primary CNS neplasms Flashcards
aetilogy f primary brain tumours
sporadic, unknown cause, due to sporadic mutations in key genes
sometimes: ionising radiation, immunodeficiency
some associated with genetic syndrome
why are brain tumours staged differently to other sites
they dont tend to metastasise
IDH mutant vs. wildtype
mutant has far better survivability
what is IDH
isocytrate dehydrgenase
diffuse glioma
two categories
- peadiatric type
- adult type
neoplasms of glial cells with a diffuse growth pattern (not well circumcised
paediatric type diffuse gliomas
low grade (rare) high grade - mostly mutations, more common, still relatively rare, all are WHO grade 4, por prognosis
adult type diffuse gliomas
mutatsions in isocitrate dehydrogenase are key drivers in lwer grade gliomas in adults and now are used to define this class of tumours either IDH mutant or IDH wild type
IDH mutant adult diffuse gliomas
slow and im some cases no prgression to higher grades
astrocytic differentiation if they acquire secnd mutations
if they carry translocation of chromosomes this leads to oligodentral differentiation and means better prognosis
IDH wild type adult diffuse gliomas
presence of different activating mutation
rapid prgression to grade 4 with relatively rapid acquisition of ther mutations
low grade IDH wild type doesnt meaningfully exist
grading of diffuse gliomas in adults
astrocytma, IDH mutant = grade 2-4
glioblastoma, IDH wildtype = grade 4
molecular testing is required to tell the difference between the two
location of astrocytomas and oligodendromas
any regins on the CNS, most commonly supretentorial, frontal lob/frontotemporal region more common site
presentation of astrocytomas and oligodendromas
gradually proggressive headache, subtle and progressive neurological abnormalities
memory/cognitive/speech/language/motor/sensory/persnality/behaviour
IDH wildtype tumours more likely to present with
seizures or collapse
low grade diffuse astrocytomas
6-9 years survival
usually supratentorial cerebral hemispheres
solid +/- cystic, diffuse - firm and tough, infiltrative, ill-defined, may crss midline via corpus collosum
grade 3 diffuse astrocytoma
2-3 years average survival
macroscopically no distinguishing features from grade 2
microscopically, more cellular, more nuclear atypia, mitotic activity
high grade astrocytoma/glioblastoma
15-20% of intracranial gliomas
peak incidence 45-55 years
very poor prognosis - rapidly fatal, especially if IDH wildtype, but treatment options can be effective (surgury + chemotherapy + radiotherapy)
macroscopic appearance of high grade astrocytoma/glioblastoma
large infiltrative tumur, necrosis, heterogenous appearance, cystic change, heamorrhage
histology if high grade astrocytoma/glioblastoma
astrocytic differentiation, pleomorphis, with areas of divergent differentiation in some cases, mitoses, vascular proliferation, necrosis
oligodendroglioma IHD mutant
have IDH mutatins
who grade 2 if conventional hitology
if high grade hstological features are present then grade 3
- young to middle aged
- insidious onset (presentation ooften with seizures)
- grow slowly
- preferentially involve superficial regions of cerebral hemispheres
prognosis is significantly better than for astrocytoma
average survival >10 years
combined 1p 19q deletions
strong predictor of response to chemotherapy and radiotherapy and overall survoval in both low and high grade ligodendrogliomas
definitional mutation: presence = oligodendroma
pilocystic astrocytoma
circumscribed asstrocytoma
children and young adults
10 year survival >95%, usually treated by surgery alone
piloid astrocytes (long hari like processes) that tend to result in formation of roosenthal fibres and oesinophilic granular bodies
meningioma
10-20% primary intracranial tumours also common around spinal cord
mean age late 50s
F:M 2:1
distribution parallels arachnoid villi
sequelae of meningioma
can compress brain/cord parenchyma; usually not brain invasive
may invade bone, sinuses, dura, cause reactive hyperostosis and/or bony erosion with invasion
meningioma histological features
whorls (groups of cells radiating from a central cluster) syncytial arrangements (cells fuse and cant see cell mambranes) bland ovoid nuclei nucelar psuedoinclusions
meningioma behaviour
there is grade 1-3, no grade 4
grading based on mitotic activity, presence of brain invasion and/or cellular anaplasia
recurrence- free + overall survival determined by a number of factors (histoloogical subtype, differentiation, resectability, brain invasion)
medulloblastoma
paediatric and adult
common in paediatric, rare in adults)
WHO grade 4 but better prognosis than paediatric WHO grade 4 astrcytoma as better response to treatment
primitive looking cells with neuroectodermal differentiation, may have nodular areas that are better differentiated
schwannoma
tumour of perineural cells around peripheral nerves
10% intracranial neoplasms
other cranial nerves, spinal - dorsal roots, peripheral nerves
firm, solid, sometimes cystic
WHO grade 1
accoustic neuroma
specific subtype of schwanoma
airises from VIII cranial nerve at cerebelloopontine angle that are usually solid, however are often bilateral in neurofibromatosis
