The Pathology of intracranial tumours

Question 1

what is meant by intracranial pressure?

Answer 1

Cranium is a hard, rigid, closed box

For pressure to be stable must be (within certain limits) correct amount of brain tissue/blood/CSF

Question 2

what must be considered anatomically in relation to intr cranial pressure?

Answer 2

There are thick tough fibrous sheets inside that keep the brain in place
Falx cerebri
Tentorium cerebelli

Opening to spinal cord
Foramen magnum

Question 3

can brain go through the falx cerebri?

Answer 3

Brain cannot go through falx, but can go round edge

Question 4

can brain go through the skull?

Answer 4

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

Question 5

what are localised lesion causes of raised intra-cranial pressure?

Answer 5

Haemorrhage (if localised called a haematoma)
Tumour
Abscess

Question 6

what are generalised pathologies causing raised intra-cranial pressure?

Answer 6

Oedema post trauma

Question 7

what are space occupying lesions in the head?

Answer 7

Tumours
Bleeding (haematoma)
Abscess

Question 8

what effect do space occupying lesions have in the cranium?

Answer 8

Amount of tissue increases
Raises intra cranial pressure
Cause internal shift (herniation) between the intracranial spaces

Question 9

how can the brain internally shift?

Answer 9

Right-left or left-right

Cerebrum moves inferiorly over edge of tentorium (uncal herniation)

Cerebellum moves inferiorly into foramen magnum (coning)

Question 10

what is tentorial herniation?

Answer 10

Uncal herniation of temporal lobe over the tentorium

Question 11

what is coning?

Answer 11

Cerebellotonsillar (‘tonsillar’) herniation of brain stem through foramen magnum

Question 12

Subfalcine (= under falx) herniation =

Answer 12

midline shift

Falx (falcine membrane) pushed over to side

Cingulate gyrus is pushed over to side and herniates underneath falx = subfalcine herniation

Lateral ventricle is crushed flat and displaced downwards

Question 13

what effect does swelling and shift have?

Answer 13

localised ischaemia
Tumours squeeze nearby tissue and cause local ischaemia

Question 14

what symptoms and signs does squeeze on cortex and brainstem have?

Answer 14

morning headaches and sickness

Question 15

what symptoms and signs does squeeze on optic nerve have?

Answer 15

papilloedema (seen on fundoscopy of eye)

Question 16

as intra cranial pressure increases what signs can be seen?

Answer 16

Pupillary dilation
Falling Glasgow coma scale
Brain stem death

Question 17

what is pupillary dilation caused by?

Answer 17

Squeeze and stretch on cranial nerve 3

Question 18

what is a falling glasgow coma scale caused by?

Answer 18

Squeeze on cortex and brainstem

Question 19

what is brain stem death caused by?

Answer 19

squeezing downwards of cerebellum into foramen magnum with crushing of brainstem (patient is dead)

Question 20

what types of intracranial tumours are within the CNS?

Answer 20

Primary tumours
Secondary (metastatic tumours)

Question 21

what intracranial tumours are not found within the CNS?

Answer 21

Cells originating outside brain and spinal cord (eg meningioma)

Question 22

what are different types of primary intracranial tumours (benign and malignant)?

Answer 22

Glial cells – gliomas (glioblastoma, astrocytoma, oligodendroglioma, ependymoma)
Embryonic neural cells – medulloblastoma
Arachnoidal cell – meningioma
Nerve sheath cell – Schwannoma, neurofibroma
Pituitary gland - adenoma
Lymphoid cell – lymphoma
Capillary vessels - haemangioblastoma

Question 23

glial cells

Answer 23

gliomas (glioblastoma, astrocytoma, oligodendroglioma, ependymoma)

Question 24

embryonic neural cells

Answer 24

medulloblastoma

Question 25

arachnoudal cells

Answer 25

meningioma

Question 26

Nerve sheath cell

Answer 26

Schwannoma, neurofibroma

Question 27

Pituitary gland

Answer 27

adenoma

Question 28

lymphoid cell

Answer 28

lymphoma

Question 29

Capillary vessels

Answer 29

haemangioblastoma

Question 30

what type of malignancy is common in adults but rare in children?

