Primary Brain Cancer
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- Most common form of primary brain cancer.
- meningioma
- Most common primary tumor in children
- Medulloblastoma
- Which population are menigiomas more common?
- women and older populations
- Meningiomas are commonly seen in this genetic disease.
- NF-2
- Menigiomas arise from which cells?
- arachnoid cap cells
- Histiologic appearance of meningiomas.
- whorls of tightly packed cells around calcified acellular material called psammoma bodies
- Primitive neuroectodermal tumors (PNETs) usually arise ?
- posterior fossa
- Medulloblastoma can metastasize to ?
- bone
- Symptoms of PNETs?
- related to mass effect in posterior fossa: ataxia, balance and equilibrium disturbances, cranial nerve palsies
- Which pathway may be involved in the development of medulloblastomas?
- Sonic Hedgehog
- Histological appearance of medulloblastoma.
- prominent nuclei w/ little cytoplasm; very uniform sheets of cells
- Oligodendrogliomas are often ___ and patients often present with ___.
- calcified, seizures
- Oligodendrogliomas are more ____ based as opposed to astrocytomas which are ____.
- cortically, deeper
- Histology of oligodendrogliomas.
- "fried egg" appearance, very fine vascular pattern described as a chicken wire appearance
- Loss of what parts of chromosomes is associated w/ oligodendrogliomas and portends a favorable prognosis.
- 1p and 19q
- The majority of primary CNS lymphomas fall into the ____ category
- large B cell
- Treatment of CNS lymphoma:
- methotrexate to inhibit dihydrofolate reductase; leukovorin rescues purine synthesis pathway in the rest of the body
- Which CNS neoplasm is the most malignant?
- Astrocytoma (type IV, GBM)
- Histologically the main difference between grade III and grade IV astrocytomas.
- necrosis and neovascularizaiton
- If this gene is silenced by methylation then a patient will respond better to treatment with temozolomide.
- MGMT
- De novo GBM is associated with amplification of ___ and loss of ___.
- EGFR, PTEN
- Intermediate filament found in the cytoplasm of normal astrocytes, reactive astrocytes, and astrocytic tumors.
-
GFAP
"Good For Astrocyte Peeking" - Grade II and III frequently have a mutation in ___.
- p53
- Viable tumor cells around necrosis; seen in GBM.
- pseudopallisading necrosis
- Better prognosis: Secondary or Primary GBM?
- Secondary, but still poor
- Mutations in Secondary GBM
- p53 & Rb loss
- Mutations in Primary GBM
- EGFR amplification, p16 deletion, PTEN deletion
- Typical histological finding in ependymal tumors
- rosettes around blood vessels
- Defective oncogene seen in sporadic menigiomas.
- merlin from monosomy of chromosome 22
- Histological appearance of CNS lymphoma.
- Angiocentric pattern, with lymphocytes expanding hte Virchow-Robin space
- Most common CNS tumor in children.
- Piliocytic Astrocytoma
- Acellular eosinophilic material with a glassy appearance often found in pilocytic astrocytomas.
- Rosenthal fibers
- Tumor cells surround acellular material, seen in medulloblastomas.
- Homer-Wright rosettes
- Benign tumors found in the sella turcica, compress the pituitary and optic chiasm.
- Craniopharyngiomas
- Histology of craniopharyngiomas.
- Multiple cysts. Tumor cells show evidence of squamous differentiation w/ keratin formation.
- PNS, numerous Schwannomas and subcutaneous neurofibrommas.
- NF-1 (Von Recklinhausen's disease)
- NF-1 inheritence.
- Autosommal dominant
- NF-1 is due to ______/
- Deletion of gene on chromosome 17 for protein that inactvates Ras.
- Difference between neurofibroma and Schwannoma.
- Schwannoma only involves some of the nerve rootlets. Neurofibroma is more invasive and whole nerve will be sacrificed.
- CNS, bilateral acoustic Schwannomas, increased incidence of astrocytomas and meningiomas.
- NF-2
- NF-2 caused by deletion of gene ____.
- merlin on chromosome 22.
- Visceral schwannomas and neurofibromas and of adrenal gland.
- NF-3
- Inheritence of NF-2
- Autosommal dominant.
- Histology of schwannoma.
- Elongated nuclei, stack on top of each other forming Antoni type A or Verocay bodies.
- Two genes involved in tuberous sclerosis:
- TSC-1 on chromosome 9 (hamartin) and TSC-2 found on chromosome 16 (tuberin)
- Inheritence of tuberous sclerosis:
- AD
- Lesions seen in Tuberous Sclerosis:
- glial hamartomas, subpendymal giant cell astrocytomas
- Common location of schwannomas.
- cerebellar pontine angle involving CN VIII
- Common clinical presentation of an astrocytoma.
- headache
- Two tumors from neural CREST origin.
- menigiomas and schwannomas
- Where are more pediatric brain tumors distributed compared to adult brain tumors?
- posterior fossa
- What is the importance of doing a T1 MRI WITH CONTRAST?
- contrast can get to areas where the BBB has been breeched (e.g. a tumor!)
- Imaging of low grade astrocytoma.
-
CT- low density, non enhancing
MRI - iso/hypointense on T1, hyperintense on T2
PET - hypometabolic - Imaging of Grade III astrocytoma.
-
CT - frequent mass effect
MRI - inhomogeneity, T2 diffuse area of edema
PET - hypermetabolic - Imaging of GBM.
-
CT & MRI - inhomogenous T2 hyperintense, hetergeneously enhancing b/c of necrosis
PET - hypermetabolic - Imaging of meningioma.
-
CT - iso/hypointense, homogenous, can be calcified
MRI - iso/hypointense on T1, variable on T2 - Imaging of metastases.
-
CT - discrete and noninfiltrative, edema
MRI - low attenuation on T1, little attenuation on T2, often cystic or necrotic center
PET - hypermetabolic - Imaging of medulloblastoma.
-
CT - iso/hypointense w/ edema, homogenous
MRI - hypointense on T1, variable on T2, 4th ventricular extension - Positive prognostic factors for higher grade astrocytomas.
-
Grade III better than IV.
Younger patients do better.
Healthier patients do better - Whole brain radiotherapy is appropriate in patients with greater than ____ metastatic lesions.
- 3
- Gold standard to determine between a tumor and radiation necrosis.
- resection/biopsy
- What is used to prevent seizures during interoperative mapping?
- iced ringers lactate
- Balloon filled with radioactive liquid placed in the brain.
- Brachytherapy
- Gamma knife is most often used for which tumors?
- metastatic brain tumors
- Which cancer has the highest propensity to metastasize to the brain?
- Melanoma