Neuro III (a) Flashcards
Epi/ Grading of pilocytic astrocytoma
Benign tumours; Grade I (WHO)
* Children and young adults
Genetics of Pilocytic Astrocytoma
Specific point mutation (V600E) of the BRAF gene
Location of Pilocytic astrocytoma
* Cerebellum (most common)
* Third ventricle
* Optic pathways
* Spinal cord
* Cerebral hemispheres
Macroscopic Features: ‘
* Cystic lesion with a mural nodule in the wall of the cyst or
* Solid, well circumscribed mass
Microscopic Findings:
* Bipolar cells with long, thin hair-like processes
* Rosenthal fibers
* Eosinophilic granular bodies
* Microcystic changes
features of ?
Pilocytic astrocytoma (WHO GRADE 1)
Epi of Diffuse Astrocytomas
80% of adult gliomas
loc of Diffuse astrocytomas
Cerebral hemispheres
CM of Diffuse astrocytomas
1) Seizures
2) Headaches
3) Focal neurologic deficits (related to the site of localisation)
Classification of Diffuse astrocytomas
1) Well-differentiated astrocytoma (WHO Grade II)
2) Anaplastic astrocytoma (WHO Grade III)
3) Glioblastoma (WHO Grade IV)
Gentic predisposition of Diffuse Astrocytomas
1) Loss of function mutations in p53 and Rb genes (Glioblastomas)
2) Mutations in the IDH1and IDH2 genes (Low grade astrocytomas) –> Important diagnostic utility
Macro features:
* Gray, poorly defined, infiltrative tumours
Microscopic features:
* Mild to moderate hypercellularity
* Variable nuclear pleomorphism
* Fibrillary appearance Fine (GFAP [+]) astrocytic cell processes
* Irregular and Hyper-chromatic “Naked nuclei”
features of?
Well-differentiated astrocytoma -WHO Grade II
Macro features:
* Firm and white
* Soft and yellow
* Cystic degeneration and haemorrhage
Micro features:
* “Glomeruloid” bodies: Larger tufts of microvascular hyperplasia with multiple lumens
* Marked cellularity
* Pseudo-palisading necrosis
features of?
Glioblastoma (WHO Grade IV)
Which type of Diffuse Astrocytoma has the best/worse prognosis
Best –> Well differentiated astrocytomas (survival >5yrs)
Wrose –> Glioblastomas (poor prognosis w/ tx 15 months mean surviaval)
Epi of Oligodenroglioma
5-15% of gliomas
Genetic predisposition of Oligodendroglioma
Deletions of chromosomes 1p and 19q
Loc of Oligodenroglioma
Frontal and temporal lobes
which has a better prognosis Oligodenroglioma or astrocytomas?
Oligodendrogliomas
Macroscopic Features:
* Gelatinous, gray masses, possible with cysts, focal haemorrhage and calcification
Microscopic features:
* Sheets of sphaerical cells with spherical nuclei
* Finely granular chromatin
* Perinuclear halo (“fried egg appearance”)
* Delicate network of anastomosing capillaries (“chicken-wire appearance”)
* Focal or diffuse deposits of calcification
features of?
Well- Differentiated Oligodendroglioma
Diffrence Microscopically btw well- diffrentiated and Anaplastic Oligodendroglioma
Anaplastic (malignant- WHO GARDE III) –> higher cellular densoty, nuclear anaplasia, mitotic activity and necrosis
Well diffrentiated –> WHO GRADE II
Epi of Ependymoma
5-10% of the primary brain tumours in individuals < 20 years old
Loc of Epyndymoma
- Children and adolescents –> Near 4th ventricle
- Adults –> Spinal cord
Macroscopic Features:
* Solid or papillary masses (originating from the ventricular floor)
Microscopic Findings:
* Cells with regular round to oval nuclei
* Abundant granular chromatin
* Dense fibrillary background
* True rosettes (around a lumen)
* Perivascular pseudo-rosettes
featues of?
Conventional Ependymoma (WHO GRADE II)
- Increased cell density, nuclear pleomorphism, high mitotic index, necrosis (Anaplastic Ependymomas)
3 Examples of neuronal Tumours
1) Central Neurocytoma (low-grade)
2) Gangliogliomas (low-grade astrocytoma)
3) Dysembryoplastic Neuroepithelial Tumour (low-grade childhood tumour)
loc of Central Neurocytoma
lateral or 3rd ventricles
Microscopic Findings:
* Evenly spaced, round, uniform nuclei
* Often islands of neuropil
* Densely packed small- to medium- sized, round bland tumour cells
features of ?
Central neurocytoma
CM of Gangliogliomas
Seizures
Cells found microscopically in Gangliogliomas
1) Astrocytic Glial cells
2) mature appearning neurons (Ganglion cells?)
loc of Dysembryoplastic neuroepithelial tumour (DNT)
Superficial temporal lobe
Microscopic Findings:
* Small round neuronal cells arranged in columns and around central cores of processes
* Intra-cortical nodules with myxoid background
* “Floating neurons” within a myxoid fluid (Mucin-filled cyst)
features of?
