Pathology of Brain Tumours

Question 1

What are the causes of raised intracranial pressure?

Answer 1

Localised lesions:
-Haemorrhage
-Tumour
-Abscess
Generalised pathology:
-Oedema post trauma

Question 2

What are the effects of intracranial space occupying lesions?

Answer 2

Amount of tissue increases
Raises intracranial pressure
Causes internal shift/herniation between the intracranial spaces

Question 3

Where can the brain herniate to as a result of intracranial space occupying lesions?

Answer 3

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

Question 4

How does swelling lead to ischaemia within the brain?

Answer 4

Tumours squeeze nearby tissue and cause local ischaemia

Question 5

What are the symptoms of pressure on the cortex and brainstem?

Answer 5

Morning headaches and sickness

Question 6

What are the symptoms of pressure on the optic nerve?

Answer 6

Papilloedema

Question 7

What signs are seen as intracranial pressure increases?

Answer 7

Pupillary dilation- squeeze and stretch on cranial nerve III
Falling GCS- squeeze on cortex and brainstem
Brain stem death- squeezing downwards of cerebellum into foramen magnum with crushing of brainstem

Question 8

What are tumours of the glial cells known as?

Answer 8

Gliomas

Question 9

What are tumours of the arachnoidal cells known as?

Answer 9

Meningioma

Question 10

What are tumours of the nerve sheath cell known as?

Answer 10

Shwannoma or neurofibroma

Question 11

What are tumours of the pituitary gland known as?

Answer 11

Pituitary gland adenomas

Question 12

When are CNS tumours more common above and below the tentorium?

Answer 12

Majority above tentorium in adults

Majority below tentorium in children

Question 13

What are the characteristics of a glioma?

Answer 13

Resemble cells of glial differentiation
Diffuse edges and not encapsulate
Malignant but do not metastasis outside the CNS

Question 14

What are the two main kinds of astrocytoma?

Answer 14

Low grade astrocytoma

Glioblastoma

Question 15

How are low grade astrocytomas characterised?

Answer 15

Bland cells on microscopy- similar to normal astrocytes

Grow very slowly

Question 16

What are the characteristics of a glioblastoma?

Answer 16

Cellular, atypical tumour with necrosis under microscope

Grow quickly and often present as large tumours

Question 17

What are the characteristics of a medulloblastoma?

Answer 17

Tumour of primitive neuroectoderm
Sheets of small undifferentiated cells
More common in children
Common in posterior fossa, especially the brainstem

Question 18

From what cells do meningiomas arise?

Answer 18

Arachnocytes

Question 19

What are the characteristics of a meningioma?

Answer 19

Slow growing
Often resectable
Benign but can be locally aggressive and invade skull
Microscopy- bland cells forming small groups that sometimes have calcification

Question 20

What are the characteristics of nerve sheath tumours?

Answer 20

Around peripheral nerves both intracranially and extracranially
Schwannoma is an example

Question 21

What kind of tumour is an acoustic neuroma and how would it present?

Answer 21

Schwannoma of the vestibulocochlear nerve
Unilateral deafness
Benign lesion but removal technically difficult

Question 22

What are the characteristics of a pituitary adenoma?

Answer 22

Benign tumour of the pituitary
Often secrete a pituitary hormone
Can grow superiorly and impinge on optic chiasma and give visual signs

Question 23

What are the characteristics of a CNS lymphoma?

Answer 23

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

Question 24

What are the characteristics of a haemangioblastoma?

Answer 24

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