Neuropathology Central Flashcards
What characterizes a red neurons in acute neuronal injury?
- Shrinkage of the cell body2. Pyknosis of the nucleus3. Disappearance of the nucleolus4. Loss of Nissl (These granules are of rough endoplasmic reticulum (RER) with rosettes of free ribosomes, and are the site of protein synthesis) substance5. Intense eosinophilia of the cytoplasm
What is the histopathologic picture of axonal reaction?
CENTRAL CHROMATOLYSIS: 1. Enlargement and rounding up of the cell body, 2. Peripheral displacement of the nucleus3. Enlargement of the nucleolus4. Dispersion of Nissl substance from the center to the periphery of the cell
Match the ff inclusions with the disease:
- herpetic infection
- cytoplasmic inclusions, as seen in rabies
A. Cowdry body
B. Negri body
#Intracytoplasmic $Intranuclear
1A$ 2B#
When is the Alzheimer Type 2 Astrocyte usually seen?
Individuals with long-standing hyperammonemia due to chronic liver disease, Wilson disease, or hereditary metabolic disorders of the urea cycle.
What heat shock proteins are found in rosenthal fibers?
aB crystallin HSP 27
Rosenthal fibers are thick elongated brightly eosinophilic irregular structures that occur within astrocytic processes
What are seen in the cytoplasm of neurons in myoclonic epilepsy?
Lafora bodies
What are Duret hemorrhages?
hemorrhagic lesions in the midbrain and pons occurring during uncal herniation
What malformation can occur from mutations in the gene encoding the microtubule-associated protein LIS-1, which complexes with dynein and affects the function of the centrosome in nuclear movement?
Lissencephaly
What mutated genes in chromosome X causes neuronal heterotropias, collections of neurons in inappropriate locations along the migrational pathways?
Filamin A and Doublecortin
Where is misshapen lateral ventricles (“bat-wing” deformity) seen?
Agenesis of the corpus callosum
What is status marmoratus?
In perinatal ischemic lesions of the cerebral cortex, the depths of sulci bear the brunt of injury and result in thinned-out, gliotic gyri (ulegyria). The basal ganglia and thalamus may also suffer ischemic injury, with patchy neuronal loss and reactive gliosis. Later, aberrant and irregular myelinization gives rise to a marble-like appearance of the deep nuclei
Which TBI? clinical syndrome of altered consciousness secondary to head injury typically brought about by a change in the momentum of the head (when a moving head is suddenly arrested by impact on a rigid surface).
Concussion
What term is used to describe depressed, retracted, yellowish brown patches involving the crests of gyri most commonly located at the sites of contrecoup lesions (inferior frontal cortex, temporal and occipital poles)
Plaque jaune
When do the following events occur in subdural hematoma?1. Lysis of the clot 2. Growth of fibroblasts from the dural surface into the hematoma 3. Early development of hyalinized connective tissue
Lysis of the clot (about 1 week)
Growth of fibroblasts from the dural surface into the hematoma (2 weeks)
Early development of hyalinized connective tissue (1 to 3 months)
What is the percentage of % resting cardiac output going to the brain % of the total body oxygen consumption going to brain
15% of the resting cardiac output and accounts for 20% of the total body oxygen consumption.
What cells of the brain are the most susceptible to global ischemia of short duration?
- Pyramidal cells in CA1 of the hippocampus (Sommer sector)
- Purkinje cells of the cerebellum
- Cortical pyramidal neurons
What events happen after an infarct at the following timepoints:1. <24h2. 24h to 2 weeks3. More than 2 weeks
- <24h: red neurons
- 24h to 2 weeks: necrosis, macrophages, vascular proliferation
- More than 2 weeks: removal of all necrotic tissue, loss of normally organized CNS structure, and gliosis
When do phagocytic cells start to become the predominant type of cells in an infarcted region?
Phagocytic cells, derived from circulating monocytes and activated microglia, are evident at 48 hours and become the predominant cell type in the ensuing 2 to 3 weeks.
