Difference between revisions of "Neuropathology tumours"

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Neuropathology tumours (view source)

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==Pilocytic astrocytoma==
==Pilocytic astrocytoma==
===General===
{{Main|Pilocytic astrocytoma}}
*Low-grade astrocytoma.
*Classically in the cerebellum in children; most common glioma in children.<ref name=Ref_PSNP82>{{Ref PSNP|82}}</ref>
*The ''optic glioma'' associated with neurofibromatosis 1.
 
===Gross===
Features:<ref name=Ref_PSNP82>{{Ref PSNP|82}}</ref>
*Usually well-circumscribed.
*Cystic ''or'' solid.
*Do '''not''' smear. (Ref. ?)
 
===Microscopic===
Features:<ref name=Ref_PSNP82-4>{{Ref PSNP|82-4}}</ref>
*Classically biphasic (though either may be absent):
*#Fibrillar.
*#Microcystic/loose.
*Hair-like fibres ~ 1 micrometer; ''pilo-'' = hair.<ref>URL: [http://dictionary.reference.com/browse/pilo- http://dictionary.reference.com/browse/pilo-]. Accessed on: 24 November 2010.</ref>
**Best seen on smear or with GFAP [[IHC]].
*Rosenthal fibres - '''key feature'''.
**May be rare.  Not pathognomonic (see below).
*Eosinophilic granular bodies.
*Low cellularity - when compared to medulloblastoma and ependymoma.
 
Notes:
*+/-Microvascular proliferation.
*+/-Focal necrosis.
**Necrosis with pseudopalisading more likely glioblastoma.
*+/-Mitoses - not significant in the context of the Dx.
 
DDx (of Rosenthal fibers):<ref>MUN. 9 Mar 2009.</ref>
*Chronic reactive gliosis.
*Subependymoma.
*Ganglioma.
*Alexander's disease (rare leukodystrophy).
 
DDx of pilocystic astrocytoma (brief):
*Piloid gliosis.
*Oligodendroglioma.
*Glioblastoma (uncommon - but important).
 
Images:
*Smears:
**[http://commons.wikimedia.org/wiki/File:Pilocytic_astrocytoma_-_smear_-_very_high_mag.jpg Bipolar cells with hair-like processes - smear - very high mag. (WC)].
**[http://commons.wikimedia.org/wiki/File:Pilocytic_Micro.jpg EGBs - smear (WC/AFIP)].
**[http://commons.wikimedia.org/wiki/File:Rosenthal_fibers.jpg Rosenthal fibres - smear (WC/AFIP)].
*Sections:
**[http://commons.wikimedia.org/wiki/File:Rosenthal_HE_40x.jpg Rosenthal fibres (WC)].
**[http://moon.ouhsc.edu/kfung/jty1/neurotest/Q19-Ans.htm Rosenthal fibre (ouhsc.edu)].
**[http://path.upmc.edu/cases/case162.html Pilocytic astrocytoma (upmc.edu)].
**[http://path.upmc.edu/cases/case90.html Pilocytic astrocytoma - another case (upmc.edu)].
**[http://path.upmc.edu/cases/case195/images/figure3b.jpg Pilocytic astrocytoma - pennies on a plate (upmc.edu)].<ref>URL: [http://path.upmc.edu/cases/case195.html http://path.upmc.edu/cases/case195.html]. Accessed on: 8 January 2012.</ref>
**[http://path.upmc.edu/cases/case397.html Pilocytic astrocytoma (upmc.edu)].
 
===IHC/special stains===
Features:<ref name=Ref_PSNP84>{{Ref PSNP|84}}</ref>
*GFAP +ve (fibres).
*PAS-D: eosinophilic granular bodies +ve.
*CD68: may have a significant macrophage component.
*KI-67: may be "high" (~20% ???).
 
===Grading===
*''WHO Grade I'' by definition.


==Pleomorphic xanthoastrocytoma==
==Pleomorphic xanthoastrocytoma==
Michael
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