Difference between revisions of "Neuropathology tumours"

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[[Image:Gemistocytic Astrocytoma 003.jpg|thumb|right|A brain stem [[astrocytoma]]. (WC)]]
The article covers '''tumours in neuropathology'''.  Tumours are a large part of [[neuropathology]].  [[Cytopathology]] of CNS tumours is dealt with in the article ''[[CNS cytopathology]]''.
The article covers '''tumours in neuropathology'''.  Tumours are a large part of [[neuropathology]].  [[Cytopathology]] of CNS tumours is dealt with in the article ''[[CNS cytopathology]]''.


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==Brain tumours - overview==
==Brain tumours - overview==
===Adult===
===Alphabetical===
For overview see [[:Category:Neuropathology_tumours|here]]
 
===By age group===
====Adult====
Four most common types of brain tumours:<ref>[http://neurosurgery.mgh.harvard.edu/abta/primer.htm http://neurosurgery.mgh.harvard.edu/abta/primer.htm]</ref>
Four most common types of brain tumours:<ref>[http://neurosurgery.mgh.harvard.edu/abta/primer.htm http://neurosurgery.mgh.harvard.edu/abta/primer.htm]</ref>
# Metastatic brain tumours (barely edges out primary tumours)
# Metastatic brain tumours (barely edges out primary tumours)
Line 11: Line 16:
#*[[Melanoma]].  
#*[[Melanoma]].  
#*[[Renal cell carcinoma]] (RCC).
#*[[Renal cell carcinoma]] (RCC).
# [[Glioblastoma]] (previously known as ''glioblastoma multiforme'').
# [[Glioblastoma]], IDH-wildtype.
# [[Anaplastic astrocytoma]].
# [[Astrocytoma, IDH-mutant]].
# [[Meningioma]].
# [[Meningioma]].


===Children===
====Children====
# Astrocytoma.
# [[Pilocytic astrocytoma]].
# Medulloblastoma.
# [[Medulloblastoma]].
# Ependymoma.
# [[Ependymoma]].
# Pontine glioma, often [[Diffuse midline glioma, H3 K27-altered]].


===Location (most common)===
===By location===
Certain tumours like to hang-out at certain places:<ref>URL: [http://www.msdlatinamerica.com/ebooks/DiagnosticNeuropathologySmears/files/4ce563fb7e8e48fc9ed8b42e296a7747.gif http://www.msdlatinamerica.com/ebooks/DiagnosticNeuropathologySmears/files/4ce563fb7e8e48fc9ed8b42e296a7747.gif] and [http://www.msdlatinamerica.com/ebooks/DiagnosticNeuropathologySmears/sid117213.html http://www.msdlatinamerica.com/ebooks/DiagnosticNeuropathologySmears/sid117213.html]. Accessed on: 2 November 2010.</ref>
Certain tumours like to hang-out at certain places:<ref>URL: [http://www.msdlatinamerica.com/ebooks/DiagnosticNeuropathologySmears/files/4ce563fb7e8e48fc9ed8b42e296a7747.gif http://www.msdlatinamerica.com/ebooks/DiagnosticNeuropathologySmears/files/4ce563fb7e8e48fc9ed8b42e296a7747.gif] and [http://www.msdlatinamerica.com/ebooks/DiagnosticNeuropathologySmears/sid117213.html http://www.msdlatinamerica.com/ebooks/DiagnosticNeuropathologySmears/sid117213.html]. Accessed on: 2 November 2010.</ref>
*Cerebrum:
====Cerebrum====
**Cortical based - [[oligodendroglioma]].
*Cortical based - [[oligodendroglioma]].
**Grey-white junction - metastases.
*Grey-white junction - metastases.
**White matter - astrocytoma, [[glioblastoma]].
*White matter - astrocytoma, [[glioblastoma]].
**Periventricular - CNS lymphoma.
*Periventricular - CNS lymphoma.
**Cystic - [[ganglioglioma]], [[pilocytic astrocytoma]], [[pleomorphic xanthoastrocytoma]].
*Cystic - [[ganglioglioma]], [[pilocytic astrocytoma]], [[pleomorphic xanthoastrocytoma]].
*Cerebellum:
====Cerebellum====
**Midline/central - [[medulloblastoma]].
*Midline/central - [[medulloblastoma]].
**Cystic lesion - pilocytic astrocytoma (younger individual), [[hemangioblastoma]] (older individual).
*Cystic lesion - pilocytic astrocytoma (younger individual), [[hemangioblastoma]] (older individual).
**Solid lesion (older individual) - metastasis.
*Solid lesion (older individual) - [[metastasis]].
*Spinal cord:
====Sella turcica====
**[[Ependymoma]], glioblastoma.
* [[Pituitary adenoma]].
**Filum terminale - [[myxopapillary ependymoma]], [[paraganglioma]].
* [[Craniopharyngioma]].
 
