CNS Tumors Flashcards
The most common intracranial tumor worldwide is the?
Glioma
- Astrocytoma
- oligodendrogliomas
- ependymoma
Followed by
- meningioma
- pituitary adenoma
Classification of CNS tumors
- Gliomas
- Embryonal neoplasms; medulloblastoma
- Neuronal tumors; central neurocytoma, ganglioglioma
- Meningioma
- Metastatic tumors
Types of Astrocytoma
Derived form astrocytes
- Diffuse Astrocytoma (80% of primary brain tumor)
- Pilocytic Astrocytoma
Most common site and age for diffuse Astrocytoma?
Site
- cerebral hemispheres
- cerebellum
- brainstem
- Spinal cord
Age
- 4th -6th decade of life
Classification of diffuse astrocytoma ?
- Well differentiated astrocytoma (grade 2)
- Anaplastic astrocytoma (grade 3)
- Glioblastoma (grade 4)
Gross and microscopy features of well differentiated diffuse astrocytoma?
Gross
- Poorly demarcated infiltrating tumor
- grey, firm/soft, gelatinous
- may show cystic degeneration
Microscopy
- increase in astrocytic glial tumor cells (mild to moderate cellularity)
- Fibrillary background (due to cytoplasmic processes of astrocytes)
- variable degrees of nuclear pleomorphism
Immunohistochemistry
- Glial finrillary acid protein (GFAP) positive
Anaplastic astrocytoma features
- Increased cellularity
- Cellular and nuclear pleomorphism
- Anaplasia
- Presence of mitotic figures
- Rapid growth of the tumor
Glioblastoma gross features (grade 4)
- Variegated appearance (white and firm areas with soft and yellow necrosed areas)
- cystic degeneration
- colors represent multiple areas of recent (red) and old (yellow) hemorrhage
Microscopic features of Glioblastoma
- Increased cellularity
- Marked cellular and nuclear pleomorphism
- Frequent mitosis
- Anaplasia
- Necrosis
- Endothelial cell proliferation (forming tufts of piled up cells)
- May be glomeruloid body (marked endothelial cell proliferation
Types of necrotic patterns in Glioblastoma?
- Serpentine pattern of necrosis
- Pseudo-palisading (garlanding)
• edges of the necrotic area is surrounded by the palisading tumor cells
What are the two forms of Glioblastoma ?
Primary;
- Arises de novo (no preexisting low grade astrocytoma)
- occur in older patients
Secondary;
previously had low grade astrocytoma
Occur in younger patients
Acquired mutations in Glioblastoma ?
- P53, RB
- Clinical features: seizures and headaches
Radiological features of Glioblastoma?
- Shows mass effect and Edema of brain adjacent to the tumor
- Abnormal vessels that are leaky demonstrate contrast enhancement on imaging
- Grave 4 ; poor prognosis
- grade 2; remain static or progress slowly over a number of years
Pilocytic astrocytoma features ?
In children and young adults
Good prognosis
Site
- site located in the cerebellum, floor and walls of the third ventricles
- well circumscribed
Microscopic features of Pilocytic astrocytoma ?
- Biphasic pattern
- loose microcystic areas
- rosenthal fibers and eosinophilic granular bodies
Oligodendroglioma (grade 2)
- Site; common in white mater of cerebral hemisphere
- Well circumscribed
- better prognosis than astrocytoma
- Deletion of chromosomes 1p 19Q
Microscopic features of oligodendrocytoma ?
Sheets of round, small l, regular cells
- Nuclei: spherical, with fine granular chromatin
- Cytoplasm: clear halo of cytoplasm surrounding the nuclei (fried egg appearance )
- Stroma: anastomosing capillaries (chicken wire appearance)
- Calcification (calcospherites) common
- mitotic figures is usually not seen
What are the three cs of oligodendrocytoma?
- Clear holo of cytoplasm surrounding the nuclei (fried egg appearance)
- Chicken wire appearance (anastomosing capillaries)
- Calcification
Ependymoma features
Site
- first 2 decades; 4th ventricle
- adults: Spinal cord associated with NF2
Gross and microscopic features of ependymoma
- well demarcated from adjacent brain parenchyma
- resemble normal ependymal cells
- cells have well defined cell membrane
- EPENDYMAL ROSETTES
- PERIVASCULAR PSEUDO-ROSETTES; tumor cells are arranged around vessels.
Special stain and immunochemistry for ependymoma
Stain
- PTAH stain
- PTAH positive blepharoplasts (basal bodies of cilia of Ependymal cells)
Immunohistochemistry
- GFAP positive
Embryonal tumors are of what origin?
Neuroectodermal origin (consisting of primitive, undifferentiated cells)
Most common - medulloblastoma
Medulloblastoma
- Neuronal and glial markers may be expressed
- children mostly (20% brain tumors in children)
- exclusively in cerebellum
Children: midline cerebellum
adults: lateral cerebellar hemispheres
Gross - well circumscribed, gray and friable
Microscopic features of medulloblastoma?
