Pathology of Brain Tumours

Question 1

Flow always occurs down

Answer 1

a pressure gradient

Question 2

Equation for cerebral perfusion pressure

Answer 2

CPP = MAP - ICP

Question 3

Equation for cerebral blood flow

Answer 3

CBF = CPP/CVR
or
CBF = (MAP - ICP) / CVR

(CVR = cerebrovascular resistance)

Question 4

Ischaemia causing raised ICP will result in

Answer 4

increased MAP, to ensure CPP is maintained

Question 5

What happens at a CPP < 50 mmHg?

Answer 5

Brain cannot be perfused adequately with oxygen and nutrients which results in loss of function

Question 6

What happens at a CPP > 150 mmHg?

Answer 6

Loss of control of blood flow causing ischaemic forced vasodilation and brain oedema, which results in ICP and MAP becoming equal - no blood flow

Question 7

Examples of causes of raised ICP

Answer 7

Inflammation e.g. menignitis, encephalitis, abscess
Vascular e.g. intracranial haemorrhage, brain swelling
Tumours
Hydrocephalus

Question 8

Effects of intracranial space occupying lesions

Answer 8

Amount of tissue increases
Raised ICP puts CBF at risk
Can cause herniation between the intracranial spaces if focal

Question 9

What are the thick, fibrous sheets inside the cranium that keep the brain in place?

Answer 9

Falx cerebri
Tentorium cerebelli
Dura mater

Question 10

What are the openings around the fibrous sheets inside the cranium?

Answer 10

Subfalcine space
Tentorial hiatus
Foramen magnum

Question 11

A focal lesion/mass can cause

Answer 11

internal shift between the intracranial spaces

Question 12

In what direction might the cerebrum herniate?

Answer 12

Inferiorly via the tentorium

Question 13

In what direction might the cerebellum herniate?

Answer 13

Inferiorly via foramen magnum

Question 14

What percentage of brain tumours are primary tumours in adults?

Answer 14

65%

Question 15

How are brain tumours classified?

Answer 15

By their resemblance to their cell of origin

Question 16

Examples of glial cell tumours

Answer 16

Glioblastoma
Astrocytoma
Oligodendroglioma
Ependymoma

Question 17

Examples of primitive neuroectoderm tumours

Answer 17

Medullablastoma

Question 18

Examples of arachnoidal cell tumours

Answer 18

Meningioma

Question 19

Examples of nerve sheath cell tumours

Answer 19

Schwannoma

Neurofibroma

Question 20

Examples of pituitary gland tumours

Answer 20

Adenoma

Question 21

Examples of lymphoid cell tumours

Answer 21

Lymphoma

Question 22

Examples of capillary tumours

Answer 22

Haemangioblastoma

Question 23

Where are secondary tumours in the brain commonly metastasised from?

Answer 23

Breast
Lung 
Kidney 
Colon 
Melanoma

Question 24

Features of ischaemic penumbra

Answer 24

Local ischaemia of brain tissue surrounding a tumour

Local loss of function

Question 25

Features of glioma

Answer 25

CNS supporting cells Diffuse edges Don't metastasise outside of the CNS

Question 26

What is the highest grade of astrocytoma termed?

Answer 26

Glioblastoma, worst prognosis

Question 27

Why is the prognosis of glioblastoma poor?

Answer 27

Grows rapidly and responds poorly to surgery

Question 28

Features of medulloblastoma

Answer 28

Small, blue, round-cell tumour Found mainly in children Occur in posterior fossa, especially in brainstem Poor prognosis

Question 29

Features of meningioma

Answer 29

From arachnocytes Connective tissue tumours Benign Won't metastasise but can be locally aggressive and invade the skull

Question 30

Features of nerve sheath tumours

Answer 30

Occur around the nerves May be seen in CNS and PNS Acoustic neuroma most common - causes unilateral deafness Benign lesion but difficult to remove surgically Can cause contralateral cranial nerve damage

Question 31

Features of pituitary adenoma

Answer 31

Benign tumour of posterior pituitary in pituitary fossa Often secrete pituitary hormone Many are non-functional Cause panhypopituitarism May result in acromegaly/gigantism due to growth hormone secretion Grow superiorly and impinge on optic chiasma

Question 32

Features of CNS lymphoma

Answer 32

``` High grade neoplasm Usually diffuse large B-cell lymphoma Often occur at deep and central sites Difficult to treat - drugs don't cross blood-brain barrier Generally don't spread outside CNS ```

Question 33

Features of capillary haemangioma

Answer 33

Space occupying May bleed Most common in cerebellar hemispheres

Question 34

Features of secondary brain tumours

Answer 34

Mostly carcinomas Common metastases Usually present with focal signs Some can be removed surgically but dependent on site Tend to be encapsulated and surrounded by oedema