Histopathology 18: Neuro-oncology Flashcards
List 4 genetic syndromes responsible for primary CNS tumours ?
Neurofibromatosis 1
Neurofibromatosis 2
Tuberous Sclerosis 1
Tuberous Sclerosis 2
Turbot’s syndrome
Outline the WHO grading of CNS tumours ?
Grade 1 : Benign, long-term survival
Grade 2 : causes death in > 5 years
Grade 3 : causes death in < 5 years
Grade 4 : causes death in < 1 year
NB Grade I and II are considered LOW grade
What type of tumours are the most common primary CNS tumours ?
Diffuse Gliomas (glial cells)
Give 2 examples of Glial tumours in adults ?
Astrocytoma
Oligodendrogliomas
NB diffuse = show a very infiltrative type of growth (become more malignant over time)
What’s the most common glial tumour in children ?
Pilocytic astrocytoma (NB this is a circumscribed glioma, not diffuse)
What are the typical histological features of Pilocytic Astrocytomas ? (2)
Piloid (hairy) cells
Rosenthal fibres
Which tumours do astrocytomas turn into after about 5-7 years ?
Glioblastomas
(It is a Grade 4 astrocytoma)
What mutation is most commonly seen in astrocytomas ?
IDH 1/2
Describe a typical feature of oligodendroglioma on histology ?
Fried eggs - Round cells with clear cytoplasm
Which genetic syndrome is associated with meningiomas ?
Neurofibromatosis 2
Where are medulloblastomas always found ?
cerebellum
List some symptoms of medulloblastoma ?
ICP symptoms- morning headaches, nause and vomiting, blurry vision
Loss of balance and coordination
Abnormal eye movements
NB cerebellum affected
List 3 typical features of medulloblastoma on histology ?
- Small blue round cells (hyperchromatic nuclei with NO cytoplasm)
- Homer-Wright rosettes
- Neuronal marker Synaptophysin positive
Where are metastatic brain tumours most commonly found ?
The grey-white junction (where grey and white matter meet)
- This is because the structure of the cerebral blood vessels change at this point (becoming smaller as they enter the white matter)
- Therefore, neoplastic emboli tend to get stuck at this level and then start growing
NB another site = meninges
A ventricular tumour presenting with hydrocephalus.
Most likely diagnosis ?
Ependymoma
A soft gelatinous, calcified tumour.
Most likely diagnosis ?
Oligodendroma
usual inheritance of CNS tumours
autosomal dominant
presentation of CNS tumours
- Intracranial Hypertension: headache, vomiting, change in mental state
- supratentorial = focal neurological deficit, seizures, personality changes
- subtentorial = cerebellar ataxia, long tract signs, cranial nerve palsy
what chemo is used in high grade gliomas
temozolamide
Tumour arising from Embryonal cells
medulloblastoma (2nd most common in children)
Most common genetic syndrome related to brain tumours
Neurofibromatosis
% of brain tumours due to genetics
<5%
Genetics in Diffuse gliomas
IDH 1/2 mutation
Genetics in Circumscribed Gliomas
MAPK pathway mutation (BRAF)
Pilocytic astrocytoma found in which condition and in which group of pts?
NF1 - CHILDREN
Astrocytoma location in brain
Often CEREBELLAR
Mutation in Pilocytic Astrocytoma
BRAF Mutation (KIAA1549-BRAF fusion)
Main site for Diffuse Astrocytoma
Cerebral hemispheres (see on MRI)
Most aggressive type of glioblastoma
de novo glioblastoma
Mutation in Diffuse Astrocytoma
Mutation in IDH1/2
Effect of IDH mutation in Glioblastoma Multiforme
PROTECTIVE
- IDH mutation is in astrocytoma, and 10% of glioblastoma arises from astrocytma (so secondary glioblastoma)
- So protective in that it is not as bad a primary glioblastoma (without IDH mutation) as this is FAR MORE aggressive
Name when glioblastoma spreads to other hemisphere
butterfly tumour
Type of necrosis that can be seen in Glioblastoma Multiforme
pallisadian necrosis
- there is necrosis surrounded by palisade tumour cells
most frequent brain tumour in adults
Metastatic carcinoma
most frequent brain tumour in children
Pilocytic astrocytoma
What does the tumour grade tell us?
Survival - important prognostic factor
24 y/o with long history of neurological signs (usually seizures). Which brain tumour?
Oligodendroglioma
- Those between 20-40 years
- get long history of neurological signs (usually seizures)
Mutation in almost 100% cases of Oligodendroglioma
Diagnostic mutation
IDH1/2 mutation
Co-deletion 1p/19q (NB this mutation has better prognosis if present)
Which has better prognosis, Oligodendroglioma or astrocytomas?
Oligodendroglioma (LESS aggressive and do not progress to a higher grade as quickly)
What is the major change in the last WHO (2016) CNS tumour classification?
Incorporation of genetic profile
Which mutation identifies the mutation diffuse astrocytic tumours with a better prognosis?
IDH mutation
Most common, and 2nd most common, primary intracranial tumours
- Most: gliomas
- 2nd: Meningioma
Where can you find Meningioma
anywhere in the craniospinal axis
Condition where you get multiple meningioma
NF2
Grade 2 meningioma is what?
When there is brain invasion
Mx of Meningiomas that are grade ≥ II
radiotherapy as well as surgery
Important aspect of determining grade of meningioma
Mitotic activity
- Grade is based on mitoses/ 10 high power fields
2nd most common tumour in kids
Medulloblastoma
Prognosis of different classifications of medulloblastomas
- WNT-activated – VERY GOOD prognosis (often cured with radio/chemotherapy)
- SHH-activated – Intermediate prognosis
- Non-WNT/non-SHH – VERY AGGRESSIVE, POOR prognosis
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