Pathology of Brain Tumours

Question 1

What is meant by intracranial pressure?

Answer 1

The cranium is a hard, rigid, closed box and for pressure to be stable there must be (within certain limits) the correct amount of braintissure/blood/CSF

Question 2

There are thick tough fibrous sheets inside that keep the brain in place, what is A and what is B?

Answer 2

A - falx cerebri

B - tentorium cerebelli

Question 3

Can the brain go through the falx cerebri?

Answer 3

Brain cannot go through falx, but can go round edge

e.g. if pressurised

Question 4

Can the brain go through the skull?

Answer 4

Brain cannot go through skull, but can move down through foramen magnum

Question 5

What is the consistency of the brain like?

Answer 5

Brain is soft – like a jelly – so it can move easily

Question 6

What are the 2 main types of causes for raised intracranial pressure?

Answer 6

localised lesions

generalised pathology

Question 7

What are some examples of localised lesions that may be the cause of raised intracranial pressure?

Answer 7

Haemorrhage (if localised called a haematoma)

Tumour

Abscess

Question 8

What are some examples of generalised pathology that may be the cause of raised intracranial pressure?

Answer 8

Oedema post traums

Question 9

Localised lesions = __________________ in head = SOL

Answer 9

Localised lesions = Space Occupying Lesions in head = SOL

• Tumours
• Bleeding (haematoma)
• Abscess

Question 10

What are the effects of intracranial space occupying lesions? (SOL)

Answer 10

As the amount of tissue increases, intracranial pressure rises

Cause internal shift (herniation) between the intracranial spaces:

• Right-left or left-right
• Cerebrum moves inferiorly over edge of tentorium (uncal herniation)
• Cerebellum moves inferiorly into foramen magnum (coning)

Question 11

Image showing Tentorial (uncal) herniation

Answer 11

Question 12

Image showing Cerebellar tonsillar herniation

Answer 12

Crush important nuclei like respiratory and cardiac centres and you die

Question 13

What does swelling and shifting of brain tissue lead to?

Answer 13

Swelling and shift = localised ischaemia

Tumours squeeze nearby tissue and cause local ischaemia

Question 14

Pressur eon the brian has consequences, what are symptoms and signs seen?

Answer 14

squeeze on the cortex and brainstem = morning headaches and sickness - very important symptom

squeeze on the optic nerve = papilloedema (seen on fundoscopy of the eye)

Question 15

As pressure on the brain increases, what symtpoms may be seen?

Answer 15

Pupillary dilation - Squeeze and stretch on cranial nerve 3

Falling Glasgow coma scale - Squeeze on cortex and brainstem

Brain stem death – squeezing downwards of cerebellum into foramen magnum with crushing of brainstem

Question 16

What are different types of intracranial tumours?

Answer 16

Central nervous system:

• Primary tumours
• Secondary (metastatic tumours)

Other intracranial tumours:

• Cells originating outside brain and spinal cord (eg meningioma)

Question 17

What are the 2 different classifications of intracranial tumours?

Answer 17

Primary (benign and malignat)

Metastatic malignancy (rare in children)

Question 18

How are primary intracranial tumors named?

Answer 18

by resembelence of the cell of origin

Question 19

What is a tumour of glial cells called?

Answer 19

gliomas (glioblastoma, astrocytoma, oligodendroglioma, ependymoma)

Question 20

What is a tumour of embyronic neural calls called?

Answer 20

medulloblastoma

Nerve cell tumours are rare so tends to be embryonic neural cells as adults ones don’t change and divide and tend to be cell cycled block so only primitive neurons can form tumours

Question 21

What is a tumour of arachnoidal calls called?

Answer 21

meningioma

Question 22

What is a tumour of nerve sheath calls called?

Answer 22

Schwannoma, neurofibroma

Question 23

What is a tumour of the pituitary gland called?

Answer 23

adenoma

Question 24

What is the tumour of lymphoid cells called?

Answer 24

lymphoma

Question 25

What is a tumour of capillary vessels called?

Answer 25

haemangioblastoma

Question 26

Where may a intracranial metastatic malignancy originate from?

Answer 26

Breast, lung, kidney, colon, melanoma

Question 27

What are tumour of brain cells?

