AP: CNS Neoplasms 1 & 2

Question 1

What are trasncalvarial herniations?

Answer 1

Brain herniating out through defect (skull defect, traumatic, surgical).

Question 2

What are three causes of communicating hydrocephalus (obstruction of CSF pathway in subarachnoid space)?

Answer 2

• Inflammation (meningitis)
• Haemorrhage (subarachnoid haemorrhage)
• Tumour within the subarachnoid space (meningeal carcinomatosis)

Question 3

What are some causes of non-communicating hydrocephalus (obstruction to CSF pathways within ventricular system)?

Answer 3

• Congenital malformations.
• Inflammatory processes.
• Tumours.
• Haemorrhage.

Question 4

What are common sites of obstruction in non-commouncating hydrocephalus?

Answer 4

• Foramen of Monro (interventricular foramen)
• Aqueduct of Sylvius (cerebral aqueduct)
• Exit foramina of the fourth ventricle

Question 5

How is cerebral oedema classified?

Answer 5

1. Vasogenic
2. Cytotoxic
3. Interstitial/hydrocephalic

Question 6

What is vasogenic cerebral oedema?

Answer 6

Most common type - results from increased permeability of endothelium of the cerebral vasculature, which forms the blood brain barrier.

Question 7

What is cytotoxic cerebral oedema?

Answer 7

• Excessive amounts of water entering one or more cellular populations (because of changes at cellular level).
• Results from injury impairing cellular capacity to maintain ionic haemostasis.

Question 8

What is interstitial cerebral oedema?

Answer 8

• The accumulation of CSF in extracellular spaces and periventricular white matter.
• CSF collects in obstructed ventricles.
• Pressure increased, CSF forced across ependymal linings into extracellular glial tissue spaces.

Question 9

How are CNS tumours classified?

Answer 9

• Primary neoplasm.
• Secondary or metastatic neoplasm.
• Pseudoneoplastic lesion.

Question 10

What are the two different growth patterns considered in primary neoplasms?:

• _____ vs _____.
• _____ vs _____.

Answer 10

• Compression vs. infiltration.
• Diffuse vs. circumscribed gliomas.

Question 11

What are the clinical effects of CNS neoplasms?

Answer 11

Localised:

• Loss of function/neurological deficits
• Inappropriate excitation/seizures

Generalised:

• Raised ICP

Question 12

What is the function of oligodendrocytes?

Answer 12

Make and maintain myelin

Question 13

What were the 4 grades under the WHO grading scale?

Answer 13

WHO Grade 1:

• low proliferative potential
• potential for cure with resection

WHO Grade 2:

• tendency to progress with recurrence
• survival >5 years

WHO Grade 3:

• post operative adjuvant treatment
• survival 2-3 years

WHO Grade 4:

• malignant microscopy
• rapid pre- and post- evolution, fatal

Question 14

Where are gliomas normally found across the lifespan?

Answer 14

Kids: brainstem, cerebellum and midbrain

Adults: cortex, spinal cord

Question 15

What is an astrocytoma?

Answer 15

Diffuse astrocytoma = morphological and biological continuum ranging from well differentiated to highly anaplastic lesion.

Question 16

What are 2 possible signs of Grade IV Astrocytoma (Glioblastoma)?

Answer 16

• Necrosis and/or
• Endothelial proliferation (piling up of cells in vascular tube).

Question 17

What proportion of glioblastomas are primary/secondary, and what gene variations are they related to?

Answer 17

• Primary 90-95%, Older
  
  • EGFR amp
  • PTEN deletion
• Secondary 5-10%, Younger
  
  • p53 mutation
  • IDH mutation

Question 18

What is glioblastoma multiforme? (5 points)

Answer 18

• White matter of hemispheres
• Variegated
• Haemorrhage
• Necrosis
• Thrombosed vessels

Question 19

What is an independent prognostic factor for anaplastic gliomas and glioblastomas?

Answer 19

IDH1 and IDH2

Question 20

MENINGIOMAS

• Where are they most often derived from?
• Desribe their growth pattern.
• Circumscribed: Y/N?

Answer 20

• Almost invariably derived from dura.
• Grow locally and tend to be circumscribed.
• Some will invade, but push the brain.

Question 21

What are stereotypic features of meningioma?

Answer 21

Behaviour is highly variable

• Whorls
• Syncytial arrangements
• Nuclear pseudoinclusions
• Psammoma bodies
• Stromal calcification

Question 22

What is a schwannoma/neurilemmoma?

Answer 22

Benign peripheral nerve sheath tumour that classically involve the acoustic cranial nerve

Question 23

What proportion of CNS tumours do metastases make up? Where do they commonly come from?

Answer 23

20-25%

Lung, Breast, Melanoma, Renal, GIT

Question 24

What is a pituitary adenoma?

Answer 24

• 10-15% intracranial neoplasms.
• Have a mass effect.
• Apoplexy, haemorrhage.
• Peptide production (GH, ACTH, Prolactin, TSH etc).
• Pituitary deficiencies.