Tumors Flashcards
Where are a majority of childhood primary brain tumors located
Cerebellum & brainstem
In adults what is the most common tumor of the CNS
glioblastoma
In children what is the most common tumor of the CNS
Embryonal
Describe the grading of brain tumors
Grade I - low proliferative potential
Grade II - Infiltrative (likely to recur)
Grade III - Radiation chemo (anaplasia & mitoses)
Grade IV - Fatal outcome (necrosis & microvascular proliferation)
What are the four histological parameters of gliomas
Nuclear atypia
Mitoses
Microvascular proliferation
Necrosis
If someone has an oligodendroglioma what is the grade
II/IV unless it is anaplastic then it is III/IV
Where do astrocytomas usually develop
White matter
in SC can present as CN VI dysfunction
Describe pilocytic astrocytomas
first two decades of life
appear in cerebral hemispheres for adults and cerebellum for children
NF1 predisposes
Well circumscribed often cystic with mural nodule
Describe the histology of pilocytic astrocytomas
Biphasic patterns (loose glial with cystic changes & dense piloid tissue)
Hair like cells with long bipolar processes
Rosenthal fibers
Eosinophilic granular bodies
Describe glioblastomas
most common primary brain neoplasm
Contrast ring enhancing, with hypodense central necrosis
Differentiate primary vs secondary glioblastoma
primary: later in life no precursor lesion
secondary low grade (TP53) lesion. IDH1 better prognosis than IDH2
what are the three histology hallmarks of glioblastoma
Necrosis (serpentine)
Pseudopalisading
Vascular/endothelial proliferation
Describe Oligodendroglioma
10-15% of all gliomas, primarily in adults
Calcification restricted to cortex
on histo: perinuclear (fried egg halos); chicken wire anastomosing capillaries
Describe ependymomas
first two decades of life
fourth ventricle most common site, spinal for adult
on histo looks like scream painting
What are ependymal rosettes
true rosette: tubular structure with central canal; more diagnostic than perivascular rosettes
What embryonal tumor makes up 20% of tumors in children
medulloblastoma
What are the 4 molecular GRPS
WNT (older kids, monosomy 6, B-catenin 90% survival 5 yrs)
SHH (infants -young adults)
MYC (infants and children Worst progrosis)
Group 4 17q. no MYC +/- MYCN poor prognosis
Describe atypical teratoid/rhabdoid tumor
Posterior fossa or supratentorial
Divergent differentiation
Rhabdoid cells: eosinophilic cytoplasm with sharp boarders & eccentric nucleus, resemble Rhabdomyosarcoma
> 90% have chr 22; HSNF5/INI1
<1 year survival
Describe the etiology of primary CNS lymphoma
Immunosuppressed individuals (AIDS) B-cell origin CD20 aggressive with EBV
Accumulate around vessels = hooping
What is the most common pineal tumor
Germinoma of the pineal body.
pineocytoma: well differentiated LG in adults
pineoblastoma: high grade necrosis mitoses HG kids (RB gene spreads throughout CNS)
Why do meningiomas develop rapidly in pregnant women?
70% express progesterone receptors and will ballon during pregnancy
What are the most common places to have tumors metastasize from to reach the brain
Lung Breast Melanoma Kidney GI
Meninges is common site of met
Describe cowden syndrome
Dysplastic gangliocytoma PTEN -> IK3/AKT signaling mutation
Describe Li-Fraumeni syndrome
Medulloblastomas; mutations in TP53
Describe Turcot syndrome
MEdulloblastoma or Glioblastoma
Mutations in APC or mismatch repair genes
Describe Gorlin Syndrome
Medulloblastoma
mutations in PTCH -> upreg of SHH
Describe Neurofibromatosis NF, type 1
Common
neurofibromas
Optic nerve gliomas
Lisch nodules
Cafe au lait spots
Describe NF type 2
Less common
BL schwannomas (CN VIII)
increased meningiomas ependymomas
