CNS Tumours Flashcards
(36 cards)
How are CNS Tumours classified?
According to the presumed cell of origin.
Name the different types of cells of the CNS and the tumours they cause.
1.Glial cells-Astrocyomas,ependymoma,oligodendroglioma,glioblastoma
2.Primitive neuroectodermal cells-medulloblastoma,neuroblastoma
3.Nerve sheath cells-Schwannoma,Neurofibroma
4.Arachnoid cells-Meningioma
5.Lymporeticular cells-lymphoma
Examples of Extrinsic CNS Tumours
Meningiomas
neurofibromas
Schwannoma
Examples of Intrinsic CNS tumours.
1.Astrocytoma
2.Glioblastoma
3.Medulloblastoma
4.Oligondendrogliomas
5.Ependymomas
6.Choroid plexus papillomas
7.Hemangioblastoma
8.Lymphomas
9.Primitive neuroectodermal tumours.
Describe the ranking of CNS tumours in adults and children?
1.Adults-6th commonest
2.Children-2nd commonest
Why do CNS Tumours present with localising signs?
1.Tissue destruction
2.Non specific effects of raised intracranial pressure
Where are 70% of tumours in children situated?And what kind of tumours are most of them?
1.Posterior Cranial fossa
2.Intrinsic tumours
Where are 70% of tumours in adults situated?And what kind of tumours are most of them?
1.Supratentorially
2.Extrinsic and intrinsic both occur frequently.
What determines frequency of metastatic tumours?And what kind of tumours are most of them?
1.Age
2.Carcinomas
How do the metastatic tumours spread?
1.They form solid deposits in the CSF
2.Spread y speeding in the CSF
What does survival due to Metastatic tumours depend on?
Age,site,size and histology of the neoplasm
Pathogenesis of CNS tumour ?
Genetic
Chemical & viral
Radiation - ? Mobile phones
Immunosuppression – primary cns lymphomas
Trauma – role unproven
Describe the clinicopathological features of Brain tumours.
Brain tumors clinically present in two main ways;
Local effects – focal neurological signs eg epilepsy or paraplegia
Mass effects – non specific signs & symptoms of space occupying lesion ; herniation being the common cause of death
What perecentage of primary adult tumours do astrocytomas contribute to?
10%
Where do astrocytomas occur?
1.Children-cerebellum
2.Adults-Cerebral hemispheres
How are astrocytomas classified?
1.According to the predominant cell type and degree of differentiation
What does prognosis of Astrocytomas depend on?
1.Degree of differentiation
2.Age of pt
3.Site and size
What percentage of primary CNS tumours do glioblastomas contribute to?
30%
Where (in the brain) do glioblastomas occur?
In white matter of cerebral hemispheres.
How do glioblastomas arise/what are they due to?
De-differentiation from pre-existing astrocytomas
What does the prognosis of glioblastomas depend on?
Prognosis depends on similar features to astrocytomas
What is the commonest primitive neuroectodermal tumour?
Medulloblastoma
Where (in the brain) does a neuroectodermal tumour occur?
In cerebellum of children
Characteristics of Medulloblastomas?
Rapid growth with extensive infiltration,resluting in obstructive hydrocephalus.
CSF seeding is common.