less common:
* [[Pituicytoma]].
* [[Granular cell tumour]].
* [[Germinoma]].
* [[Chordoma]]
* Rathke cleft cyst.
* Hypophysitis.
* Xanthogranuloma.
====Spinal cord====
*[[Ependymoma]]
*[[Glioblastoma]]
*[[Meningioma]]
*Carcinoma metastasis
*[[Hemangioblastoma]]
====Filum terminale====
====Filum terminale====
*Filum terminale = bottom end of the spinal cord - has a limited differential.
DDx:<ref>JLK. 31 May 2010.</ref>
*[[Meningioma]].
*[[Meningioma]].
*[[Myxopapillary ependymoma]].
*[[Myxopapillary ependymoma]].
*[[Neurofibroma]].
*[[Neurofibroma]].
*[[Schwannoma]].
*[[Schwannoma]].
*Paraganglioma.
*[[Paraganglioma]].
 
====Meninges====
====Cerebellopontine angle====
* [[Meningioma]].
DDx:<ref>R. Kiehl. 8 November 2010.</ref>
* [[Solitary fibrous tumour]] / Hemangiopericytoma.
*Schwannoma.
* [[Hemangioblastoma]].
*[[Meningioma]].
less common:
*[[Dermoid cyst]]/epidermoid cyst.
* [[Melanoma]] / Melanocytoma.
*Ependymoma.
* Lymphoproliferative diseases.
*[[Choroid plexus papilloma]].
* [[Sarcoidosis]]
* [[Arachnoid cyst]].
* Disseminated oligodendroglial-like leptomeningeal tumour.
* Desmoplastic infantile astrocytoma / ganglioglioma.
* Meningioangiomatosis.
* Calcifying pseudoneoplasm.
====Skull====
* [[Fibrous dysplasia]].
* [[Paget disease]].
* [[Histiocytosis]].
* [[Hemangioma]].
* [[Aneurysmal bone cyst]].
* [[Plasma_cell_neoplasms#Multiple_myeloma|Multiple myeloma]].
====Skull base / Cerebellopontine angle====
* [[Schwannoma]].
* [[Meningioma]].
* [[Dermoid cyst]] / epidermoid cyst.
less common:
* [[Ependymoma]].
* [[Choroid plexus papilloma]].
* [[Glomus tumour]].
* [[Chordoma]].
* [[Chondrosarcoma]].
* [[Olfactory neuroblastoma]].
* [[Endolymphatic sac tumour]].


===Cystic tumours===
===Primary versus secondary===
DDx:<ref>URL: [http://path.upmc.edu/cases/case320/dx.html http://path.upmc.edu/cases/case320/dx.html]. Accessed on: 14 January 2012.</ref>
*[[AKA]] (primary) brain tumour versus metastatic cancer.
*[[Pilocytic astrocytoma]].
*[[Pleomorphic xanthoastrocytoma]].
*[[Ganglioglioma]].
*[[Hemangioblastoma]].
*[[Craniopharyngioma]].<ref>URL: [http://www.pathologyoutlines.com/Cnstumor.html#cystsgeneral http://www.pathologyoutlines.com/Cnstumor.html#cystsgeneral]. Accessed on: 14 January 2012.</ref>
 
===Primary vs. secondary (metastatic)===
====Primary====
====Primary====
Glial tumours:
[[Glioma|Glial tumours]]:
*Cytoplasmic processes - '''key feature'''.
*Cytoplasmic processes - '''key feature'''.
**Best seen at highest magnification - usu. ~1 micrometer.
**Best seen at highest magnification - usu. ~1 micrometer.
**Processes may branch.
**Processes may branch.
*Ill-defined border/blend with the surrounding brain.
*Ill-defined border/blend with the surrounding brain.
[[Meningioma]]:
*Lesion often dura-based.
*Mesenchymal tumor (often contains collagen).


