CNS Tumours

Question 1

How common are CNS tumours?

Answer 1

CNS tumours are the 16th most common tumours, making up 2% of all malignancies

Question 2

Which genetic conditions increase the risk of CNS tumours?

Answer 2

Neurofibromatosis types I and II

Question 3

What is the relationship between mobile phone use and CNS tumours?

Answer 3

There is a very weak link due to the heat generated by the mobile phone in close proximity to the brain. The further away from the head the phone is used, the less the risk

Question 4

Which age group are meningiomas most common in?

Answer 4

The elderly

Question 5

Which age group are benign astrocytomas most common in?

Answer 5

Children

Question 6

How common are CNS tumours in children?

Answer 6

They are the second most common malignancy after leukaemias and lymphomas

Question 7

Name some symptoms of CNS tumours in children

Answer 7

Seizures, headache, weakness, clumsiness, difficulty walking, fever, staring, persistent projectile vomiting with no obvious cause, squint, neck tilt, precocious puberty, growth retardation, vision problems, and irritability

Question 8

What are the red-flag symptoms for a headache caused by a space-occupying lesion, including a tumour?

Answer 8

Chronicity, no improvement with painkillers, worse at night and when lying down, pulsating nature, and a bifrontal, back of head, or throughout head location

Question 9

Which imaging modality shows fluid and oedema in the brain?

Answer 9

MRI (FLAIR)

Question 10

Why is MR spectroscopy useful in suspected CNS tumours?

Answer 10

It can identify biochemical markers for inflammation, normal brain, a slow-growing tumour, or an aggressive tumour. A marker for healthy brain is N-acetyl aspartase, found in neurons

Question 11

Name the three main neurosurgical interventions for CNS tumours

Answer 11

Stereotactic biopsy, open biopsy, and craniotomy and debulking

Question 12

Where do CNS tumours like to spread?

Answer 12

Along white matter tracts. CNS tumours rarely spread outside of the CNS

Question 13

Define the grading of CNS tumours

Answer 13

Grade I - benign
Grade II - relatively benign, often slow growing, but will eventually develop into grade III. Typically curable with aggressive resection
Grade III - relatively malignant, almost as aggressive as grade IV, death typically within 5 years
Grade IV - malignant, death typically within a year

Question 14

Name a genomic marker of glioma aggressiveness

Answer 14

ATRX loss with a TP53 mutation

Question 15

Name a genomic marker of oligodendrogliomas which are less aggressive

Answer 15

1p/19q co-deletion

Question 16

Name the four types of glioma

Answer 16

Astrocytomas, oligodendrogliomas, ependymomas, and mixed gliomas

Question 17

What is the most common glial tumour?

Answer 17

Glioblastoma - representing 54% of glial tumours

Question 18

Describe pilocytic astrocytomas

Answer 18

A benign, grade I tumour that commonly affects children

Question 19

Describe diffuse astrocytomas

Answer 19

A grade II tumour that tends to invade the surrounding tissues but grow very slowly. Can be fibrillary, gemistocytic, or protoplasmic

Question 20

Describe subependymal giant cell astrocytomas

Answer 20

A very rare grade II ventricular tumour associated with tuberous sclerosis. Can be cured with complete resection, but unfortunately is often difficult to fully resect

Question 21

Describe the typical presentation of a pilocytic astrocytoma

Answer 21

Vomiting, behavioural changes, nausea, headache, and drowsiness

Question 22

Which are of the brain do pilocytic astrocytomas usually occur in?

Answer 22

The cerebellum

Question 23

Describe the appearance of a diffuse astrocytoma on MRI

Answer 23

A dark spot that does not take up contrast, usually with unclear margins

Question 24

How do anaplastic astrocytomas usually present?

Answer 24

With a seizure, typically in a young adult

Question 25

What is the prognosis with an anaplastic astrocytoma?

Answer 25

Below 40% survival at 5 years with complete resection, chemotherapy, and radiotherapy

Question 26

How does glioblastoma multiforme usually present?

Answer 26

With seizures or focal neurological deficits - e.g. speech deficits if it involves Broca’s area - typically in an elderly patient

Question 27

What does glioblastoma multiforme look like on MRI?

Answer 27

A large mass with contrast uptake at the edges but a central cystic core, as the centre becomes thrombosed due to irregular angiogenesis

Question 28

Where do 50-60% of oligodendrogliomas occur?

Answer 28

Frontal lobes

Question 29

Which tumour has a ‘fried egg’ appearance on histology?

Answer 29

Oligodendroglioma. Grade III (high grade) oligodendrogliomas also show increased cellularity and neoangiogenesis

Question 30

Describe myxopapillary ependymomas

Answer 30

Grade I benign tumours which are slow-growing and typically affect the cauda equina of young adults

Question 31

Describe the appearance of an anaplastic ependymoma in microscopy

Answer 31

Hypercellularity and rosettes

Question 32

Why are medulloblastomas more common in children?

Answer 32

They are embryological tumours

Question 33

What is the most common site for a medulloblastoma?

Answer 33

The cerebellum

Question 34

What is the difference between adult and childhood medulloblastoma?

Answer 34

Childhood medulloblastoma is more common and usually occurs in the midline. Adult medulloblastoma is rare, but usually hemispheric

Question 35

What does a sonic hedgehog mutation in medulloblastoma indicate?

Answer 35

More aggressive prognosis

Question 36

Where do most meningiomas originate from?

Answer 36

Arachnoid cells

Question 37

What are the main symptoms of meningioma?

Answer 37

Seizures and anosmia (from nerve compression)

Question 38

What is the most common brain tumour?

Answer 38

Metastases

Question 39

Which five cancers most commonly metastasise to the brain?

Answer 39

Melanoma, lung adenocarcinoma, breast carcinoma, renal cancer, and colon cancer

Question 40

Why do melanomas like to metastasise to the brain?

Answer 40

They originate from the same germinal layer embryologically

Question 41

Define craniopharyngioma

Answer 41

A benign tumour of the pituitary gland which develops from a remnant of the pharyngeal branches from pituitary migration