Dysembryoplastic Neuroepithelial Tumour (DNT)
CM of Dysembryoplastic Nuro-Epithelial tumour (DNT)
Seizures
Embryonal (Primitive) Neoplasms are known to have what distinctive appearance ?
Primitive “small round cell” appearance –> Resemblance to normal progenitor cells of CNS
Macroscopic Features:
* Well circumscribed, gray and friable
* Extension to the leptomeninges
Microscopic Findings:
* Extremely cellular tumours
* Sheets of anaplastic (“small blue”) cells
* Hyperchromatic nuclei
* Mitoses
* Focal neuronal differentiation with Homer-Wright rosettes
featurs of?
Medulloblastoma
Loc of Medulloblastoma
- Midline of the cerebellum (children);
- Lateral cerebellar tumours (adults)
Genetic predisposition
+ prognosis of Medulloblastoma
1) MYC amplifications –> Poor outcome
2) Mutations in genes of the WNT signaling pathway -> More favourable course
3) Mutations activating the Sonic Hedge Hog (SHH) pathway –> Relative good prognosis
epi of primary CNS LYMPHOMAS
Most common Diffuse Large B-Cell Lymphoma (DLBCL); 2% of extra-nodal lymphomas; 1% of intracranial tumours
* Aggressice disease
who is as high risk of developing primary CNS Lymphomas
immune-compromised individuals <> EBV [+]
Macroscopic Features:
* Multiple nodules within the brain parenchyma
* Well defined tumours
* Necroses (EBV[+] tumours)
* Localisation: Deep gray structures, white matter and cortex
Microscopic Findings:
* Diffuse Large B-Cell Lymphomas (DLBCL)
* Perivascular accumulation of neoplastic cells
* Infiltration of the adjacent brain parenchyma
features of?
Primary CNS lymphoma
Loc of primary CNS lymphoma
Deep gray structures, white matter and cortex
Epi Germ cell tumours
90% of cases , Individuals < 20 years old
Most common CNS germ cell neoplasm ?
Germinoma (resemblance to testicular Seminoma)
* seminoma -> lymphocytic infiltrates
Loc of Germ Cell tumours
i. Pineal, ii. Supra-sellar regions
Loc of Meningioma
- Anywhere on the external surfaces of the brain (meninges)
- Within the ventricular system
Micro findings:
* Sheets or clusters of cells without visible cell membranes
* Large nests of epithelioid cells
* Numerous nuclear clear holes
Features of what type of Grade I Meningioma?
Meningotheliomatous (Synctial)
Micro features:
* Elongated cells with abundant collagen deposits between them
* Intersecting fascicles of spindled cells
features of what type of Grade I Meningioma?
Fibroblastic Meningioma
Micro features:
* Combined features of syncytial and fibroblastic tumours
* Psamoma bodies
* characteristic “Whorls”
fetaures of what type of Grade I Meningioma?
Transitional Meningioma
micro features:
* Presence of numerous psammoma bodies
features of what type of Grade I Meningioma?
Psammomatous Meningioma
Micro features:
* Presence of pseudo-psammoma bodies (PAS [+] eosinophilic secretions)
* Tan Appearance on cut surface
features of what type of Grade I Menongioma?
Secretory Meningioma
What stain is used for the identification eosinophilic pseudo-psammoma bodies in Secretory Meningioma ?
PAS ([+])
Micro findings of Atypical (Grade II) Meningioma
- Increased cellularity
- Prominent nucleoli
- Patternless growth
- High mitotic rate
- Foci of spontaneous necrosis
Micro features of Anaplastic (or malignant; Grade III) Meningioma
Resemblance to high grade Sarcoma or Carcinoma
Macroscopic features:
* soft fleshy appearance with papillary (cauliflower-like) configuration
Microscopic features:
* Prominant nucleoli
* Focus of “spontaneous necrosis”
* MIB-1 (Ki-67 > 4%)
features of?
Atypical Meningioma (WHO GRADE II)
Macroscopic features:
* Tumour with irregular contour and inhomogeneous signal characteristics
* Central hypodensity (suggestive of necrosis)
* Tumour with soft, almost gelatinous cut surface (suggestive of high cellularity)
Microscopic featuers:
* Fibrosarcoma-like spindled region
* Carcinoma-like region ; Multiple necrosis
* patchy postitivity to EMA (stain)
* MIB-1 (Ki-67) > 20%
features of?
Anaplastic Meningioma (WHO Grarde III)
Microscopic features:
* Tongue-like protrusions
* Entrapped brain parenchyma [GFAP]
features of?
Brain invasive meningioma (WHO GRADE II)
* GFAB stains the glial cells in the brain parenchyma
the most comon primary sites of Metastic Brain tumours are?
Lung, breast, skin, GI tract
Macroscopic Features:
* Sharply demarcated masses with peri-tumoural oedema
Microscopic features:
* Tall columnar cells
* Cribriform glands
* “Dirty necrosis”
features of?
Metastaic barin tumour from the GI tract (Colon Carcinoma)
CM of Metastaic Brain Tumours
Paraneoplastic syndromes:
1) Subacute cerebellar degeneration
2) Limbic encephalitis
3) Subacute sensory neuropathy
4) Syndrome of rapid-onset psychosis, catatonia, epilepsy and coma