[[Lymphoma]]:
[[Lymphoma]]:
*Primary CNS Lymphoma (PCNSL) is usu. a diffuse large B-cell lymphoma.
*Large (lymphoid) cells, ergo usu. not a difficult diagnosis.
*Large (lymphoid) cells, ergo usu. not a difficult diagnosis.
**~2x size of resting lymphocyte, nucleoli.
**~2x size of resting lymphocyte, nucleoli.
*Lesion predominantly perivascular.  
*Lesion predominantly perivascular.


====Secondary====
====Secondary====
Carcinomas:
*Carcinomas:
*Well-demarcated border between brain and lesion - '''key feature'''.
**Well-demarcated border between brain and lesion - '''key feature'''.
*No cytoplasmic processes.
**No cytoplasmic processes.
*Usu. have nuclear atypia of malignancy.
**Usu. have nuclear atypia of malignancy.
**Nuclei often ~3-4x the size of a [[RBC]].
**Nuclei often ~3-4x the size of a [[RBC]].
*+/-Glandular arrangement.
**+/-Glandular arrangement.
*+/-Nucleoli.
**+/-Nucleoli.
*Melanoma.
*Secondary Lymphoma.
*Sarcomas (rare).
 
===By growth pattern===
====Infiltrative astrocytomas====
*[[Astrocytoma, IDH-mutant]].
*[[Glioblastoma]], IDH-wildtype.
 
Notes:
**Glial: "blends into brain"/gradual transition to non-tumour brain.
 
====Non-infiltrative astrocytomas====
**[[Pilocytic astrocytoma]]
**[[Pleomorphic xanthoastrocytoma]]
**[[Subependymal giant cell astrocytoma]].
 
====Cystic tumours====
DDx:<ref>URL: [http://path.upmc.edu/cases/case320/dx.html http://path.upmc.edu/cases/case320/dx.html]. Accessed on: 14 January 2012.</ref>
*[[Pilocytic astrocytoma]].
*[[Pleomorphic xanthoastrocytoma]].
*[[Ganglioglioma]].
*[[Hemangioblastoma]].
*[[Craniopharyngioma]].<ref>URL: [http://www.pathologyoutlines.com/Cnstumor.html#cystsgeneral http://www.pathologyoutlines.com/Cnstumor.html#cystsgeneral]. Accessed on: 14 January 2012.</ref>
 
 
Notes:
**Non-glial: no radiating glial processes.
*Rosenthal fibres within the tumour... often seen in [[pilocytic astrocytoma]].
**Rosenthal fibres may be seen around a (very) slow growing tumour and represent a reactive process.
*Inflammatory cells and macrophages should prompt consideration of an alternate diagnosis (e.g. [[cerebral infarct]], [[multiple sclerosis]]) - esp. if this is a primary lesion.<ref>URL: [http://path.upmc.edu/cases/case79/dx.html http://path.upmc.edu/cases/case79/dx.html]. Accessed on: 2 January 2012.</ref>
 
====Grading====
Nuclear pleomorphism present:
*At least grade II (diffuse astrocytoma).
 
Mitotic figures present:
*At least grade III (anaplastic astrocytoma).
 
Microvascular proliferation ''or'' necrosis with pseudopalisading tumour cells:
*Grade IV (glioblastoma [[AKA]] glioblastoma multiforme).
 
