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62 Cards in this Set

  • Front
  • Back
Six types of astrocytic tumors (WHO)
1. Astrocytoma (diffuse)(II)
- fibrillary
- protoplasmic
- gemistocytic
- mixed
2. Anaplastic astrocytoma (III)
3. Glioblastoma (IV)
- giant cell glioblastoma
- gliosarcoma
4. Pleomorphic xanthoastrocytoma (II)
5. Pilocytic astrocytoma (I)
6. Subependymal giant cell astrocytoma (SEGA) of tuberous sclerosis (I)
WHO grade - astrocytic tumor with:
- nuclear atypia alone __
- nuclear atypia + mitotic activity __
- nuclear atypia + mitotic activity + endothelial proliferation and/or necrosis ___
- nuclear atypia alone (II)
- nuclear atypia + mitotic activity (III)
- nuclear atypia + mitotic activity + endothelial proliferation and/or necrosis (IV)
Note: the histopathologic heterogeneity ___ as the grade of the astrocytic tumor ___. Therefore small biopsies may preclude accurate __
- increases
- increases
- grading

- in a small biopsy, the presence of aytpia + necrosis would suggest a grade IV lesion, with unsampled mitotic activity
Two subtypes of glioblastoma based on a combination of clinical data with molecular genetic alterations.
1. primary (de novo) glioblastoma
- older patients (mean 62 yo)
- relatively short duration (months) without antecedent lower grade gliomas
- disturbance in p53/MDM2/p21 regulatory pathway via MDM2 gene amplification

2. secondary glioblastoma
- younger (mean 45 yo)
- history of lower grade gliomas
- disturbance in p53/MDM2/p21 regulatory pathway via TP53 gene abnormalities
Neoplastic gemistocytic astrocytes compared to reactive gemistocytes
- neoplastic cells have shorter, less conspicuous cytoplasmic processes
- neoplastic cells are closer together, lose respect for each other
The major astroglial marker is (IHC)___
- normal fibrillary and reactive astrocytes
- immature oligos
- reactive ependyma and choroid plexus epithelium

- MAJORITY of astrocytomas, EXCEPT protoplasmic astrocytomas (weak to negative GFAP)
- FOCAL AND/OR WEAK in anaplastic astrocytomas and GBM (due to limited differentiation)

- Vimentin (not specific) similar to GFAP
- S-100+ but not specific
- NSE+ but not specific
Fibrillary astrocytoma is the most common variant in the ___ of adults and the __ of children/adolescents
- cerebral hemispheres
- brainstem
Astrocytoma, gemistocytic variant tends to occur in a ___ age group compared to other astrocytomas. Unlike most supratentorial astroctyomas, gemistocytic variants may be grossly __ masses and have __ changes
- slightly older (50 vs 40 yo)
- grossly well-circumscribed mass
- cystic change (most astrocytomas are solid)
Should see at least __% gemistocytic astrocytes before calling the tumor a gemistocytic variant
- can see gemistocytic cells in fibrillary and anaplastic astrocytomas too!
Gemistocytic astrocytomas behave __, with __% progressing to glioblastoma
- aggressively
- 80%!
Protoplasmic astrocytomas are __ tumors (__% of astrocytomas). Most commonly located in ___ of ___.
- rare! (<1% astrocytomas)
- superficial cerebrum of children and young adults
With inadequate sampling, a pilocytic astrocytoma could be misinterpreted as a ___
protoplasmic astrocytoma

- the loose areas of a pilocytic look like a protoplasmic and its dense areas look like a fibrillary with Rosenthal fibers
In protoplasmic astrocytomas, GFAP staining is ___
scant to absent!!
WHO criteria for anaplastic astrocytoma include:
- Focally to diffuselly increased cellularity
- nuclear atypia
- mitotic activity

NO endothelial proliferation or necrosis present!!
__% of recurrent astrocytomas are likely to have progressed to anaplastic astrocyomas. However, some anaplastic astrocytomas present __

- de novo
Anaplastic astrocytomas have __ dense fibrillary matrix compared to fibrillary astrocytoma
less dense
- appreciated when preparing smears
There is a __ cell variant of anaplastic astrocytoma
small cell variant:
- aggressive tumor (median survival 6 mos)
- relatively bland cytologic features (mild pleomorphism)
- mimic histological features of an oligodendroglial neoplasm:
--nuclear homogeneity
--chicken wire-like capillaries
--clear perinuclear halo
--perineuronal satellitosis
GBM in adults most often occur in __, while in pediatric age group they occur most often in __
- cerebral hemispheres

