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Unit 8 > Tumors of CNS > Flashcards

Tumors of CNS Flashcards

1
Q

the metastases to the CNS includes

A
  • Metastases to the brain parenchyma
  • Neoplastic meningitis
  • metastasis to dura, skull, or spinal column
  • may cause seizures, confusion, coma and could lead to herniation and death
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2
Q

what are the characteristics of metastases to brain parenchyma?

A
  • usually multiple and 20% or less are single
  • usually well-circumscribed- do not infiltrate surrounding parenchyma
  • seen at junction between cerebral cortex and white matter (gray-white junction)
  • Primarily from Lung (70% of patients with small cell carcinoma of the lung will have brain metastases), breast, GI, renal cell, melanoma, thyroid, etc. Prostatic carcinoma infrequently metastasizes to the CNS
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3
Q

Neoplastic meningitis characterisitics

A
  • metastasis to leptomeninges-involves subarachnoid space
  • may see tumor cells in the CSF
  • Acute lymphoblastic leukemia (leukemic meningitis), non-hodgkin’s lymphoma, and carcinomas (particularly breast carcinoma) (carcinomatous meningitis)
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4
Q

paraneoplastic syndromes

A
  • rare group of disorders that have an immune response to tumor antigens that cross-react with CNS or PNS antigens
  • Antibodies include anti-hu, anti-yo
  • carcinomatous cerebellar degeneration-selective destruction of purkinje cells
  • limbic encephalitis: inflammation in the medial temporal lobe, chronic, resembles viral encephalitis
  • suacute sensory neuropathy: selective destruction of dorsal root ganglion neurons
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5
Q

Primary tumors of CNS I

A

-compression and/or edema (abnormal blood-brain barrier)- may lead to herniation
-benign tumors may lead to uncal or cerebellar tonsillar herniation, or both, resulting in death
-tumors histologically benign can kill, especially those that are located in regions of the brain or intracranial compartment that are difficult to approach neurosurgically
-tentorium separates cerebral hemispheres from brainstem and cerebellum
-Children: usually infratentorial compartment (cerebellum, brainstem, 4th ventricle)
-Adults: usually supratentorial compartment (especially cerebral hemispheres)
Clinical presentation: headache, seizures, progressive weakness (if tumor involves motor cortex)

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6
Q

what is the WHO grading system of primary tumors of CNS 1

A

I- benign
II- atypical
III- anaplastic (malignant)
IV- highly malignant (not allowed for some tumors, for which grade III is the highest)

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7
Q

Primary tumors of CNS II

A
  • meningiomas
  • gliomas
  • primitive neuroectodermal tumors (PNETS)
  • Primary brain lymphoma
  • other: craniopharyngioma, nerve sheath tumors (schwannoma)
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8
Q

what is the most common type of PNETS

A

medulloblastoma (tumor of the cerebellum)

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9
Q

Meningiomas

A
  • WHO grade I
  • More frequent in women and usually occur in middle age
  • on surface of the brain: arise from the arachnoid-leptomeningeal cells (attached to the dura) and histologically tries to recapitulate how the arachnoid looks
  • do not general infiltrate the brain but compress it
  • 25% recur after surgical excision: tricky to completely remove
  • mutation within tumor of NF2 gene on chromosome 22Q, or loss 22 or 22q - not usually used for diagnosis
  • histology: whirl like growth pattern of the cells trying to recapitulate the arachnoid, nuclei tend to be pale and maybe a little vacuolated, no mitoses becuase the tumors grows very slowly, calcifications and psammoma bodies
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10
Q

gliomas

A
  • astrocytomas: tumor cells often positive for glial fibrillary acidic protein (GFAP)
  • glioblastoma (GBM): tumor cells often have an astrocytic phenotype (highly malignant)
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11
Q

Oligodendroglioma

A
  • Oligodendroglioma: Slow-growing and have better prognosis than some of the other astrocytomas, calcifications, perinuclear halos (“fried egg” appearance)
  • Often calcifications
  • Can be WHO grade II or III (the latter is anaplastic oligodendroglioma)
  • For grade II or III, LOH or deletion of chromosomes 1p and 19q appears in some way to allow a better response to chemotherapy, i.e. better prognosis
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12
Q

Ependymoma is

A

intraventricular

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13
Q

what is the WHO grading of astrocytomas?

