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
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
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)
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
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)
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)
7
Q
Primary tumors of CNS II
A
- meningiomas
- gliomas
- primitive neuroectodermal tumors (PNETS)
- Primary brain lymphoma
- other: craniopharyngioma, nerve sheath tumors (schwannoma)
8
Q
what is the most common type of PNETS
A
medulloblastoma (tumor of the cerebellum)
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
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)
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
12
Q
Ependymoma is
A
intraventricular
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
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
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
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