Notes:
*Pseudopalisading tumour cells = high tumour cell density adjacent to regions of necrosis; palisade = a fence of poles forming a defensive barrier or fortification.
*WHO Grading is currently based on expected biologiocal behaviour without treatment.
**Grading does not reflect molecular divergent groups within a tumor class  or response to therapy (Currently controversies in grading for IDH-mutant astrocytoma vs. IDH-wildtype astrocytoma).<ref>{{Cite journal  | last1 = Louis | first1 = DN. | last2 = von Deimling | first2 = A. | title = Grading of diffuse astrocytic gliomas: Broders, Kernohan, Zülch, the WHO… and Shakespeare. | journal = Acta Neuropathol | volume =  | issue =  | pages =  | month = Aug | year = 2017 | doi = 10.1007/s00401-017-1765-z | PMID = 28801693 }}</ref>
 
===By IHC===
*GFAP - should stain cytoplasm of tumour cells and the perikaryon (nuclear membrane) of most [[Astrocytoma]]s.
*[[IDH-1]](R132H) (isocitrate dehydrogenase 1) in [[Astrocytoma, IDH-mutant]].<ref name=pmid19228619>{{cite journal |author=Yan H, Parsons DW, Jin G, ''et al.'' |title=IDH1 and IDH2 mutations in gliomas |journal=N. Engl. J. Med. |volume=360 |issue=8 |pages=765–73 |year=2009 |month=February |pmid=19228619 |pmc=2820383 |doi=10.1056/NEJMoa0808710 |url=}}</ref><ref name=pmid20975057>{{cite journal |author=Houillier C, Wang X, Kaloshi G, ''et al.'' |title=IDH1 or IDH2 mutations predict longer survival and response to temozolomide in low-grade gliomas |journal=Neurology |volume=75 |issue=17 |pages=1560–6 |year=2010 |month=October |pmid=20975057 |doi=10.1212/WNL.0b013e3181f96282 |url=}}</ref>
*[[H3F3A|H3F3A K27M]] in [[Diffuse midline glioma, H3 K27-altered]].
*[[ATRX]] -ve in [[Astrocytoma, IDH-mutant]] or [[Diffuse hemispheric glioma, H3 G34-mutant]].
*[[CD20]] in PCNSL.
*Cytokeratins in Carcinoma brain metastases, Plexus choroid tumours, [[AT/RT]], [[Papillary tumour of the pineal region]], [[Craniopharyngioma]].
*[[EMA]] in [[Meningioma]] and carcinoma brain metastases.
*PrgR in [[Meningioma]] and carcinoma metastases.
*[[Synaptophysin]] in glioneuronal tumours and Pituitary adenoma and embryonal tumours.


