Histopath - Neuro Flashcards
Only known environmental risk factor for CNS cancer
Previous radiotherapy to head and neck
Supratentorial tumour clinical features
Seizures
personality change
focal neuro deficit
Subtentorial tumour clinical features
Cerebellar signs
Long tract signs - hyperreflexia?
CN palsies
Craniotomy - indication, purpose
Debulking
Subtotal & complete resections
Remove as much tumour as (safely) possible
Open biopsy - indications, purpose
Inoperable but approachable tumours (~1cm)
Take sample - usually representative
Stereotactic biopsy - indications, purpose
If open biopsy not indicated, ~0.5cm tissue
Tissue may be insufficient
What components are assessed to give tumour grade
Proliferative activity
Cell differentiation
Necrosis
Genetic profile
Grading of CNS tumour
Grade 1 = benign
Grade 2 = >5 years
Grade 3 = <5 years
Grade 4 = <1 year
Diffuse gliomas - management
complete resection impossible due to direction of growth into CNS parenchyma
Genetics of diffuse gliomas
Often have IDH1/2 mutations H3 mutations (1%)
Genetics of circumscribed gliomas
> 90% have MAPK pathway mutations
- BRAF
- NF1
- FGFR1
Most common tumour of children
Pilocytic astrocytoma (WHO grade 1)
Imaging: ‘well circumscribed cystic enhancing lesion’
What is it?
Pilocytic astrocytoma
Histology of pilocytic astrocyoma
Piloid ‘hairy’ cell
Rosenthal fibres
Low mitotic activity
Histology of astrocytoma
Low-moderate cellularity
Low mitotic activity
No vascular proliferation, necrosis
Most common glial cell tumour (glioma)
Glioblastoma
also most aggressive
Histology of glioblastoma
High cellularity
High mitotic activity
Micro vascular proliferation (neoangiogenesis)
Necrosis
MRI reports ‘extra-axial, isodense, contrast-enhancing’
What is it?
Meningioma
Histology of meningioma
Psammoma bodies
Calcifications
Most frequent CNS tumour in adults?
Metastases
Most frequent primaries that metastasise to CNS
Breast
Lung
Melanoma
Renal
Histology of Medulloblastoma
Homer-Wright rosettes
4 subtypes:
- classic
- nodular / desmoplastic
- extensive nodularity
- large cell anaplastic
Grade of medulloblastoma
All WHO grade 4
Usual site of diffuse glioma
Supratentorial
Usual site of circumscribed glioma
Posterior fossa
Usual site of pilocytic astrocytoma (type of circumscribed glioma)
Cerebellar
Optic-hypothalamic
Brain stem
Usual site of astrocytoma (diffuse glioma)
Cerebral hemispheres
Subfalcine herniation
Singular cortex pushed under falx
Rare
Not acute
Transtentorial (uncal) herniation
Raised ICP supratentorially
Medial temporal lobe pushed into posterior cranial fossa
Tonsillar herniation
Global raised ICP
Cerebellum pushed through base of skull
Can cause cardio respiratory depression (via compression of brain stem)
TIA future risk
1/3 of those with TIA get significant infarct within 5 years
Non-traumatic intra-parenchymal haemorrhage - cause & location of bleed
HTN in majority of bleeds
Small intraparenchymal vessel rupture
Sub cortical region most common - esp basal ganglia
Subarachnoid haemorrhage - cause & location of bleed
Rupture of Berry aneurysm
80% internal carotid artery bifurcation
20% within vertebro-basilar circulation
Most common cause of stroke
Infarction - tissue death due to ischaemia (70-80%)
Common sites of cerebral atherosclerosis
Carotid bifurcation
Basilar artery
Most common site of embolic occlusion (causing stroke)
Middle of cerebral artery branches
Origin of emboli causing stroke?
Heart
Other atherosclerotic plaques
Signs of basal skull fracture
Otorrhoea, rhinorrhoea
Battle sign (mastoid bruising)
Periorbital bruising + swelling (Raccoon eyes)
Contusion definition
Brain in collision with skull causing surface bruising
If Pia mater is torn –> ‘laceration’
Areas of brains susceptible to contusion
Lateral surfaces of hemisphere
Inferior surfaces of frontal & temporal lobes
Commonest cause of coma (when no bleed present)
Diffuse axonal injury
Chronic Traumatic encephalopathy
Psych presentations in retired American footballers (emerging in rugby + football)
Tau pathology
Histology of Prion disease
Prion protein deposits
Spongiform change
Pathological protein plaques in cerebellum
Clinical features new Variant CJD
Patients <45 yrs old
Cerebellar ataxia
Dementia
Longer duration than CJD
Histology of Alzheimer’s
Extracellular amyloid plaques
Neurofibrillary Tau tangles
+ same protein from plaques builds in vessels ‘cerebral amyloid angiopathy’
Macroscopic changes in Alzheimer’s
Cerebral atrophy
Large ventricles
Severe shrinkage of hippocampus
Widening of sulci, thinning of gyri
Braak staging of Alzheimer’s
I-III = medial temporal lobes
IV = wider spread throughout temporal lobes
V = peristriate cortex
VI = primary visual cortex
What Braak stage are Alzheimer’s patients with Sx
stage III-IV
Macroscopic Changes in Parkinson’s disease
Loss of dopaminergic neurons in substantia nigra –> loss of neuromelanin pigment
Microscopic features of Parkinson’s disease
Lewy bodies Axonal processes (Lewy neurites)
Diagnostic gold standard for Parkinson’s disease
Immunostaining for alpha synuclein
Braak staging of Parkinson’s disease
1 = dorsal motor nucleus of vagus (in dorsal medulla) 2 = pons 3 = substantia nigra 4 = cholinergic neurons 5 = frontal?
What Braak stage are symptomatic Parkinson’s disease patient
Stage 3
Other causes of Parkinsonism (besides Parkinson’s disease)
Multiple system atrophy - alpha synuclein deposited in glial cells (mainly oligodendrocytes)
Progressive supra nuclear palsy
Corticobasal degeneration
EPSE from psychiatric medication
Macroscopic appearance of Pick’s disease
Fronto-temporal atrophy
Microscopic appearance of Pick’s disease
Tau positive pick bodies
Marked gliosis
Neuronal loss
Balloon neurons
