma (these are malignant tumours)

embryonic neural cells - medulloblastoma (childhood malignant tumour)

Question 16

Metastatic malignancy spreading to the brain

Answer 16

breast
lung
kidney
colon
melanoma

Question 17

Primary tumours in cells surrounding or originating outside the brain

Answer 17

arachnoidal cell - meningioma

nerve sheath cell - schwannoma, neurofibroma

pituitary gland - adenoma

lymphoid cell - lymphoma

capillary vessels - haemangioblastoma

Question 18

Site of nervous system tumours in adults

Answer 18

majority above tentorium

Question 19

Site of nervous system tumours in children

Answer 19

majority below tentorium

Question 20

What do gliomas look like?

Answer 20

they resemble cells of glial differentiation e.g astrocytes, oligodendrocytes and ependymal cells (all types of glial cells)

diffuse edges - not encapsulated

malignant but do not metastasise

Question 21

what are the 2 main types of astrocytoma called?

Answer 21

glioblastoma

low grade astrocytoma

(these examples are at extremes of differentiation)

Question 22

Describe what a glioblastoma is like

Answer 22

cellular, atypical tumour with necrosis under microscope

Question 23

Medulloblastoma (childhood malignant tumour)

Answer 23

tumour of primitive neuroectoderm (primitive neural cells)

sheets of small undifferentiated cells

children especially

posterior fossa, especially brainstem

Question 24

Meningioma

Answer 24

from arachnocytes - make up the coverings of the brain - the tumour attaches to the meninges. Can cause a depression in the cerebral hemisphere as a result

Small groups of cells whorl around each other, resembling an arachnoid granulation - sometimes calcification

benign - do not metastasise but can be locally aggressive and can invade the skull

slow growing, often resectable

Question 25

Nerve sheath tumours - where are they found? example?

Answer 25

found around peripheral nerves - intracranial and extracranial schwannoma is one example Normal schwann cells wrap around peripheral nerves and form electrical insulation

Question 26

what is 8th vestibulocochlear nerve schwannoma often called? what does it cause? where is it found?

Answer 26

Acoustic neuroma causes unilateral deafness found at angle between pons and cerebellum benign lesion but removal is technically difficult

Question 27

CNS lymphoma

Answer 27

High grade neoplasm Usually diffuse large B-cell lymphoma Often deep and central site in brain - Difficult to biopsy Difficult to treat as drug do not cross blood-brain barrier doesn't tend to spread outside CNS

Question 28

Haemangioblastoma

Answer 28

Space occupying tumour of blood vessels may bleed often found in cerebellum