- Ana-plastic small blue cells
- numerous mitotic figures
-
HOMER-WRIGHT rosette: central neutrophil (pink material) surrounded by primitive tumor cells
gFAB positive
Drop metastases of medulloblastoma is seen in?
- Metastasis from the cerebellum to the cauda equina
- Spread through CsF
- spread may present as modular masses anywhere in the CnS
Clinical features and prognosis of medulloblastoma
Poor prognosis in untreated patients
MYC application - Poor prognosis
Clinical features;
- cerebellar dysfunction
- hydrocephalus (occlusion of csf flow )
Meningiomas features?
- Benign tumor arising from meningothelial cell of the arachnoid matter
- 20% of all primary intracranial neoplasms
- 5th and 6th decade
- 3:2 (female:male)
Molecular genetics of meningioma?
- Sporadic: NF2 mutation
- Iatrogenic; prior radiation to the cranium
- Associated with genetic disorder: Gorlin syndrome, NF2
Most common sites of meningiomas include?
- Parasagittal regions of the Cerebral hemispheres
- Dura over the lateral con exits
- Olfactory groove etc
Can occur anywhere in the intracranium even within the ventricular system.
CmGross description of meningioma ?
- Usually well circumscribed
Encapsulated, smooth, rounded, bosselated, or polyploid mass. - usually attached to the dura, compressing underlying brain structures
Microscopic features of meningiomas
- Whorled pattern of arrangement of meningoepithelial cells
- presence of psammoma bodies (laminated, spherical calcospherites)
Histological variants of meningioma ?
Syncytial (meningothelial); whorled clusters of polygonal cells without visible cell membranes (syncytial) . With centrally placed nuclei
Fibroblastic; spindle shaped elongated cells which are arranged in interlacing or parallel bundles with abundant collagen deposition in between the cells
Transitional/mixed; features of both . Whorls pattern around a central capillary blood vessel
Center of some whorls may show psammoma bodies
Meningioma types (part 2)
- Psammomatous: Numerous psammoma bodies
- Secretory; contains gland like PAS positive eosinophilia secretions (pseudopsammoma bodies)
- Microcystic; microcystic soaces with a loose spongy appearance
- Angiomatous; numerous blood vessels
Immunohistochemistry for meningioma
GFAP negative
Keratin negative
Epithelial membrane antigen (EMA) positive
- WHO grade I/IV.
WHO grading of meningioma (1-3)
Majority of meningiomas are WHO grade 1
Grade 1
- meningothelial
- fibroblastic
- microcystic
- transitional
- psammomatous
- Angiomatous (hemangioblastic, angioblastic)
- secretory subtypes
- mataplastic
- lymphoplasmacyte rich
Grade 2 classification of meningioma
- Clear cell
- chordoid subtypes
-
Atypical by criteria
— 4 -19 mitotic figures
— Brain invasion
— Three of the following histological features
—— increased cellularity
—— small cells with high N/C ration
—— large and prominent nucleoli
—— patternless or sheet like growth
—— foci of spontaneous or geographic necrosis
Grade 3 classification of meningioma ?
- Rhabdoid
- Papillary subtypes
-
Anaplastic by criteria
—- 20 or more mitotic figures
—- display Frank sarcomatous or carcinomatous histology
Things that do not affect the grading of meningioma regardless?
- Invasion of dura, bone or soft tissue
- pleomorphic or atypical nuclei
- Ki67 is not a true diagnostic criteria (can be greater than 4% and uo 20%)
Immunochemistry of secretory meningioma?
- Psudoosammoma bodies are
- CEA positive
- Surrounding tumor cells - CEA, cytokeratin positive
- KLF4 K409Q and TRAF7 mutations
Clinical features do meningioma?
- Slow growing
- Produce symptoms by compressing underlying brain tissue and depend on site
Which brain tumors are commonly associated with the following. Histologic findings??
1) Rosenthal fibers and eosinophilic granular bodies - Pilocytic astrocytoma
2) Perivascular pseudorosettes - ependymoma
3) pseudopalisading necrosis - Glioblastoma
4) Homer wright rosettes- Medularryblastoma
5) Fried egg appearance and chicken wire vasculature - oligodendrocytoma
6) numerous psammoma bodies - **psammomatous meningioma
The most common primary site of tumors that metastasize to the brain are ?
- Lung
- Breast
- Skin (melanoma)
- Kidneys
- Gastrointestinal tract
Mostly carcinomas
Spread through the bloodstream
The most common intracranial neoplasms are?
Metastatic tumors
Choriocarcinoma has a high likelihood of mestasatsizing to ? And Protestant carcinoma ?
- The brain
- Prostate carcinoma almost never grow in the brain
Gross features of primary CNS tumors ?
- Sharply demarcated masses, surrounded by a prominent edmatous zone (boundary is sharp and well defined)
- usually seen at the junction of GM and WM
- microscopy - similar to that of the primary tumor
Central neurocytoma affects which part of the brain?
The intraventricular location
Tumors of pediatric age groups ?
Medulloblastoma
Pilocytic astrocytoma
Glioblastoma and lymphoma in older patients