What is the size cutoff for lacunes?
These are lake-like spaces, less than 15 mm wide, which occur in the lenticular nucleus, thalamus, internal capsule, deep white matter, caudate nucleus, and pons, in descending order of frequency
What vascular changes are effected by hypertension?
Hypertension causes a number of abnormalities in vessel walls, including accelerated atherosclerosis in larger arteries; hyaline arteriolosclerosis in smaller vessels; and, in severe cases, proliferative changes and frank necrosis of arterioles chronic hypertension is associated with the development of minute aneurysms, termed Charcot-Bouchard microaneurysms, which may be the site of rupture
What amyloidogenic peptides deposit in vessel walls in CAA?
Abeta40
What protein is affected in CADASIL?
Notch 3 receptor
What is an aneurysmal sac composed of?
At the neck of the aneurysm, the muscular wall and intimal elastic lamina stop short and are absent from the aneurysm sac itself. The sac is made up of thickened hyalinized intima. The adventitia covering the sac is continuous with that of the parent artery.
What is the foix Jouanine disease?
Venous angiomatous malformation of the spinal cord and overlying meninges, most often in the lumbosacral region, associated with ischemic myelomalacia and slowly progressive neurologic symptoms.
What are rod cells?
When microglia responds to injury the nuclei elongate.
Acquired leukodystrophies primarily damage which cell in the brain?
Oligodendrocytes
What is the most benign form of spinal dysraphism?
Spina bifida occulta
When does the neural tube close?
Day 28 of embryonic developement.
Which undergoes radial migration from the germinal matrix to the cortex? Excitatory or inhibitory neurocons?
Excitatory. Respond to cell signal REELIN
Inhibitory neurons undergo tangential migration
Define1. Lissencephaly2. Polymicrogyria3. Neuronal heterotropia4. Holoprosencephaly
- Lissencephaly: reduction in the number of gyria
- Polymicrogyria: Small numerous gyria
- Neuronal heterotropia: Collections of neurons at inappropriate locations along the pathway of migration
- Incomplete separation of the cerebral hemispheres across the midline
What is characterized by an enlarged posterior fossa with a rudimentary vermis and a large midline cyst?
Dandy walker malformation
What area of the brain is most prone to bleeding in premature infants?
Germinal matrix in the junction of the thalamus and the caudate
What plaque is associated with old traumatic lesions? They are depressed retracted, yellowish brown involving the crests of the gyri.
Plaque jaune
What 2 staining methods are used for DAI to demonstrate axonal swelling?
- Silver impregnation
2. Immunoperoxidase stains for axonally transported proteins such as amyloid precursor protein and alpha synuclein
What vessel is involved in:
- Epidural
- Subdural
- Middle meningeal artery
2. Bridging veins
What histopathologic protein accumulation can be seen in chronic traumatic encephalopathy?
Tau containing NF tangles
What percentage of the brain accounts for1. Body weight2. Resting cardiac output3. Body O2 consumption
- 1-2%
- 15%
- 20% (20, O2 get it?)
What are the downstream cellular consequences of ischemia and hypoxia? First is the decrease in oxidative phosphorylation because of lack of o2 and mitochondrial damage followed by…
- Malfunction of the Na K ATPase sodium pump resulting in: efflux of K, influx of Ca resulting in activation of degrading enzymes (phospholipases, proteases, endonucleases), apoptosis induction, opening of the mitochondrial permeability transition pore and influx of Na resulting in water accumulation. Cellular swelling then commences
- Anaerobic glycolysis predominates effectively reducing pH leading to decreased activity of many enzymes and nuclear chromatin clumping
- Detachment of ribosomes resulting in reduced protein synthesis or misfolded proteins that then trigger the pro apoptotic proteins
- ROS species are formed by abnormal oxidative phosphorylation– damage adjacent molecules that are part of the membranes
What are the most sensitive neurons to global ischemic insults?
