W21 - Neuro-oncology Flashcards
What are primary vs secondary CNS tumours?
Primary CNS tumours - tumours that originated within the CNS
Secondary CNS tumours - metastases from other cancers (10x more frequent than primary tumours in adults)
In the adult population, are primary or seconary CNS tumours more common?
Secondary (mets) are 10x more common than primary CNS tumours
3 S/S for each of the following:
- Intracranial hypertension
- Supratentorial mass
- Subtentorial mass
3 S/S for each of the following:
- Intracranial hypertension = headache, vomiting, change in mental status
- Supratentorial mass = focal neurological deficit, seizures, personality change
- Subtentorial mass = cerebellar ataxia, long tract signs, cranial nerve palsy
___ imaging is the most important in neuroimaging
MR imaging is the most important in neuroimaging
In terms of surgical intervention in CNS tumours, what 3 surgeries could be possible?
- Craniotomy for debulking - subtotal and complete resections (as much tumour as possible)
- Open biopsy - inoperable but approachable tumours (about 1cm), usually representative
- Stereotactic biopsy - if open biopsy not indicated, about 0.5cm tissue, tissue may be insufficient
WHO classification of tumours looks at what 3 tumour parameters?
- Tumour type
- Tumour grade
- Tumour molecular profile
CNS tumour type is typically defined by the ________________
putative cell of origin / line of differentiation
The most common primary CNS tumours are _____, which could arise from these 3 lineages - name them.
The most common primary CNS tumours are gliomas, which could arise from these 3 lineages:
1. Astrocytes
2. Oligodendrocytes
3. Ependyma
CNS tumours - the grading system is an attemp to stratify tumours based on what?
by outcome, i.e. low grade = long survival, high grade = short survival
NB:
grade 1 - benign = long-term survival
grade 2 = more than 5 years
grade 3 = less than 5 years
grade 4 = less than 1 year
Diffuse vs circumscribed gliomas - comment on each of their:
- grade
- epidemiology
- malignancy potential
Diffuse gliomas:
- grades 2 or higher
- epidemiology: adults, supratentorial
- malignancy potential = malignant progression
Circumscribed gliomas:
- grades 1-2
- epidemiology: children, often posterior fossa
- malignancy potential = rare
Diffuse vs circumscribed gliomas - comment on each of their genetic profiles
Diffuse gliomas: IDH1/2 muttions (30%), H2 mutations (1%)
Circumscribed gliomas: MAPK pathway mutations (i.e. BRAF)
The most common CNS tumour in 1st and 2nd decade of life is _______
The most common CNS tumour in 1st and 2nd decade of life is pilocystic astrocytoma (20% of CNS tumours below 14 yrs)
Pilocystic astrocytoma:
- where is it commonly found?
- MRI findings?
- Histology findings?
- Genetic profile?
Pilocystic astrocytoma:
- where is it commonly found = cerebellar
- MRI findings = well circumscribed, cystic, enhancing lesions
- Histology findings = piloid “hairy” cells, slow growing, low mitotic activity
- Genetic profile = BRAF mutations in 70%
Astrocytomas:
- Where is it normally found?
- Patient age?
- MRI findings?
- Histology findings?
- Genetic profile?
Astrocytomas:
- Where is it normally found = cerebral hemispheres (superficial, in white matter)
- Patient age = 20-40s
- MRI findings = T1 hypointense, T2 hyperintense, non-enhancing well-circumscribed lesion
- Histology findings = low-to-modrate cellularity, low mitotic activity
- Genetic profile = IDH1/2
Diffuse glioma:
- where is it commonly found?
- typical patient age?
- Genetic profile?
Diffuse glioma:
- where is it commonly found = supratentorial
- typical patient age = 20-40s
- Genetic profile = IDH mutants (imp becuse associated with good response to chemoradiotherapy)
Glioblastoma multiforme:
- median survival?
- typical patient age?
- where is it most commonly found?
- MRI findings?
- Histology findings?
- IDH status?
Glioblastoma multiforme:
- median survival = 8 months
- typical patient age = >50
- where is it most commonly found = cerebral hemispheres
- MRI findings = heterogenous (due to necrosis/haemorrhage), enhancing post-contrast
- Histology findings = high cellularity, high mitotic activity, necrosis
- IDH1 WT normally (hence why they dont respond well to therapy
Meningiomas:
- % of primary CNS tumours?
- typical age of presentation?
- MRI findings?
Meningiomas:
- % of primary CNS tumours = 38%
- typical age of presentation = rare <40, incidence goes up with age
- MRI findings = extra-axial, isodense, well-demarcated masses typically with cleft between tumour and brain
In meningiomas, the grading is based on a combination of morphological tests, 2 of which are very imp - name them.
- Mitotic activity
- Microscopic brain invasion
(although these tumours are axial, sometimes they grow into the brain tissue so careful histo is imp)
What does this MRI of the brain show?
Lots of metstases
