The Pathology of Intracranial Tumours Flashcards Preview

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Flashcards in The Pathology of Intracranial Tumours Deck (27)
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1
Q

Name four causes of raised intracranial pressure

A

Localised lesions:
• Haemorrhage (if localised called a haematoma)
• Tumour
• Abscess

Generalised pathology:
• Oedema post trauma

2
Q

What is a SOL?

A

Intracranial space occupying lesions (localised lesions)

3
Q

What are the effects of intracranial SOL?

A

• Amount of tissue increases
• Raises intracranial pressure
• Cause internal shift (herniation) between the intracranial spaces
- Right-left or left-right
- Cerebrum moves inferiorly over edge of tentorium (uncle herniation)
- Cerebellum moves inferiorly into foramen magnum (coning)

4
Q

Name six types of brain herniation

A
  • Cingulate - across falx cerebri
  • Central - middle downwards
  • Uncal - cortex through tentorium cerebelli
  • Cerebellotonsilar
  • Upward - push of brainstem down
  • Transcalvarial - through skull fracture to outside skull
5
Q

What is a subfalcine herniation?

A

Midline shift where brain is pushed away from tumour

6
Q

What are the anatomical changes that occur in a subfalcine herniation?

A
  • Falx 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
7
Q

What is a tectorial herniation?

A

Uncal herniation where the brain herniates inferiorly at side of tentorium –> aqueduct is crushed and narrow

8
Q

What happens in cerebellar tonsillar herniation?

A

Tonsils move inwards and downwards and crush the brainstem –> cause of brainstem death

9
Q

Give examples of symptoms and signs of localised pressure on the brain

A
  • Pressure on cortex and brainstem –> morning headaches and sickness
  • Pressure on optic nerve –> papilloedema (seems on fundoscopy of eye)
10
Q

What are the consequences of as intracranial pressure increases?

A
  • Pupillary dilation - squeeze and stretch on CN III
  • Falling Glasgow Coma Scale - pressure on cortex and brainstem
  • Brainstem death - pressure downwards of cerebellum into foramen magnum with crushing of brainstem
11
Q

What are the different types of intracranial tumours?

A
  • CNS: primary or secondary (metastatic) tumours

* Other: cells originating outside brain and spinal cord (i.e. meningioma)

12
Q

Give examples of primary (benign and malignant) intracranial tumours

A

Brain cells:
• Glial cells – gliomas (glioblastoma, astrocytoma)
• Embryonic neural cells – medulloblastoma

Cells surrounding or originating outside brain:
• Arachnoidal cell – meningioma
• Nerve sheath cell – Schwannoma
• Pituitary gland - adenoma
(• Lymphoid cell – lymphoma
• Capillary vessels - haemangioblastoma)
13
Q

Give examples of metastatic malignant intracranial tumours

A
  • Breast
  • Lung
  • Kidney
  • Colon
  • Melanoma
14
Q

How do the location of CNS tumour differ in children and in adults?

A
  • Adults: majority above tentorium

* Children: majority below tentorium

15
Q

Describe gliomas

A

Resemble cells of glial differentiation:
• Diffuse edges - not encapsulates
• Malignant but do not metastasise outside of CNS

16
Q

How do gliomas resemble cells of glial differentiation?

A
  • Astrocytes –> astrocytoma (including glioblastoma)
  • Oligodendrocytes –> oligodendroglioma
  • Ependymal cells –> ependymoma
17
Q

Describe an astrocyte

A

Star shaped cell - long processes support other cells structurally and biochemically

18
Q

What are two examples of astrocytomas?

A
  • Low grade astrocytoma
  • Glioblastoma (most malignant type)

(many others)

19
Q

Describe a glioblastoma

A
  • Cellular, atypical tumour, with necrosis under microscope

* Grow quickly - often present as large tumours

20
Q

What is a medullablastoma?

A

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

21
Q

Describe meningiomas

A

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
22
Q

Describe the microscopy of a meningioma

A

Shows bland cells forming small groups, sometime with calcifications (psammoma)

23
Q

What are nerve sheath tumours?

A
  • Around peripheral nerves - intracranial and extra cranial
  • Schwannoma is an example
  • Normal schwann cells wrap around peripheral nerve and form electrical insulation
24
Q

Give an example of a schwannoma and its effects

A

8th vestibulocochlear nerve schwannoma, often called ‘Acoustic neuroma’ at angle between pons and cerebellum
• Unilateral deafness
• Benign lesion but removal technically difficult

25
Q

Describe a pituitary adenoma

A
  • Benign tumour of pituitary in pituitary fossa
  • Often secrete a pituitary hormone
  • Grow superiorly and impinge on optic chiasma – visual signs
26
Q

What is a CNS lymphoma?

A
  • 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
27
Q

What is a haemangioblastoma?

A

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