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11/1 Neuropathology of Brain Tumors
Neuro
56
Medical
Graduate
11/04/2011

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Term
brain herniations
Definition
3 main types of herniations occur in the brain

due to increased pressure - e.g. from a growing tumor

-subfalcine herniation of cingulate gyrus
-uncal herniation
-transforaminal herniation of cerebellar tonsil
Term
uncal herniation
Definition
transtentorial herniation of middle part of temporal lobe
Term
tumor growth in infants
Definition
because the skull sutures haven't close, the tumor can grow unrestricted and herniation is much less likely
Term
classification names of CNS tumors
Definition
-meningeal
-glial
-embryonal
-neuronal
-tumors of CN and PN
-hematopoietic
Term
histological grading of tumors
Definition
correlates with biologic behavior of a tumor

it is a key factor in choosing therapeutic alternative (surgery, radiation, chemo)

*WHO grades I-IV*
Term
*WHO Grade I*
Definition
low proliferative potential

usually slow growing

possibility of cure with surgical resection alone
Term
*WHO Grade II*
Definition
generally infiltrative

often recur

may progress to higher grades with time
Term
*WHO Grade III*
Definition
histological evidence of malignancy (e.g. nuclear atypia, brisk mitotic activity)

patients will often receive adjuvant radiation and/or chemotherapy
Term
*WHO Grade IV*
Definition
cytologically malignant, mitotically active, necrosis

often associated with rapid pre-postoperative evolution and fatal outcome
Term
meningioma
Definition
usually slow growing tumors; brain adapts around it

arise from meningothelial cells in the leptomeninges (pia mater and arachnoid mater)

intraspinal meningiomas F>M 10:1

often attached to the dura (may see dural tail)
Term
meningioma

associations
Definition
previous radiotherapy

hormonal dependent neoplasms (breast, endometrial)

neurofibromatosis type 2
Term
meningioma

histological features
Definition
syncytial growth

whorl formation

intranuclear inclusions

psammoma bodies (laminated, calcified)
Term
grading of meningioma
Definition
most are grade I with 7-25% of recurrence
-complete resection is the most important factor to prevent recurrence

grade II and III meningiomas exist and have high recurrence rates; usually require adjuvant radiation/chemo
Term
types of glial tumors
Definition
astrocytic

oligodendroglial

ependymal
Term
astrocytic glial tumors
Definition
two categories:

Circumscribed - grade I, II

Inflitrative - grade II, III, IV
Term
circumscribed astrocytic glial tumor
Definition
WHO grade I or II

can be completely excised withOUT a high likelihood of recurrence

-->Pilocytic Astrocytoma
Term
pilocytic astrocytoma

epidemiology
locations
Definition
astrocytic, circumscribed, glial tumor, WHO grade I

*mainly in children and young adults*

cerebellum, optic nerve, optic chiasm/hypothalamus, temporal lobe

associated with neurofibromatosis type I
Term
pliocytic astrocytoma

histological features
Definition
hair-like processes

*Rosenthal fibers* dense fibers in compact area

biphasic and micro cystic change - compact & loose areas
Term
infiltrative astrocytic glial tumor
Definition
WHO grades II, III, IV

II: diffuse astrocytoma*
III: anaplastic astrocytoma
IV: glioblastoma
Term
infiltrative astrocytic glial tumor

histological features
Definition
micro cysts

perineuronal satellitosis (cells around neurons)

perivascular satellitosis

subpial aggregates

white matter tract infiltration
Term
diffuse astrocytoma

characteristics/location
Definition
infiltrative astrocytic glial tumor, WHO grade II

slow growth; preferentially supretentorial (in cerebrum); tendency to progress; non-enhancing lesions
Term
diffuse astrocytoma

mean age of diagnosis
Definition
mean age of dx = 34 years
Term
diffuse astrocytoma

histo
Definition
mild increase in cellularity compared to normal brain
Term
anaplastic astrocytoma

characteristics/location
Definition
infiltrative astrocytic glial tumor, WHO grade III

most common in cerebral hemispheres

2/3 enhancing lesions
Term
anaplastic astrocytoma

mean age of diagnosis
Definition
mean age of dx = 45 years
Term
anaplastic astrocytoma

histo
Definition
hyper cellularity

nuclear atypia; more pleomorphic nuclei

significant proliferative activity
Term
glioblastoma

characteristics
Definition
infiltrative astrocytic glial tumor, WHO grade IV

ring enhancing with central necrosis

poor prognosis, improving with new therapies
Term
glioblstoma

mean age of diagnosis
Definition
mean age of dx = 61 years

most frequent brain tumor in adults
Term
glioblastoma

histo
Definition
microvascular proliferation

necrosis

butterfly lesion

most cellularity
Term
pathologic progression/development of infiltrating astrocytomas
Definition
astrocytes or precursor stem cells can differentiate directly into a primary/de novo glioblastoma or go through a progression starting with low-grade astrocytoma and going onto either a secondary glioblastoma or a anaplastic astrocytoma and then secondary glioblastoma
Term
oligodendroglial glial tumors