- Pyramidal cell layer of the hippocampus (CA1 sommer sector)
- Cerebellar purkinje cells
- Pyramidal neurons in the cerebral cortex
What are the layers of the cortex? Out to in
1 Molecular Layer: Axons and dendrites
2 External granular: Densely packed stellate and small pyramidal cells
3 External pyramidal: Loosely packed stellate cells and medium pyramidal cells
4 Internal granular: Densely packed stellate cells only
5 Internal pyramidal: Large pyramidal cells– giant pyramidal cells of Betz
6 Multiform: Multiple sized pyramidal cells with loosely packed stellate cells
In the cerebral cortex the neuronal loss and gliosis are uneven, with preservation ofsome layers and destruction of others, producing a pattern ofinjury termed ______
Pseudolaminar necrosis
In infarcted tissue state the order of appearnce:1. Eosinophilic neurons2. Neutrophils3. Macrophages4. Reactive astrocytes
- Eosinophilic neurons: First 12 hours
- Neutrophils: Up to 48 hours
- Macrophages: 48 hours to 3 weeks
- Reactive astrocytes: Starting 1 week to several months
What is etat crible?
Widening of the perivascular spaces without tissue infarction during arteriolar slcerosis?
What histopathologic vessel feature correlates with lacunar infarcts?
Arteriolar sclerosis
Size of lacunar infarct until?
15mm
AKA subcortical vascular dementia
Binswanger disease
What are the 2 processes that lead to HTN hemorrhages in HTN patients?
- Hyaline change in the vessels making them vulnerable to rupture
- Charcot Bouchard microaneurysms LESS THAN 300 MICROMETERS
What are the two ways to differentiate between arteriolar sclerosis with HTN VS vessel affected by amyloid angiopath?
- Deposition of amyloid in CAA2. NO FIBROSIS in CAA
Misfolding of the extracellular domain of the NOTCH3 receptor leads to what small vessel disease?
CADASIL: Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy
What are the normal layers of vessels?
Tunica Intima: Endothelial layer, Basement membrane, Subendothelial layer, Internal elastic membrane
Tunica Media: Smooth muscle cells, external elastic lamina
Tunica Externa: Collagen fibers and vasa venorum
What vessel layers are missing in the sac of aneurysms?
Smooth muscle and internal elastic lamia
What mendelian disorders increase the risk for the development of aneurysms?
- AD Polycystic kidney disease
- Ehlers-Danlos syndrome type 4
- NF1
- Marfan syndrome
What is the most common location for:
- Saccular aneurysms
- Cavernomas
- Capillary telangiectasia
- Acomm
- Cerebellum then pons
- Pons
Which has intervening normal brain parenchyma?
Cavernomas
Capillary telangiectasia
Capillary telangiectasia
What are the most common bacterial organisms associated in:
- Infants
- Young adults
- Older adults
- Infants: E coli, Group B Streptococci
- Young adults: N meningitidis
- Older adults: S pneumoniae, L monocytogenes
The Waterhouse-Friderichsen syndrome results from meningitis-associated septicemia with hemorrhagic infarction
of the adrenal glands and cutaneous petechiae occurs most often with what organisms?
It occurs most often with meningococcal
and pneumococcal meningitis.
Chronic adhesive arachnoiditis most usually occurs after infection with what bacterial organism?
Pneumococcal meningitis
What bacterial organism has a basal distribution of exudates?
H. influenzae
Pneumococcal densest over the cerebral convexities
Which CSF parameter is usually normal in aseptic meningitis?
Sugar
What are the 2 characteristic findings in viral encephalitis?
- Perivascular cuffs of lymphocytes
2. Micrglial nodules– these nodules have multinucleated giant cells in HIV
What intranuclear inclusion body is found in HSV 1 encephalitis?
Cowdry A
Varicella zoster or Herpes zoster hides where after the initial cutaneous vesicular eruption?
Sensory neurons of the dorsal root or the trigeminal ganglia– from here they reactivate and present as shingles!
Where is infection with CMV localized in the brain?