Answer 27

Glial cells – gliomas (glioblastoma, astrocytoma, oligodendroglioma, ependymoma) Embryonic neural cells – medulloblastoma

Question 28

What are tumours of cells surrounding or originate outside the brain?

Answer 28

Arachnoidal cell – meningioma Nerve sheath cell – Schwannoma, neurofibroma Pituitary gland - adenoma Lymphoid cell – lymphoma Capillary vessels - haemangioblastoma

Question 29

What are malignant intracranial tumours?

Answer 29

Glial cells – gliomas (glioblastoma, astrocytoma, oligodendroglioma, ependymoma)

Question 30

What are intracranial childhood malignant tumours?

Answer 30

Embryonic neural cells – medulloblastoma

Question 31

Where is the site of central nervous system tumours?

Answer 31

adults - majority run above tentorium children - majority below tentorium

Question 32

What do gliomas resemble?

Answer 32

Resemble cells of glial differentiation

Question 33

What are the structures of gliomas?

Answer 33

Diffuse edges – not encapsulated

Question 34

Are gliomas malignant and do they metastasise?

Answer 34

Malignant but do **_not_** metastasise outside the CNS Cannot get through the blood brain barrier

Question 35

Glioma - resemble cells of glial differentiation, whata re some exmaples?

Answer 35

Astrocytes = astrocytoma (including glioblastoma - very malignant type of astrocytoma) Oligodendrocytes = oligodendroglioma Ependymal cells = ependymoma

Question 36

What is an astrocyte?

Answer 36

astrocyte = 'star' shaped cell long processes support other cells structually and biochemically

Question 37

What are the 2 types of astrocytoma?

Answer 37

1. Low grade astrocytoma 2. Glioblastoma

Question 38

What is an astrocytoma – low grade?

Answer 38

Bland cells on microscopy (similar to normal astrocytes) Grow very slowly

Question 39

What is a glioblastoma?

Answer 39

most malignant astrocytoma (high grade on microscopy) = glioblastoma (sometimes called glioblastoma multiforme)

Question 40

What are glioblastoma cells like?

Answer 40

Cellular, atypical tumour, with necrosis under microscope Grow quickly - often present as large tumours

Question 41

What is a medulloblastoma?

Answer 41

Tumour of primitive neuroectoderm (primitive neural cells) Sheets of small undifferentiated cells Children especially effected Posterior fossa, especially brainstem

Question 42

What is a meningioma?

Answer 42

form "arachnocytes" - cells that make up the coverings of the brain They are slow growing and are often resectable

Question 43

Are meningiomas benign or metastatic?

Answer 43

“Benign” – do not metastasise – but can be locally aggressive and can invade the skull

Question 44

What do meningiomas look like on microscopy?

Answer 44

bland cells forming small groups, sometimes with calcification

Question 45

What are nerve sheath tumours?

Answer 45

Around peripheral nerves – intracranial and extracranial Schwannoma is one example Normal schwann cells wrap around peripheral nerves and form electrical insulation

Question 46

8th vestibulocochlear nerve schwannoma, often called ‘\_\_\_\_\_\_\_\_\_\_\_\_’ at angle between pons and cerebellum

Answer 46

8th vestibulocochlear nerve schwannoma, often called ‘**_Acoustic neuroma_**’ at angle between pons and cerebellum

Question 47

What is an acoustic neuroma?

Answer 47

8th vestibulocochlear nerve schwannoma at the angle between pons and cerebellum Causes unilateral deafness Benign lesion but removal technically difficult as often wedged right up against the brain stem and near lots of very important structures

Question 48

What is a pituitary adenoma?

Answer 48

Benign tumour of pituitary in pituitary fossa Often secrete a pituitary hormone Grow superiorly and impinge on optic chiasma – visual signs

Question 49

What are the signs of a pituitary adenoma?

Answer 49

Grow superiorly and impinge on optic chiasma – visual signs

Question 50

What is a CNS lymphoma?

Answer 50

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 Generally do not spread outside of CNS

Question 51

What is a haemangioblastoma?

Answer 51

tumour of blood vessels space occupying may bleed most often in cerebellum

Question 52

Are secondary tumours common or rare and what type of tumour are they commonly?

Answer 52

common mostly carcinomas

Question 53

What is the histology of secondary tumours like?

Answer 53

like the histology of the primary tumour