Neuropathology (2) Flashcards
What is the WHOs definition of cerebrovascular disease (stroke)?
3rd leading cause of death
Rapidly developing signs of focal disturbance of cerebral function, lasting more than 24 hours or leading to death with no apparent cause other than that of vascular origin
What is global anoxia?
loss of neurons in areas of vulnerability to anoxia-pattern seen in total circulatory collapse - hypoxix ischaemic changes in the brain
- incl neurones in cortex, hippocampus and purkinje cells of cerebellum
What is a watershed/boundary zone infarction?
infarction in cerebral cortex located at the boundaries between different arterial territories
- form of ischaemia - found with severe reduction in oxygen delivery to the brain e.g. severe hypotension in surgical/septic shock
What can cause infarction?
occlusion of artery-atherosclerosis
- risk factors = hypertension, smoking
Embolism - more common than thrombotic inclusion
- 1) atheroma in extracranial arteries e.g. bifurcation of carotid arteries, origin of vertebral arteries, ascending aorta and the arch of aorta
- 2) cardiac e.g. atrial fibrilliation, endocardititis
What are the general RF, local RF and secondary factors for intracerebral haemorrhage?
General = hypertension Local = aneurysm, arterio-venous malformation Secondary = amyloid angiopathy, tumour, trauma
What are the key sites of aneurysms for subarachnoid haemorrhages?
1) anterior communicating artery - 90%
2) internal carotid artery and middle cerebral artery
3) basilar artery
4) cerebellar artery
What does a tare of the middle meningeal artery cause?
epidural aneurysm - most common cause
How is the relative brain tumour distribution different between adults and children?
In adults brain tumours/CNS tumours are 14th whereas in children they are 2nd
What is the most common type of cerebral tumour?
glioblastoma and anaplastic astrocytoma - 35%
- glioblastoma is one of the most aggressive tumours with a survival expectancy of about 9 months
What is different about the latest version of classifying cerebral tumours?
important to incorporate molecular parameters into the classification
- genotype trumps the histological phenotype
For sites that lack any access to molecular diagnostic testing, a diagnostic designation of NOS
What are the molecular patterns that need to be determined for glial tumours?
isocitrate dehydrogenase - part of the kreb’s cycle - mutation in glioma improves prognosis but increases rate of epilepsy
Loss of heterozygosity at 1p and 19q
06 methylguaninemethyltransferase (MGMT) - Promoter methylation status
What is the WHO grading system for astrocytic tumours?
Grade 1: pilocytic astrocytoma (childhood)
Grade 2: diffuse astrocytoma
Grade 3: anaplastic astrocytoma
Grade 4: Glioblastoma
What are the common characteristics of diffuse astrocytomas?
most are isocitrate dehydrogenase (IDH) (1 or 2) mutant
usually have a good prognosis
occur in 20-40s
eventually transform to anaplastic astrocytoma then to secondary glioblastoma mutliforme (GBM) (40-50s)
Secondary GBM = glioblastoma and IDH mutant
Primary GBM = IDH wild type, older age
How are oligodendrogliomas classified?
regular branching capillary network on histological appearance
IDH mutation and 1p, 19q codeletion
What are the common sites for meningiomas?
parafalcine, lateral sulcus, orbito-frontal cortex, cerebellopontine angle, thoracic spinal dura, sites at base of skull
What are examples of peripheral nerve sheath tumours?
neurofibromatosis (type 1 and 2), neurofibroma (arise within nerve), schwannoma
What are the different groups of medulloblastomas classified by the WHO?
Group 1: WNT activated
Group 2: Sonic hedgehog activated
Group 3&4: non-WNT and non-SHH activated
Nmyc is also an important prognostic factor
What are examples of intradural, intramedullary spinal tumours?
within substance of SC - Astrocytoma, ependymoma
