Pathology of brain tumours

Question 1

what is needed for ICP to be stable

Answer 1

correct amount of brain tissue, blood, CSF

Question 2

what keep the brain in place within the skull

Answer 2

thick tough fibrous sheets

• Falx cerebri
• Tentorium cerebelli

Question 3

where does the spinal cord leave the skull

Answer 3

foramen magnum

Question 4

how can the brain move in relation to the falx and skull

Answer 4

cannot go through falx but can go around the edge

cannot go through the skull but can move down through the foramen magnum

Question 5

what can cause raised ICP

Answer 5

localised lesions

• haemorrhage (haematoma)
• tumour
• abscess

generalised pathology
- oedema post trauma

Question 6

what are localised lesions in the head known as

Answer 6

SOL - space occupying lesions

Question 7

how do SOL raise ICP

Answer 7

amount of tissue increases

causes internal shift (herniation) between intracranial spaces

Question 8

what are the 6 types of brain herniation

Answer 8

1. cingualate - cingulate gyrus pushed under falx, RL, LR
2. central - cerebrum pushed down
3. uncal - cerebrum moves inferiorly over edge of tentorium
4. cerebellotonsillar - tonsils move inwards and downwards and crush brainstem, down through foramen magnum
5. upward - cerebellum moves up
6. transcalvarial - out through skull fracture

Question 9

what herniation is the cause of brainstem death

Answer 9

cerebellotonsillar

Question 10

what herniation can narrow and crush the cerebral aqueduct

Answer 10

uncal

Question 11

what can swelling and shift lead to

Answer 11

local ischaemia

Question 12

what are the symptoms of squeeze on the cortex and brainstem

Answer 12

morning headache and sickness

Question 13

what are the symptoms of squeeze on the optic nerve

Answer 13

papilloedema - seen on fundoscopy

Question 14

what pressure causes pupillary dilation

Answer 14

squeeze and stretch on cranial nerve 3

Question 15

what pressure causes a fall in the GCS

Answer 15

squeeze on cortex and brainstem

Question 16

what pressure causes brainstem death

Answer 16

squeezing downwards of cerebellum into foramen magnum crushing of the brainstem

Question 17

what are the different groupings of intracranial tumours

Answer 17

CNS

• primary
• secondary (metastatic)

other intracranial
- cells originating outside the brain and spinal cord

Question 18

where do secondary metastatic brain tumours usually come from

Answer 18

breast, lung, kidney, colon, melanoma

Question 19

what are intracranial tumours that occur from brain cells (CNS tumours)

Answer 19

Glial cells – gliomas
MALIGNANT

Embryonic neural cells – medulloblastoma
CHILDHOOD MALIGNANT

Question 20

what are intracranial tumours that occur from cells surrounding or originating outside the brain

Answer 20

Arachnoidal cell – meningioma

Nerve sheath cell – Schwannoma, neurofibroma

Pituitary gland - adenoma

Lymphoid cell – lymphoma

Capillary vessels - haemangioblastoma

Question 21

where do CNS tumours most commonly occur in adults and children respectively

Answer 21

adults - above the tentorium

children - below the tentorium

Question 22

what are the characteristics of gliomas

Answer 22

resemble cells of glial differentiation

diffuse edges but NOT encapsulated

malignant but do NOT metastasise outside the CNS

Question 23

what are the three types of gliomas

Answer 23

Astrocytoma
- resemble astrocytes

Oligodendroglioma
- resemble oligodendrocytes

Ependymoma
- resemble ependymal cells

Question 24

what are the two main forms of astrocytoma

Answer 24

low grade astrocytoma

glioblastoma - most malignant

Question 25

how is low grade astrocytoma defined on microscopy

Answer 25

bland cells - similar to normal star shaped astrocytes small cell, small nucleus grow very slowly

Question 26

how is glioblastoma defined on microscopy

Answer 26

cellular, atypical tumour with necrosis large cell with multiple irregular nuclei grow quickly - often present with large tumours

Question 27

how is medulloblastoma defined on microscopy

Answer 27

from embryonic neural cells - sheets of small undifferentiated cells

Question 28

where are medulloblastoma usually found

Answer 28

posterior fossa, especially the brainstem children

Question 29

what are meningiomas

Answer 29

from arachnocytes - the cells that make the coverings of the brain benign and do NOT metastasise BUT can be locally aggressive and invade the skull

Question 30

how are meningioma defined on microscopy

Answer 30

bland cells forming small groups, sometimes with calcification slow growing often resectable

Question 31

what is schwannoma

Answer 31

a type of nerve sheath tumour normal schwann cells wrap around peripheral nerves and form electrical insulation

Question 32

what is an example of a schwannoma

Answer 32

8th vestibulocochlear nerve schwannoma = acoustic neruoma causes unilateral deafness benign lesion but technically difficult to remove found at the angle of the pons and cerebellum

Question 33

what is a pituitary adenoma

Answer 33

benign tumour in the pituitary fossa often secretes a pituitary hormone can impinge on the optic chiasma = visual signs

Question 34

what is CNS lymphoma

Answer 34

a high grade neoplasm often diffuse large B-cell lymphoma don't spread outside CNS

Question 35

why is CNS lymphoma difficult to biopsy and treat

Answer 35

biopsy - often deep and central in the brain treatment - drugs do not cross the blood brain barrier

Question 36

what is a haemangioblastoma

Answer 36

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

Question 37

what are some characteristics of secondary metastatic tumours

Answer 37

mostly carcinoma common histology = that of the primary tumour