CNS Flashcards
benign mimics of malignancy
radiotherapy
infarcts
demyelination
infection
gliosis
pineal cyst (adjacent gland is cellular)
infarcts - check for…
thrombi/emboli
amyloid
vasculitis
hypertension
demyelination
MS
PML
central pontine myelinolysis
infections
JC virus
HSV (esp temporal lobe)
CMV
cryptococcus
toxoplasmosis
cysticercosis
hydatid cyst
malignant mimics of benign
LG diffuse astrocytoma
germinoma with inflammation
haemorrhage/necrosis in a tumour
nearly normal brain
vessels: amyloid angiopathy, vasculitis, hypertension, emboli
degenerative: Alzheimers, Lewy body
infection: spongiform encephalopathy
tumour: intravascular DLBCL
other: hippocampal sclerosis, pituitary apoplexy
HIV encephalopathy
encephalitis (microglial nodules with giant cells)
leukoencephalopathy (diffuse demyelination)
infection
malignancy
foamy macrophages
demyelination
infarct
infection
lymphoma (treated with steroids)
granulomas
infection
sarcoid
vasculitis (CNS or systemic)
germinoma
cysts (categories)
glial
ependymal
arachnoid
epithelial
epithelial cysts
Rathke cleft: sellar, resp or non-keratinising sq epithelium
colloid: 3rd ventricle/FOM, cuboidal +/- cilia
dermoid: midline, keratinising sq, sample to exclude teratoma
epidermoid: more lateral, keratinising sq
foregut cyst: anterior spinal cord, mucinous or resp epithelium
cystic neoplasm
glial cysts
pineal
simple (cerebellum)
syrinx (spinal cord)
cystic neoplasm
craniopharyngioma
pilocytic astrocytoma
PXA
ganglioglioma
haemangioblastoma
papillary craniopharyngioma vs epidermoid cyst
CP: sellar/suprasellar, no keratin/granular layer
grading (atypical/anaplastic forms)
anaplastic astrocytoma: 2/3 mitoses/10HPF (no MVP or necrosis)
atypical meningioma: 4 (or other criteria)
anaplastic ependymoma: 5 (+/- MVP and necrosis)
anaplastic oligodendroglioma: 6 (+/- MVP and necrosis)
anaplastic meningioma: 20
atypical meningioma
4 or more mitoses per 10 HPF
or
brain invasion
or
3 of: cellularity, small cells, prominent nucleoli, sheeting, necrosis
papillary neoplasms
papillary ependymoma (GFAP+)
choroid plexus papilloma (transthyretin+, CK+, EMA-)
papillary meningioma (EMA+)
metastatic ca (EMA, CEA+)
genetics for classification
astrocytoma/glioblastoma: IDH
oligodenroglioma: IDH, 1p19q
ependymoma: RELA fusion (supratentorial only)
medulloblastoma: WNT-activated, SHH-activated +/- TP53, nonWNT/nonSHH (GAB1, YAP1 and b-catenin as surrogates)
diffuse midline glioma: H3 K27M mutation
metastases
melanoma
carcinoma: lung, breast, kidney, thyroid, colon
AVM vs cavernous angioma (both cause seizures and haemorrhage)
AVM: artery-vein connections, varied wall thickness, abnormal elastic lamina, intervening gliotic brain
CA: compact thin- or thick-walled vessels
gliosis vs diffuse astrocytoma
astrocytoma: radiology, nuclear atypia, clustering, p53/ki67
infarct vs demyelination
demyelination:
loss of myelin (LFB) (also lost in infarct)
preserved axons (Bielschowsky silver or NF)
foamy macrophages (CD68)
chondromyxoid lesions of CNS
chordoma (sacrum and clivus): cords+physaliferous cells, CK/EMA/s100/brachyury+
myxopapillary ependymoma (cauda equina): papillary with hyalinised vessels, GFAP+ EMA-
chordoid meningioma (dura): whorls/inclusions/psammoma bodies, CK- EMA+
chondrosarcoma: malignant cartilage, s100+/- EMA/GFAP-
schwannoma vs fibrous meningioma
both s100+
meningioma: EMA+
meningioma vs SFT vs HPC
SFT/HPC: both STAT6+ CD34+
HPC: high cellularity, diffuse reticulin network
SFT: patternless, hypo and hypercellular, collagen fibres, focal reticulin
haemangioblastoma vs RCC
haemangioblastoma: inhibin, CD56+
RCC: CD10, CK, PAX8+
glioma biomarkers
IHC:
IDH R132H: + in secondary GBM, and diffuse oligo/astro (required for new WHO categories; do IDH sequencing if - ) - better response to therapy
ATRX: usu lost in diffuse astro (cf oligo)
P53: diffuse astro (cf oligo)
Ki67
BRAF V600E: suggests PXA or GG (cf diffuse gliomas)
(also Olig2: marker for diffuse gliomas (not just oligodendroglioma))
FISH:
1p19q: oligodendroglioma
EGFR ampl: wild type glioblastoma
10q23 (PTEN) del: wild type glioblastoma
Diagnostic genetics:
MGMT promoter methylation (by PCR): better response of GBM to temozolomide (cos no DNA repair)
BRAF mutation
DDX non-traumatic bleed
hypertension
CAA (do beta-amyloid stain in all bleeds over 50!)
anticoagulation/coagulopathy
AVM/aneurysm
tumour
DDX hyalinised vessels
amyloid
hypertension
vasculitis
radiotherapy