A
  • Grade I: pilocytic astrocytomas, other low-grade tumors
  • Grade II: well-differentiated diffuse astrocytomas
  • Grade III: anaplastic (malignant) astrocytomas
  • Grade IV: glioblastoma
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14
Q

what are features used for grading of astrocytomas

A
  • presence of necrosis- usually grade III or grade IV
  • mitotic activity: increased in higher grade tumors
  • cellularity- higher is worse
  • nuclear and cellular pleomorphism
  • microvascular or endothelial cell hyperplasia in the tumor
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15
Q

spread of gliomas

A
  • diffuse infiltration into surrounding parenchyma: difficult to resect
  • infiltration along white matter tracts
  • CSF dissemination
  • metastasis outside the CNS- rare
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16
Q

pilocytic (juvenile) astrocytoma

A
  • astrocytoma
  • occurs in children
  • most often arises in the cerebellum (cystic cerebellar astrocytoma) and may occur in the infundibulum
  • cystic with Rosenthal fibers
  • often excellent prognosis-WHO grade I
  • BRAF mutations often found in this tumor (either partial tandem duplication or specific point mutation V600E, diagnostically useful
  • Tumor cells are called pilocytic because they are hair-like
  • red structures in the cytoplasm of tumor cells are rosenthal fibers, which are used for diagnosis
17
Q

diffuse (fibrillary) astrocytoma

A
  • astrocytoma
  • WHO grade II
  • Tumor of adults and most common of the grade II astrocytomas
  • Cerebral white matter
  • Difficult to resect due to poorly defined margins and infiltration of surrounding parenchyma and often recur
  • may progress to higher grade glioma (glioblastoma)
  • present slowly with headaches and possibly slowly worsening neurological problems or seizures
  • 60% of diffuse astrocytomas have p53 mutation
  • cells have little processes and may have variable amounts of cytoplasm
  • IHC for GFAP shows the protein stained brown
18
Q

Glioblastoma (WHO grade IV)

A
  • highly malignant tumor: most common of the glioma group
  • arises most commonly in cerebral hemispheres in adults but can occur in other locations
  • Necrosis and hemorrhage
  • palisading necrosis: pseudopalisading tumor cells around necrotic zones
  • high cellularity, marked nuclear pleomorphism, mitoses
  • diffuse infiltration of surrounding brain by tumor cells
  • marked microvascular proliferation or endothelial cell hyperplasia due to expression of vascular endothelial cell growth factor (VEGF)
  • some retain astrocytic phenotype with GFAP positivity on immunocytochemistry
19
Q

Primary glioblastoma

A
  • arisen de novo: usually older people
  • about 2/3 of glioblastomas (more like 95%)
  • often have amplification of epidermal growth factor receptor (EGFR) gene and are negative for p53 mutations
  • may have loss of heterozygosity (LOH) of chromosome 10 or other changes
20
Q

Secondary glioblastoma

A
  • arisen from pre-existing, lower grade astrocytoma usually in younger adults
  • usually positive for p53 mutations and negative for EGFR amplification (not clinically important)
  • may have LOH or deletion of 19q or LOH of 10q
  • with IHC, you can see p53 accumulates in the nucleus
21
Q

Ependymoma

A
  • tumor that arises within the ventricle
  • WHO grade II
  • May spread by the CSF pathways but not as common as with medulloblastoma
  • usually no very invasive
  • in children, fourth ventricle
  • difficult to resect because of location
  • non-infiltrative with sharp border from surrounding parenchyma
  • may arise in spinal cord- need to differentiate because astrocytomas are infiltrative
  • histology: tries to recapitulate the ependymal and may have cilia
  • have a lot of cells that are GFAP positive because ependymal cells and astrocytic cells are closely related from an embryological point of view
22
Q

medulloblastoma

A
  • PNET which arises in the cerebellum
  • In children-midline (vermis)
  • In adolescents and adults-lateral cerebellum
  • CSF dissemination
  • May disseminate to leptomeninges
  • Radiosensitive but radiation is harmful to developing nervous system- standard treatment for children is chemotherapy
  • five year survival is 50% or more

Unit 8 (4 decks)

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