brain tumours

Question 1

most common brain tumour

Answer 1

metastatic carcinoma

Question 2

what are the 2 things you need to figure out when you’re discussing brain tumour

Answer 2

intra-axial vs extra-axial
primary vs secondary

Question 3

describe types of glial cells and their tumours

Answer 3

atrocytes = maintain BBB
oligodendrocytes = meylin
ependymal cells = line ventricular system + central spinal canal
artocytomas, oligodendrogliomas, ependymomas

Question 4

presentation of brain tumour symptoms

Answer 4

headaches = inc ICP
focal neurological deficit
seizures

Question 5

describe astocytomas

Answer 5

80% adult primary brain tumours
CNS
4th - 6th decade

Question 6

macroscopic appearance of atrocytomas

Answer 6

diffuse = poorly edfined infiltrative tumour, expands, distorts surrounding brain
glioblastoma = variability in appearance throughout tumour, heam, necrosis (contrast enhancement), appear deceptively well-demarcated

Question 7

how do we grade astrocytoma

Answer 7

amen
atypia, mitoses, endothelial proliferation, necrosis
atypia alone = grade 2
with mitoses = grade 3
with necrosis/ endothelial proliferation = grade 4

Question 8

describe the histology of astrocytomas

Answer 8

moderate inc cellularity + variable degrees nuclear pleommorphism
anaplastic astrocytoma = additional features mitotic activity
glioblastoma = additional features nectorsis/vascular proliferation

Question 9

describe pseudopalisading necrosis

Answer 9

hypoxia -> migration -> necrosis + palisade -> angiogenesis + clonal selection

Question 10

describe diffuse astrocytoma

Answer 10

WHO grade 2
10-15% astrocytic brain tumours
peak incidence young adults 30-40
imaging = lack enhancement
differential diagnosis = distinction from reactive astrocytes

Question 11

what is gemistrocytic astrocytomyrs

Answer 11

20% tumour cells in diffuse astrocytoma
prone to progression to anaplasitc astrocytoma/GBM
considered WHO grade 2
surivial time = 6-8
length disease affected byr/prog to GBM = avg 4.5 urs
no predictor of when/whether prog is likely

Question 12

anaplastic astrocytoma

Answer 12

WHO grade 3
sample size in assessing mitotic activity, /multinucleated cells, abnormal mitoses
intermediate stage on way to GBM
strong tendency to progress within 2 yers

Question 13

glioblastoma

Answer 13

WHO grade 4
most frequent
45-75 yrs
cycstic necrosis, c/f cysts in low grade lesions
rapid growth + infiltration, necrosis/endo proliferation
rarely invades SAS/CSF
heam spread rare wo/surgery or invasion dura/bone

Question 14

primary glioblastoma

Answer 14

rapidly progressive, without pre-existing low grade tumour
older patients
amp EGFR gene, MDM2 overexpression, p16 deletion, PTEN mutation

Question 15

secondary glioblastoma

Answer 15

young patients w/previously diagnosed low grade astrocytic tumour

Question 16

glioblastoma invasion

Answer 16

invasive phemotype = early on invasion of white matter
- perineuronal satellitosis, perivasular growth, subpail spread
combo of migration + modulation of EC space
hard to cut out
distinct from invasion of carinomas into adj tissues

Question 17

how do glioblastomas affect ECM

Answer 17

distinct from invasion of carcinmas bc change nature ECM = mainly hyaluronic aci, except around bv & pial surface
cel-cell and cell-EC amtrix interactions
proteases degrade EC + remodel env to facilitate tumour growth
integrin rec interact w/mol in ECM -> locomotion

Question 18

describe oligodendrogliomas

Answer 18

5-15% gliomas
4th -> 5th decade
long history symptoms, seizures
cerebral hemispheres esp white matter

Question 19

morphology ofoligodendrogliomas

Answer 19

circumscribed, gelatinous massess
calcification common radiology
sheets fried egg cells w/ characteristic vascular pattern + calcification
low rate mitotic act
anaplastic + hybrid variants

Question 20

describe genetic of oligodendrogliomas

Answer 20

loss heterozygosity )LOH) of 1p + 19q
prognositc importance and response to chemo

Question 21

describe ependymomas

Answer 21

arise near ventricles + spinal canal
chilren = 4th ventricle
adults= spinal canal

Question 22

describe ependymomas morphology

Answer 22

solid papilllary mass arising from floor of centricle
round to oval nuclei, dense fibrillar background + rosette + perivascular pseudorosette formation
well differentiated + behaves as WHO grade II

Question 23

clinical features of ependymomas

Answer 23

posterior fossa ependymomas = hydrocephalus bc obstruction 4th ventricle
CS dissemination = common
avd survival 4 yrs