Severe hemorrhagic necrotizing ventriculoencephalitis in the paraventricular subependymal regions of the brain
What is the pathognomonic mircroscopic finding in rabies?
Negri bodies, the
pathognomonic microscopic finding, are cytoplasmic, round to
oval, eosinophilic inclusions that can be found in pyramidal
neurons of the hippocampus and Purkinje cells of the cerebellum,
sites usually devoid of inflammation
The reactivation of what virus causes PML?
JC virus, a polyomavirus
Small cysts (soap bubbles) seen within the parenchyma of patients with cryptococcal meningitis is usually located where?
BG in the distribution of the lenticulostriate arteries
MINIMAL OR ABSENT INFLAMMATION or GLIOSIS in these lesions
What are abnormal forms of a cellular protein that
cause rapidly progressive neurodegenerative disorders
that may be sporadic, familial or transmitted.
Prions
Which form of PrP is present in those with prion disease?
PrPsc– the abnormal beta pleated sheet isoform
Normal is an alpha helix containing isoform PrPc
Homozygosity at codon 129 is protective against development of prion disease. T/F
F
Heterozygosity is.
What are the pathognomonic findings in CJD?
spongiform transformation of the cerebral
cortex and, often, deep gray matter structures (caudate,
putamen); this multifocal process results in the uneven formation
of small, apparently empty, microscopic vacuoles of varying
sizes within the neuropil and sometimes in the perikaryon of
neurons– THERE IS NO INFLAMMATION
How is vCJD different from CJD
- Younger onset
- Behavioral disorders figured prominently in the early stages
- Syndrome progressed more slowly
What gene is mutated in the familial forms of prion disease?
PRPN
Which cells of the immune system are the MAIN EFFECTORS of the pathology of MS?
TH1: Secrete interferon gamma which activates macrophages
TH17: Recruits leukocytes that injure the myelin
What are the key histologic features of an active VS inactive plaque?
Active: Macrophage with PAS positive debris, Perivascular cuffs of lymphocytes and monocytes
Inactive: Little to NO myelin, astrocytic proliferation with lgiosis
What are the features of CSF in MS
Mild elevation of protein
Oligoclonal IgG bands
Compared to MS what is the main effectors of damage in NMO?
B cells that make antibodies against aquaporin-4 the main water channel of astrocytes
What is the main differentiating clinical and histologic feature of ADEM compared to MS?
ADEM is monophasic. All lesions are of the same age
How to differentiate ODS lesion from MS?
No inflammation– all lesions at the same stage
Indicate whether the ff disease is primarily a taupathy or synucelinopathy
- PSP
- CBD
- MSA
- Lewy body dementia
- Parkinson disease dementia
- AD
- FTLD
- PSP tau
- CBD tau
- MSA synuclein
- Lewy body dementia synuclein
- Parkinson disease dementia synuclein
- AD tau but note that beta-amyloid plaques also present
- FTLD Tau
What disease entities have TDP-43 and FUS proteins?
Frontotemporal lobar degeneration
Amyotrophic lateral sclerosis
What are the two proteins that accumulate in AD?
Tau microtubule binding protein forming tangles and beta amyloid peptides forming plaques
What is he critical initiating event of developement of AD?
beta amyloid peptide generation
Mutations in the gene for tau gives rise to what kind of dementia? How about mutations in the amyloid precursor protein?
FTD
AD
What is APP?
Amyloid precursor protein (APP) is a cell
surface protein with a single transmembrane domain
that may function as a receptor, possibly for prion
protein (PrPc) among other ligands.
What consecutive cleavage of APP results in the formation of the beta amyloid peptide?
Beta amyloid converting enzyme followed by gamma secretase produces beta amyloid monomer –> oligomers –> aggregates –> amyloid fibrils –> plaques
How dose beta amyloid effect neuronal damage?
- Kinase activation that results in tau phosphorylation leading to microtubule disassembly
- Synaptic dysfunction
- Cell death
T/F AD pathology is an eventual feature of the cognitive impairment of Down’s syndrome patients.
