Pathology of Intracranial Tumours

Question 1

What are the anatomical considerations for ICP?

Answer 1

Falx cerebri and tentorium cerebelli
Foramen magnum

Question 2

What are some causes of raised intracranial pressure?

Answer 2

Localised lesions - haemorrhages, tumours and abscess
Generalised - oedema post trauma

Question 3

What are localised lesions?

Answer 3

Space occupying lesions in head - SOL
Tumours, haemorrhages and abscess

Question 4

What is the effects of intracranial space occupying lesions?

Answer 4

Amount of tissue increases and raises ICP
Causes internal shift (herniation) between intracranial spaces

Question 5

What is uncal herniation?

Answer 5

Cerebrum moves inferiorly over edge of tentorium

Question 6

What is coning?

Answer 6

Cerebellum moves inferiorly into foramen magnum

Question 7

What is a subfalcine herniation?

Answer 7

Under falx cerebri
There is a midline shift
Cingulate gyrus is pushed over to side and herniates underneath falx
Lateral ventricle is crushed flat and displaced downwards

Question 8

What does swelling and shift of brain tissue cause?

Answer 8

Localised ischaemia

Question 9

What are the symptoms and signs that there is pressure on brain?

Answer 9

Morning headaches and brainstem - squeeze on cortex and brainstem
Papilloedema - squeeze on optic nerve

Question 10

What happens if pressure continues to increase?

Answer 10

Pupillary dilation - CNIII is squeezed
Falling GCS - squeeze on cortex and brainstem
Brainstem death - squeezing down into foramen magnum

Question 11

Describe the classification of intracranial tumours

Answer 11

Primary - benign or malignant
Metastatic - breast, lung, kidney, colon and melanoma

Question 12

What are brain cell tumours?

Answer 12

Gliomas and medulloblastoma (embryonic neuronal cells)

Question 13

What are tumours from cells surrounding or originating outside the brain?

Answer 13

Meningioma, schwannoma, neurofibroma, adenoma, lymphoma, and hemangioblastoma

Question 14

What are malignant intracranial tumours?

Answer 14

Gliomas
Medulloblastoma - childhood malignant tumour

Question 15

What are the most common sites for CNS tumours?

Answer 15

Adult is above tentorium
Child is below

Question 16

Describe gliomas

Answer 16

Glial differentiation
Diffuse edges - not encapsulated
Malignant but does not metastasis outside of CNS
Can be from astrocytes, oligodendrocytes and ependymal cells

Question 17

Describe astrocytoma

Answer 17

Can be low grade or glioblastoma (2 extremes)
Astrocytoma grows very slowly and bland cells on microscopy
Glioblastoma is cellular, atypical and necrosis under microscope. Grows quickly

Question 18

Describe a medulloblastoma

Answer 18

Tumour of primitive neuroectoderm (primitive neural cells)
Sheets of small undifferentiated cells
Children esp.
Posterior fossa and esp. brainstem

Question 19

Describe a meningioma

Answer 19

From arachnocytes
Is benign so does not metastasis but can still be locally aggressive and can invade skull
Slow growing and often resectable

Question 20

What is meningioma like under microscopy?

Answer 20

Bland cells forming small groups sometimes with calcification
Calcification sometimes called a psammoma body

Question 21

Describe nerve sheath tumours

Answer 21

Around peripheral nerves - intracranial and extracranial
Schwannoma

Question 22

What is acoustic neuroma?

Answer 22

8th vestibulocochlear nerve schwannoma at angle between pons and cerebellum
Unilateral deafness and benign lesion
Removal is difficult

Question 23

Describe a pituitary adenoma

Answer 23

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

Question 24

Describe CNS lymphoma

Answer 24

High grade neoplasm
Usually diffuse large B cell lymphoma
Often deep and cortical site brain
Generally do not spread outside of CNS

Question 25

Describe hemangioblastoma

Answer 25

Tumour of blood vessels, space occupying, may bleed and most often in cerebellum

Question 26

Describe secondary tumours

Answer 26

Mostly carcinomas, common
Histology is that of primary tumours