3. Neuropathology Flashcards
Primary brain vesicles
Forebrain (prosencephalon) - tele and dien
Midbrain (mesencephalon) - mesen
Hindbrain (rhombencephalon) - meten and myelen
Secondary brain vesicles
Telecephalon Diencephalon Mesencephalon Metencephalon Myelencephalon
Primary neurulation
Formation of neural plate (day 18-19)
Neural folds (20-21)
Closure of neural tube (22)
Rostral then caudal
Secondary neurulation
Development of neural tube (day 28)
species specific
What spinal level does spinal cord end during prenatal life at 12 week, 15 week and 24 week?
C5, S3, S1
What spinal level does spinal cord end at newborn and adult life?
L3, L1-2 (end of dura/arachnoid sac at S2)
Tissue repair in fetus vs adult brain
Macrophages cause phagocytosis (without gliosis) -> pseudoprimary malformation
(hydranencephaly or porencephalic cyst before or at early 2nd trimester)
Subependymal germinal matrix hemorrhage occur in which population?
Prematurely born (<1500 kg) within 3 days after delivery
Pathogenesis of germinal matrix hemorrhage?
Periventricular area with fragile microcirculation stroma
Hypoxic stress -> autoregulation fails and excessive perfusion ruptures GM microcirculation
Grades of GM hemorrhage
I confined in GM
II filling lateral ventricles
III with distention
IV parenchyma
Usual location of GM hemorrhage
Head of caudate > thalamus > behind foramen of monro
Where do contusions occur most frequently?
Frontal and temporal lobes
Traumatic epidural hematoma source of bleeding?
Middle meningeal artery
Less common: laceration of venous sinus (transverse sinus from occipital fracture)
Duret hemorrhage?
Delayed upper brainstem hemorrhage from rapidly evolving descending transtentorial herniation
Pathophysiology of Duret hemorrhage
Stretching/laceration of pontine perforating branches of basilar artery
Diffuse axonal injury?
Axonal damage
parasagittal white matter, corpus callosum, internal capsule, cerebellar peduncles
Duret hemorrhage vs brainstem small tissue-tear hemorrhages in DAI?
Both in upper brainstem, but Duret is delayed and in paramedian areas, whereas DAI located in dorsolateral brainstem
Microscopic timeline picture of DAI?
2-12h Axonal swellings (beta-amyloid precursor protein), then axonal disconnection, then microglial clusters around degenerating axons (5-10 days)
Classify DAI
I: frontal/temporal, cerebellar and internal capsule
II: corpus callosum (splenium)
III: brainstem/cerebellar peduncles and corticospinal tracts
Biochemical changes in DAI
1h: neurofilament immunoreactivity 4-5: accum of bAPP 6h: ubiquitin 1d-2m: axonal swelling 2m-y: wallerian degeneration/demyelination
Which type of temporal bone fracture results in conductive hearing deficit?
Longitudinal temporal bone fracture
Transverse causes more direct nerve damage ith sensorineural hearing deficit (more forceful)
Most striking microscopic finding in lisencephaly type I?
Cortex made from 4 layers (molecular - external neuronal - cellular - internal nuronal)
Macroscopic and microscopic picture of mesial temporal lobe (hippocampal sclerosis)
Ammon’s horn sclerosis
Macroscopic: hippocampus smaller than other side, enlarged temporal horns
Microscopic: neuronal loss in CA1, gliosis
Rasmussen syndrome
Rare disorder in children
Progressive unilateral neurologic deficit + sudden onset epilepsy refractory to medical treatment.
Hemiplegia, hemianopsia, intellectual deterioration
Microscopic picture of Rasmussen syndrome
Like chronic viral encephalitis - lymphocyte cuffs around blood vessels, microglial nodules
What are rosenthal fibers
Eosinophilic bodies
See in neoplasms (juvenile pilocytic astrocytomas), around craniopharyngiomas, multiple sclerosis plaques, Alexander disease
Classifications of astrocytomas
Grade 1 (juvenile pilocytic): GFAP staining, rosenthal fibers Grade 1 (subependymal giant cell): assoc. with tuberous sclerosis Grade 2 (diffuse): nuclear atypia but no mitosis, moderately increased cellularity Grade 2 (pleomorphic xanthoastrocytoma): pleomorphic lipidized cells in bg of reticulin network) Grade 3 (Anaplastic): nuclear atypia and mitosis Grade 4 (GM): nuclear atypia, mitosis, microvascular proliferation and necrosis Grade 4 (Gliomatosis cerebri): extensively diffuse at least 3 lobes, superficial and/or deep gray matter
Primary vs secondary glioblastoma
Primary (age>55, males) - EGFR overexpression, PTEN
Secondary (younger, women) - 2/3 TP53 mutations and no EGFR amplifications
Colloid cysts
Usually anterior 3rd ventricles
Glistening cysts with mucin - outer fibrous connective tissue capsule lined by ciliated pseudostratified epithelium, PAS+ mucin
Craniopharyngioma histology
Squamous epithelium, keratin
Schwannoma histology
Verocay body (Antoni A -dense and B - loose patterns) - palisading nuclei
What are verocay bodies?
Densely packed whorled arrangements in palisaded cells of Antoni A areas of schwannomas
Which tumors show dual histologic patterns?
Schwannomas
Pilocytic astrocytoma
Stains for schwannoma
S100, Leu7, laminin, vimentin, collagen IV
Central neurocytoma histology
Neuroepithelial tumor with uniform round cells with nucleus-free areas of neuropil.
Synaptophysin positive
Which bone tumors have giant cells?
Giant cell tumor
Aneurysmal bone cyst
S100 + stains which tumors (7)?
Schwannoma Eosinophilic granuloma Paraganglioma Hemangioblastoma Chordoma Esthesioneuroblastoma Meningioma (20%)
Specific stains for melanoma
MART-1 and HMB-45
Subtypes of meningiomas that are PAS+?
Secretory meningioma
Secretory meningiomas stain what +?
PAS
Cytokeratin
CEA
2 common + stains for meningiomas
EMA and vimentin
Hemangiopericytoma stains
Reticulin, vimentin, vWF
EMA stains distinguish which tumors?
Hemangiopericytoma (-) vs meningioma (+)
Stains for germinoma
PLAP (placental alk phos), c-kit
Blepharoplasts
Intracytoplasmic basal bodies
Ependymoma
Which chromosomes are assoc. with meningioma progression?
Chromosome 1 alteration and chr22 deletion
Derivative of schwann cells
neural crest cells
Mode of inheritance of neurofibromatosis type 1
Chr 17, autosomal dominant
Fried egg appearance on H&E tumor?
Oligodendroglioma
Reed-sternberg binucleated cells tumor?
Hodgkin
Flexner-Wintersteiner rosettes tumor?
Retinoblastomas
Small, round blue cell tumors of childhood?
Neuroblastoma Chondrosarcoma Rhabdomyosarcoma Lymphoma Ewing sarcoma
Classification of human prion dx?
- Idiopathic (CJD, sporadic fatal insomnia)
- Familial
- Acquired (kuru, CJD)
CJD on histology
Spongiform appearance (vacuoles)
Alzheimers on histology
Senile plaques and neurofibrillary tangles, neuronal loss
What are senile plaques?
Deposits of Abeta peptides
What are neurofibrillary tangles?
Intracellular inclusion bodies (tau proteins)
Alzheimer macroscopically?
Cerebral atrophy in mesial temporal structures