T
What chromosome is the gene for amyloid precursor protein located in?
- Like down syndrome
What is tau?
Tau is a microtubule-associated
protein present in axons in association with the microtubular
network. With the development of tangles in
AD, it shifts to a somatic-dendritic distribution, becomes hyperphosphorylated, and loses the ability to bind to microtubules.
The dosage of which allele coding for apolipoprotein E on chromosome 19 correlates with the risk of AD and its age of onset?
Epsilon 4
E3 E2 E4
What correlates better with the degree of dementia? Plaques or tangles?
Tangles
What CSF levels of beta amyloid protein and phosphorylated tau would one expect in the CSF?
High tau
Low beta amyloid
What are diffuse plaques made of? VS neuritic plaques.
Diffuse plaques are believed to be an early
stage of plaque development, based on studies of individuals with trisomy 21.
While neuritic plaques contain both Aβ40 and
Aβ42, diffuse plaques are predominantly made up of Aβ42.
What form of beta amyloid is found predominantly in cerebral amyloid angiopathy?
beta amyloid 40
What is contained in the Pick bodies in FTLD?
Tau aggregation
Pick’s disease
How does phosphorylation affect tau protein?
- Propensity to aggregate
2. Unable to bind to microtubules
What is TDP-43?
TDP-43 is an RNA-binding protein
with roles in RNA processing as well as in the formation of stress granules.
Which among the ff FTLD TDP genetic mutations is NOT linked to ALS?
- C9orf72
- TDP 43
- Progranulin
Progranulin
Mutations in FUS, an RNA binding protein can result in which neurodegenerative diseases?
FTLD and ALS
What is the major component of a Lewy body, the diagnostic hallmark of PD?
Single or multiple cytoplasmic eosinophilic round inclusions with a dense core and pale halo. Made up of filamtes composed of alpha synuclein
Oligemers are toxic to neurons and can be spread in a prion like manner
What are the normal functions of the following PD associated proteins (Autosomal recessive)
- DJ-1
- PINK1
- Parkin
DJ1: acts as a transcriptional regulator– also with a cytoprotective effect during times of oxidative stress
PINK1 (kinase) and Parkin (E3 ubiquitin ligase) joint together if there is mitochnodrial dysfunction: Facilitates clearance of dysfunctional mitochondria through mitophagy
LRRK2 mutation results to what type of PD? AD or AR
AD
What is the general pathologic difference between PSP and CBD?
In general, with PSP there is a greater burden of tau-containing lesions in brainstem and deep gray matter, while in CBD the balance is shifted more toward cerebral cortical involvement.
What are the 3 systems affected in MSA?
- the striatonigral circuit (leading to parkinsonism),
- olivopontocerebellar circuit (leading to ataxia), and
- the autonomic nervous system including the central elements
(leading to autonomic dysfunction, with orthostatic
hypotension as a prominent component)
Where can one find the alpha synuclein in MSA patients?
Oligodendrocyte cytoplasm making the cells more sensitive to oxidative stress and show impaired interaction with the cell matrix
What areas are atrophic in the ff forms of MSA?
- Cerebellar
- Parknsonian
Cerebellar: Cerebellum, pons
Parkinsonian: Substantia nigra and striatum (putamen and caudate)
What is phenomenon of anticipation found in diseases like Huntington’s disease?
Repeat expansions occur during spermatogenesis, so that
paternal transmission is associated with early onset in the next generation, a phenomenon termed anticipation.
What is the normal number of copies of CAG repeats in the first exone of the HTT gene?
6-35
Where is the HTT gene located?
Chromosome 4p16.3
What transcriptional regulators are bound by the Huntingtin protein?
How does altered expression of BDNF in HD harm the patients?
Those involved in mitochondrial
biogenesis and protection against oxidative injury,
Altered expression of the growth factor brainderived
neurotrophic factor (BDNF), and deleterious effects
of protein aggregates, which may disrupt both proteasomal
and autophagic degradation pathways.