Answer 30

Metastatic malignancy Breast, lung, kidney, colon, melanoma

Question 31

which primary tumours are originated from brain cells?

Answer 31

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

Question 32

which primary tumours are originated from cells surrounding / outside the brain?

Answer 32

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

Question 33

which primary tumours are classed as malignant tumours?

Answer 33

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

Question 34

which primary tumour is a type of childhood malignant tumour?

Answer 34

Embryonic neural cells – medulloblastoma

Question 35

what is the location of CNS tumours in adults commonly?

Answer 35

Majority above tentorium

Question 36

what is the location of CNS tumours in children commonly?

Answer 36

Majority below tentorium

Question 37

how would you describe the diffuse edges of gliomas?

Answer 37

not encapsulated

Question 38

how is the malignancy of gliomas described metastasise wise?

Answer 38

Malignant but do not metastasise outside the CNS

Question 39

glial cells differentiate into...

Answer 39

astrocytoma

Question 40

oligodendrocytes differentiate into...

Answer 40

oligodendroglioma

Question 41

ependymal cells differentiate into...

Answer 41

ependymoma

Question 42

what are the different tyoes of gliomas?

Answer 42

Astrocytoma (main type)

Question 43

how is the shape of an astrocyte described?

Answer 43

‘Star’ shaped cell Long processes support other cells structurally and biochemically

Question 44

what are the different types of extremes of astrocytoma?

Answer 44

Low grade astrocytoma Glioblastoma [3. Many others........]

Question 45

how are cells on microscopy described in low grade astrocytoma?

Answer 45

Bland cells on microscopy (similar to normal astrocytes) Grow very slowly small cells with single nucleus

Question 46

how are cells on microscopy described in high grade astrocytoma

Answer 46

glioblastoma large tumour with necrosis

Question 47

what is a gliobastoma?

Answer 47

Cellular, atypical tumour, with necrosis under microscope Grow quickly – often present as large tumours Large cell with multiple nuclei / single nucleus

Question 48

what is medulloblastoma?

Answer 48

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

Question 49

what is meningioma?

Answer 49

From “arachnocytes” – cells that make up the coverings of the brain “Benign” – do not metastasise – but can be locally aggressive and can invade the skull slow growing / often resectable

Question 50

what is the location of meningioma most commonly?

Answer 50

Meningioma is usually attached to the meninges and pushes into the brain but does not usually invade it

Question 51

what does microscopy of a meningioma show?

Answer 51

Microscopy – bland cells forming small groups, sometimes with calcification Small groups of cells whorl around each other, resembling an arachnoid granulation The calcification is sometimes called a psammomabody (from ‘grain of sand’)

Question 52

what are nerve sheath tumours?

Answer 52

Around peripheral nerves – intracranial and extracranial

Question 53

what is an example of a nerve sheath tumour?

Answer 53

Schwannoma

Question 54

how do normal schwann cells present?

Answer 54

Normal schwann cells wrap around peripheral nerves and form electrical insulation

Question 55

what is 8th vestibulocochlear nerve schwannoma known as?

Answer 55

‘Acoustic neuroma’ at angle between pons and cerebellum

Question 56

what are symptoms of acoustic neuroma?

Answer 56

Unilateral deafness Benign lesion but removal technically difficult

Question 57

how is a pituitary adenoma described?

Answer 57

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

Question 58

what is a CNS lymphoma?

Answer 58

High grade neoplasm Usually diffuse large B-cell lymphoma Often deep and central site in brain Difficult to biopsy Generally do not spread outside of CNS

Question 59

what is a haemangioblastoma?

Answer 59

Tumour of blood vessels Space occupying May bleed Most often in cerebellum

Question 60

how are secondary tumours described?

Answer 60

Mostly carcinomas Common Histology = that of the primary tumour