Children and adolescents --> Near 4th ventricle Adults --> Spinal cord

Neuro III (a) Flashcards by Elyaa Saleh

Epi/ Grading of pilocytic astrocytoma

Benign tumours; Grade I (WHO)
* Children and young adults

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Genetics of Pilocytic Astrocytoma

Specific point mutation (V600E) of the BRAF gene

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Location of Pilocytic astrocytoma

* Cerebellum (most common)
* Third ventricle
* Optic pathways
* Spinal cord
* Cerebral hemispheres

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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)

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Epi of Diffuse Astrocytomas

80% of adult gliomas

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loc of Diffuse astrocytomas

Cerebral hemispheres

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CM of Diffuse astrocytomas

1) Seizures
2) Headaches
3) Focal neurologic deficits (related to the site of localisation)

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Classification of Diffuse astrocytomas

1) Well-differentiated astrocytoma (WHO Grade II)
2) Anaplastic astrocytoma (WHO Grade III)
3) Glioblastoma (WHO Grade IV)

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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

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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

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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)

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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)

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Epi of Oligodenroglioma

5-15% of gliomas

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Genetic predisposition of Oligodendroglioma

Deletions of chromosomes 1p and 19q

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Loc of Oligodenroglioma

Frontal and temporal lobes

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which has a better prognosis Oligodenroglioma or astrocytomas?

Oligodendrogliomas

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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

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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

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Epi of Ependymoma

5-10% of the primary brain tumours in individuals < 20 years old

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Loc of Epyndymoma

Children and adolescents –> Near 4th ventricle
Adults –> Spinal cord

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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)

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3 Examples of neuronal Tumours

1) Central Neurocytoma (low-grade)
2) Gangliogliomas (low-grade astrocytoma)
3) Dysembryoplastic Neuroepithelial Tumour (low-grade childhood tumour)

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loc of Central Neurocytoma

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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 ?

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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 e**osinophilic 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

Neuro III (a) Flashcards

(55 cards)