What is the most affected part of brain atrophy seen in Huntington’s disease?
ATROPHY OF THE CAUDATE NUCLEUS
Which of the following SCAs have the following features? What are their inheritance patterns?
- Ataxia with retinal degeneration
- Pure cerebellar ataxia
- Cerebellar ataxia and seizures
- Associated with slowed eye movements and sometimes dementia
- With muscle weakness and atrophy MOST COMMON AKA Machado Joseph disease
- With sensory loss
- Ataxia with retinal degeneration SCA 7
- Pure cerebellar ataxia SCA 6
- Cerebellar ataxia and seizures SCA 10
- Associated with slowed eye movements and sometimes dementiaSCA 2
- AKA Machado Joseph disease SCA 3
- With sensory loss SCA 4
All are Autosomal Domninant ataxias
What protein is diminished in Friederich ataxia? What trinucleotide repeat is involved? How is it inherited?
Frataxin
GAAA from chromomosome 9q13
AR
Besides ataxia, spasticity and weakness what are the other two main features of friedrich ataxia?
Sensory neuropathy and cardiomyopathy
25% will also have DM
What gene is involved in ataxia telangiectasia and what chromosome is it located in?
ATM gene (AT mutated) Chromosome 11q22-q23
What cancer is associated with AT?
T cell leukemias
Mutation of what gene accounts for the most frequent cause of familial ALS (20%) of all ALS?
FUS
TDP 43
c9orf72
SOD1
c9orf72 40% (ALSO INVOLVED IN FTLD)
SOD1 20%
What ALS variant:
- Lower motor neuron involvement predominates
- Upper motor neuron involvement predominates
- Progressive muscular atrophy
2. Primary lateral sclerosis
What is Kennedy disease?
X linked polyglutamine repeat expansion causing Spinal and bulbar muscular atrophy
What gene and protein is involved in SMA?
SMN protein– involved in the assembly of the spliceosome
SMN1 and SNM2 genes on chromosome 5q
How to dfx leukodystrophies from demyelinating disease?
The leukodystrophies
typically present with an insidious and progressive loss of cerebral function, often at younger ages, and are associated with diffuse and symmetric changes on imaging studies.
What histologic findings is diagnostic of Krabbe disease?
A unique and diagnostic
feature of Krabbe disease is the aggregation of engorged
macrophages (globoid cells) in the brain parenchyma and
around blood vessel
What enzyme is missing and what compound accumulates in patients with:
- Krabbe disease
- Metachromatic leukodystrophy
- Beta galactosidase: Galactosylsphingosine
2. Lysosomal enzyme arylsulfatase A: Sulfatides–cerebroside sulfate
In adrenoleukodystrophy, what lipid is increased? Why?
Very long chain fatty acids (VLCFAs)
Mutation in a member of the ABCD1 which is involved in the transport of molecules into the peroxisome.
Besides demyelination how else does adrenoleukodystrophy present?
Adrenal insufficiency
T/F Leukodystrophies target white matter while mitochondrial disease targets gray matter
T
What does MELAS stand for and what gene is involved in the disease?
Mitochondrial encephalomyopathy, lactic acidosis and stroke like episodes.
MTTL1
What are the 2 key components of MERRF?
Myoclonic epilepsy
Myopathy
Some also have neuronal loss from the cerebellar system causing ataxia
Deficiency of what vitamin causes psychotic symptoms with ophthalmoplegia that if uncorrected leads to a prolonged and largely irreversible state of short term memory disturbance and confabulation.
B1 Thiamine
Wernicke encephalopathy –> progressing to Korsakoff syndrome
Bilateral necrosis of the globus pallidus may be seen in which toxic disorder?
How about degeneration of retinal ganglion cells?
Carbon monoxide
Methanol
What are the 3 layers of the cerebellar cortex?