epidemiology
Definition
uncommon in childhood

occur most frequently in patients aged 30-50 years
Term
oligodendroglial glial tumor

characteristics
Definition
more prone to hemorrhage than other gliomas

WHO grade II and III, but in general better prognosis than the same grade astrocytoma
Term
oligodendroglial glial tumor

histologic features
Definition
infiltrative

round nuclei
>fried egg appearance
perinuclear halos

fine branching blood vessels

many have micro calcifications
Term
*molecular aspects of oligodenrogliomas*
Definition
*loss of 1p (short arm on chromosome 1)
*loss of 19q (long arm on chromosome 19)

*better response to chemo and better survival reponse with loss of 1p and 19q
Term
ependymal glial tumor
Definition
WHO grades I, II, III

grade II: classic ependymoma

grade III: anaplastic ependymoma
Term
classic ependyoma & anaplastic ependyoma

characteristic/location
Definition
grade II (classic) and III (anaplastic) ependyoma glial tumors

intracranial neoplasm of childhood

intraventricular

most common in posterior fossa

*well-circumscribed
Term
classic ependyoma & anaplastic ependyoma

mean age
Definition
mean age = 4 years

present with increased ICP, hydrocephalus
Term
ependyoma glial tumors

histo
Definition
psuedorosettes = tumor aligns along blood vessel

ependymal rosettes and canals
Term
embryonal CNS tumors
Definition
medulloblastoma
Term
medulloblastoma
Definition
-embryonal CNS tumor
-primarily in children
-tendency to disseminate through CNS
-generally arises from the vermis and fills the 4th ventricle
-presents as increased intracranial pressure symptoms
*WHO grade IV
-rapidly fatal if untreated
-current therapy achieves 5 yeah PFS (progression-free survival) of 50-80%
Term
medulloblastoma

histo
Definition
small, undifferentiated cells

high mitotic index and widespread apoptosis

may form Homer Wright rosettes
Term
tumors of CN and PN
Definition
Schwannoma

neurofibroma

MPNST
Term
Schwannoma
Definition
-neurilemmona; acoustic neuroma
-Schwann cells proliferate and push away axon
-discrete contrast enhancing +/- cystic
-bilateral acoustic schwannomas associated with type 2 neurofibromatosis
-do not infiltrate the nerve of CNS
-WHO grade I
Term
Schwannoma

histo
Definition
verocay bodies

Antoni A and B areas
-areas of hyper/hypocellularity

basal membrane deposition
Term
neurofibroma
Definition
infiltrate the nerve

WHO grade I

plexiform NF affects large plexus

10% have malignant transformation
Term
neurofibroma

histo
Definition
hypocellular lesion

proliferation of: Schwann cells, perineurial cells, fibroblasts, blood vessels, mast cells

spindle nucleus Schwann cells mixed with other cells
Term
malignant peripheral nerve sheath tumor
MPNST
Definition
usually arises from pre-existing plexiform neurofibroma

associated with prior radiation

WHO grade III or IV

3rd-6th decode of life
Term
MPNST

histo
Definition
sarcoma looking

geographic necrosis

high mitotic activity
Term
hematopoietic CNS tumors
Definition
primary CNS lymphomas
Term
primary CNS lymphoma
Definition
occurs sporadically and in immunocompromised patients

**EBV plays an important role of development in 95% of immunocompromised patients**

forms a large, enhancing intraparenchymal mass; may be multicentric

(lymphomas which arise outside the NS may infiltrate meninges, but usually do not form masses)
Term
primary CNS lymphoma

histo
Definition
often show angiocentric growth

tumor cells have big nuclear:cytoplasm ratio

cells are dyshesive

monoclonal proliferation of lymphoid cells, most often B-cells

nuclei arrange around vessels and infiltrate out
Term
metastatic tumors to the CNS
Definition
usually develop from hematogenous spread
-lung, breast, renal, colon carcinomas
-melanoma

rarely by direct extension (head and neck)

often multiple, in the gray/white junction or meninges

form a distinct margin with adjacent brain
Term
which tumors are WHO grade I
Definition
pilocytic astrocytoma
myxopapillary ependymoma
Scwannoma
neurofibroma
Term
which tumors are WHO grade II
Definition
astrocytomas
oligodendroglioma (fried egg, 1p19q)
classic ependymoma
Term
which tumors are WHO grade III
Definition
anaplastic astrocytoma
anaplastic ependymoma
Term
which tumors are WHO grade IV
Definition
glioblastoma (malignant)
medulloblastoma (small round blue cell tumor)
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