- cerebellum and brainstem
On imaging, a GBM has a characteristic __
ring enhancement corresponding to areas of marked neovascularization and hypercellularity
Number of stereotactic biopsy that allow for accurate diagnosis and grading of GBM?
6 biopsy sites
Butterfly pattern on neuroimaging
GBM with distant spread along deep fiber tracts across the commissures to infiltrate the opposite hemisphere
Endothelial proliferation with glomeruloid-like vessels are seen in grade __ astrocytomas
- but this finding in a pilocytic astrocytoma is of no clinical significance
Tumor cells in a glioblastoma (features of)
- marked cytoplasmic and nuclear pleomorphism
- range from small closely packed atypical cells with scant cytoplasm and round to oval hyperchromatic nuclei to bizarre multinucleated cells
- most tumors have at least focal cells with obvious astrocytic features with delicate fibrillary processes
Glioblastomas can occasionaly demonstrate __ metaplasia
epithelial metaplasia with glandular formations!!! That can be CK+ and GFAP-

Can also see squmous features
Glomeruloid vascular proliferations with endothelial proliferation can be seen in the adjacent brain tissue next to a __

- biopsy of these areas show the charactersitic vascular formation without associated tumor (due to diffusion of VEGF type growth factors from the neoplastic astrocytes)

- warning
GBM may induce marked desmoplasia with leptomeningeal and dural invasion, NOT to be confused with __
EGFR amplification is seen in grade __ astrocytomas
III (10-20%) and IV (40%), NOT seen in any grade II
Giant cell glioblastoma differ from conventional glioblastoma
- short clinical history like a primary GBM in older pts, but these occur in younger pts!
- more favorable px w/ greater survival time
Giant cell glioblastoma is made up of __
-predominantly large, bizarre, multinucleate giant cells with abundant eosinophilic cytoplasm and large vesicular nuclei
- may be hard to find, but more fibrillary cells confirm the astrocytic nature of the tumor
- paucity of vascular endothelial proliferation
- increased reticulin fibers mostly around vessels
- large necrotic areas

- tumor giant cells are GFAP+ as are the more fusiform cells
Gliosarcoma accounts for __% of glioblastoma. Characterized by __

- biphasic tumor: glial component and a non-glial sarcomatous component
- significant component with mesenchymal differentiation
- may require GFAP to identify the neoplastic glial component
- sarcomatous component may exhbit: MFH, fibrosarcoma, osseous, chondroid, and rhabdomyosarcomatous features
Pilocytic astrocytomas are __ growing tumors, accounting for __ % of gliomas
pilocytic astrocytomas are the most common brain tumor in __
- 5-19 year age group
- most commonly present in first 2 decades of life
pilocytic astrocytomas are typically tumors of the ___ porition of the CNS
- cerebellum
- brainstem
- opitic chiasm/nerves
- ventricular region

- uncommon in the cerebral hemispheres (if so - predilection for temporal lobes and thalamus)
Pilocytic astrocytomas in the spinal cord tend to occur in __ (age group)
- older adults
Pilocytic astrocytomas __ diffusely infltrate surrounding neuropil and __ undergo progression to a high grade lesion
- do not
- rarely
SEGA, pilocytic and PXA are all __ tumors
well-circumscribed tumors
Pilocytic astrocytomas are characterized by a __ pattern (micro)
- a biphasic pattern
- dense areas with elongated, fibrillary, bipolar cells (piloid cells)
- loose areas with stellate cells with short processes (resemble protoplasmic astrocytes)
Piloid cells in pilocytic astrocytoma grow in bundles that tend to be accentuated about __

The stellate cells are associated with a __ pattern, with __ formation
- blood vessels