Molecular
Purkinje
Granular
The histologic changes are atrophy and loss of granule cells predominantly in the anterior
vermis In advanced cases there is loss of
Purkinje cells and proliferation of the adjacent astrocytes
(Bergmann gliosis) between the depleted granular cell layer
and the molecular layer of the cerebellum. Pertains to what toxic disorder?
Chronic alcohol use
What are the 4 molecular classifications of GBM?
Which is MOST associated with secondary GBM?
- Classic
- Proneural – most common type associated with secondary GBM
- Neural
- Mesenchymal
The mutant form of IDH1 if seen in high grade astrocytoma is associated with a better or a worse outcome?
better
Classic type or proneural type GBM?
PDGFRA overexpression
EGFR amplification
PDGFRA overexpression– proneural
EGFR amplification– classic
What is found is usually found pilocytic astrocytomas?
TP53 mutations OR BRAF alterations
BRAF alterations
What is the most benign type of brainstem glioma?
Dorsally exophytic glioma
What is the most common genetic alteration found in oligodendroglioma?
IDH1 and IDH2 mutation
What are the 2 most striking features of ependymoma histology?
- Gland like round structures, rosettes/ canals, that resemble the embryologic canal with long processes extending into the lumen
- Perivascular pseudorosettes
What is the most common neuronal tumor?
Gangliogliomas are tumors comprised of a mixture of mature neuronal and glial cells.
Where are central neurocytoma tumors found?
Lateral or third ventricles
Identify which type of medulloblastoma
- Classic or large cell histology, WITHOUT MYC amplification, intermediate prognosis
- MYC amplification, Classic or large cell histology, isochromosome 17, WORST prognosis
- Classic histology, monosomy at chromosome 6, BEST prognosis, nuclear expression of beta catenin
- Mutations involving the sonic hedgehog signaling pathway, nodular desmoplastic histology
- Group 4
- Group 3
- Group 1
- Group 2
What kind of rosettes are seen in medulloblastoma and neuroblastoma?
Homer wright rosettes
What is the most common cytogenetic abnormality in meningiomas?
loss of chromosome 22, especially the long arm
(22q). The deletions include the region of 22q12 that harbors
the NF2 gene, which encodes the protein merlin; as expected, meningiomas are a common lesion in the setting of NF2
What is the histologic picture of the most common type of meningioma in the brain?
How about in the spine?
Syncytial/Meningothelial: with whorled clusters of cells that sit in tight groups without visible cell membranes
Psammomatous: Psammoma bodies– calcified syncitial nests of the meningothelial cells
What WHO grade are the following meningiomas?
- Those showing brain invasion
- Papillary and rhabdoid
- Clear cell and choroid
- Those with 20 or more mitoses per 10 high power fields
- Those with 4-19 mitoses per 10 high power fields
- II
- III
- III
- II
What are the atypical features that can promote a grade 1 meningioma to grade 2 if at least 3 of them are present?
- Increased cellularity
- Small cells with high nuclear to cytoplasmic ratio
- Prominent nucleoli
- Patternless growth
- Necrosis
Identify the tumor associated with the ff tumor syndromes:
- Cowden
- Li-Fraumeni
- Turcot
- Gorlin
- Cowden: Dysplastic gangliogliocytoma Lhhermitte-duclos disease (PTEN gene)
- Li-Fraumeni: Medulloblastomas (TP53 gene)
- Turcot: Medulloblastoma, glioblastoma (APC gene)
- Gorlin: Medulloblastoma (PTCH gene)
What proteins are encoded by the following genes associated with tuberous sclerosis?
TSC1
TSC2
TSC1: Hamartin – Chromosome 9
TSC2: Tuberin – Chromosome 16
Together they form a complex that inhibits the kinase mTOR– a key regulator of protein synthesis
How does alteration in VHL protein cause polycythemia in patients with Von Hippel Lindau disease?
VHL gene is a tumor suppresor gene that encoudes VHL that is a component of a ubiquitin ligase complex that down regulates hypoxia induced factor 1 a transcription factor involved in regulating the expression of EPO and VEGF