- lacy
- microcyst and cyst formation
Rosenthal fibers, granular hyaline droplets, and eosinophilic intracytoplasmic bodies are features characteristic of __ astrocytomas
pilocytic astrocytoma
- represent degenerative changes
Glomeruloid capillary and endothelial proliferations are ___ in pilocytic astrocytomas
- in this context, they do NOT imply malignant transformation as IS the case for anaplastic astrocytomas with these features
Pilocytic astrocytomas can display features that would be worrisome in a diffuse astrocytic tumor, but are okay in pilocytic tumors
- microvascular proliferation
- cellular atypia (nuclear atypia and pleomorphism)
- local invasion into leptomeninges without invasion into cerebrospinal pathways
- NO necrosis and NO significant mitotic activity
HOWEVER: combination of nuclear atypia, necrosis, and increased mitotic activity should arouse suspicion for anaplastic progression which can rarely occur in pilocytic astrocytomas
Monomorphous pilocytic astrocytoma are seen in ___ (age group) and typically located __
- infant/children
- hypothalalums, optic chiasm/nerve
- higher recurrence rate
- poor survival compared to conventional pilocytic astrocytomas
30% of pilocytic astrocytomas occur in patients with __, and these tumors occur at a younger age (mean 4.5 yo)
Pilocytic astrocytomas show a __ pattern of staining with GFAP
- fibrillary, piloid cells are strongly GFAP+
- stellate cells in the loose, microcystic areas are weakly GFAP+
Pleomorphic xanthoastrocytoma (PXA) are WHO grade __ tumors, althought they are __

- prognostically better than typical grade II (diffuse astrocytic) tumors
- less favorable than the well-diff grade I tumors

- relatively indolent tumors despite anaplastic features
PXA are uncommon tumors, <1% of astrocytic tumors; they occur in __ (age group) with a history of ___ and typically arise in the __
- children/young adults with a long history of seizures (2nd decade)
- supratentorial (most often temporal lobe)
Tumors with histologic features of a PXA but arising in other locations (besides supratentorial locations; temporal lobe) may not __
- have the same biologic behavior as the supratentorial tumors
PXA characteristically exhibit an __ cohesiveness
- increased
- due to increased reticulin stroma
- appreciated during smear prep
- good clue, because anaplastic astrocytomas are less cohesive and soft
Histologic features of a PXA
- moderately cellular
- pleomorphic cells, hyperchromatic nuclei, and xanthomatous giant cells
- few mitoses (NEVER abundant, compared to anaplastic astrocytomas with increased mitoses)[low MIB-1 index]
DDX for PXA includes__
1. anaplastic astrocytoma
- older age group
- mitotic activity
- less dense fibrillary matrix (soft)
- more aggressive tumors

2. lipidized glioblastoma
PXA in the temporal lobe are often ___ and may present as a __
- cystic
- mural nodule
PXA may grossly appear __ but microscopic __ is commonly present
- well-circumscribed (like SEGA and pilocytic astrocytoma)

- infiltration
GFAP and reticulin are __ in PXA
- see a rim of GFAP+ cytoplasm surrounding xanthomatous cytoplasm

increased reticulin matrix surrounding individual cells and cell clusters (firm tumor)
phakomatosis /phak·o·ma·to·sis/ (fak?o-mah-to´sis) pl. phakomato´ses any of a group of congenital hereditary developmental anomalies having selective involvement of tissues of ectodermal origin, which develop disseminated glial hamartomas; examples are neurofibromatosis, tuberous sclerosis, Sturge-Weber syndrome, and von Hippel-Lindau disease
A smear of a gliosarcoma whould demonstrate __
- a dual neoplastic population
- glial component detected by the fibrillary cytoplasmic processes at the edge of densely cellular areas
- sarcomatous component that lack a fibrillary background
In gliosarcoma, the glial component and the sarcomatous component are often __ delineated
Rosenthal fibers and granular eosinophilic bodies seen in __ are GFAP__
- pilocytic astrocytoma
SEGA occurs most often in the context of ___, however some occur without it.
tuberous sclerosus
SEGA typically present in ___(age group), as __
- children/young adults (frist two decades)

- well-circumscribed, often nodular, multicystic, lesion with calcifications

- Most often in wall of the LATERAL VENTRICLE at the level of basal ganglia, less commonly in the third ventricle

+/- symptoms due to obstruction of foramen of Monro
Tumor cells of a SEGA exhibit a wide spectrum of morphology
- polygonal cells with abundant, GLASSY cytoplasm
- elongated, smaller cells that are randomly oriented in a fibrillary matrix

- nuclei are vesicular with finely granular chromatin and distinct nucleoli

- ganglioid (neuron-like) cells are common
The tumors cells of SEGA are GFAP__, S-100__, and synaptophysin___

hybrid tumor
Presence of marked cellular/nuclear pleomorphism, increased mitoses, and occasional multinucleate cells, endothelial proliferation, and necrosis in a SEGA signify__
- nothing (acceptable)