===Common neuropathology tumours in a table===
===Common neuropathology tumours in a table===
Line 100: Line 195:
|missed lesion?
|missed lesion?
|nil
|nil
|[http://commons.wikimedia.org/wiki/File:Grey_matter_and_white_matter_-_very_high_mag.jpg very high mag.], [http://commons.wikimedia.org/wiki/File:Grey_matter_and_white_matter_-_high_mag.jpg high mag.]
|[[Image:Grey_matter_and_white_matter_-_very_high_mag.jpg |thumb|center|150px|Normal. (WC)]]
|-
|-
|[[Reactive astrocytes]]
|[[Reactive astrocytes]]
Line 107: Line 202:
|variable
|variable
|missed lesion / close to a lesion; non-specific pathologic process - need more tissue
|missed lesion / close to a lesion; non-specific pathologic process - need more tissue
|nil
|GFAP
|[http://commons.wikimedia.org/wiki/File:Reactive_astrocytes_-_lfb_-_high_mag.jpg high mag.]
|[[Image:Reactive_astrocytes_-_lfb_-_high_mag.jpg|thumb|center|150px|Reactive astrocytes. (WC)]]
|-
|[[Schwannoma]]
|cellular areas (Antoni A), paucicelluar areas (Antoni B), palisading of nuclei (Verocay bodies)
|extra-axial + intradural
|old or young
|need frozen section to Dx, DDx: [[meningioma]]
|S100, SOX10
|[[Image:Schwannoma_-_Antoni_A_and_B_-_very_high_mag.jpg|thumb|center|150px|Schwannoma. (WC)]]
|-
|[[Meningioma]]
|whorls, psammomatous calcs, nuclear inclusions
|extra-axial + intradural
|old or young
|may be diagnosed on smear, DDx: [[schwannoma]], choroid plexus
|EMA, PR, Ki-67
|[[Image:Meningioma_intermed_mag.jpg |thumb|center|150px|Meningioma. (WC)]]
|-
|[[Astrocytoma, IDH-mutant]] (CNS [[WHO]] grade 2 or grade 3)
|glial processes (esp. on smear), nuclear atypia (typical size var. ~3x, irreg. nuc. membrane, hyperchromasia), no Rosenthal fibres in the core of the lesion †, no microvascular proliferation, no necrosis
|often enhancing (suggests high grade), usu. supratentorial, usu. white matter
|usu. old, occ. young
|common
|IDH-1(R132H)+/-, GFAP+
| [[Image:Anaplastic_astrocytoma_-_very_high_mag_-_cropped.jpg | thumb| center| 150px|High-grade astrocytoma. (WC)]]
|-
|-
|[[Astrocytoma]] (grade II or worse)
|[[Glioblastoma]], IDH-wildtype (CNS [[WHO]] grade 4)
|glial processes (esp. on smear), nuclear atypia (size var. ~3x, irreg. nuc. membrane, hyperchromasia), no Rosenthal fibres in the core of the lesion †
|glial processes (esp. on smear), nuclear atypia (typical size var. ~3x, irreg. nuc. membrane, hyperchromasia), no Rosenthal fibres in the core of the lesion †, microvascular proliferation or necrosis
|often enhancing (suggests high grade), usu. supratentorial, usu. white matter
|often enhancing (suggests high grade), usu. supratentorial, usu. white matter
|usu. old, occ. young
|usu. old, occ. young
|very common, esp. glioblastoma
|very common, esp. glioblastoma
|IDH-1+/-, GFAP+
|IDH-1+/-, GFAP+
|[http://commons.wikimedia.org/wiki/File:Anaplastic_astrocytoma_-_high_mag.jpg high mag.], [http://commons.wikimedia.org/wiki/File:Anaplastic_astrocytoma_-_very_high_mag_-_cropped.jpg very high mag.]
| [[Image:Glioblastoma (1).jpg | thumb| center| 150px|Glioblastoma. (WC)]]
|-
|-
|Metastasis
|[[Metastatic brain tumours|Metastasis]]
|sharp interface with brain, often glandular, +/-nucleoli, no glial processes
|sharp interface with brain, often glandular, +/-nucleoli, no glial processes
|often cerebellular, well-circumscribed
|often cerebellular, well-circumscribed
|usu. old
|usu. old
|often suspected to have metastatic disease
|often suspected to have metastatic disease
|TTF-1, CK7, CK20, BRST-2
|[[TTF-1]], CK7, [[CK20]], BRST-2
|[http://commons.wikimedia.org/w/index.php?title=File:Metastatic_adenocarcinoma_-_cerebellum_-_very_low_mag.jpg very low mag.], [http://commons.wikimedia.org/w/index.php?title=File:Metastatic_adenocarcinoma_-_cerebellum_-_high_mag.jpg high mag.]
|[[Image:Metastatic_adenocarcinoma_-_cerebellum_-_very_low_mag.jpg | thumb| center|150px |Metastasis. (WC)]]
|-
|[[Meningioma]]
|whorls, psammomatous calcs, nuclear inclusions
|extra-axial + intradural
|old or young
|may be diagnosed on smear, DDx: choroid plexus, schwannoma
|EMA, PR, Ki-67
|[http://commons.wikimedia.org/wiki/File:Meningioma_intermed_mag.jpg intermed. mag.]
|-
|[[Schwannoma]]
|cellular areas (Antoni A), paucicelluar areas (Antoni B), palisading of nuclei (Verocay bodies)
|extra-axial + intradural
|old or young
|need frozen section to Dx
|S100
|[http://commons.wikimedia.org/wiki/File:Schwannoma_-_Antoni_A_and_B_-_intermed_mag.jpg intermed. mag.],
[http://commons.wikimedia.org/wiki/File:Schwannoma_-_Antoni_A_and_B_-_very_high_mag.jpg very high mag.]
|}
|}
† Rosenthal fibres at the periphery of a lesion are a non-specific finding seen in chronic processes.
† Rosenthal fibres at the periphery of a lesion are a non-specific finding seen in chronic processes.


==Metastatic tumours==
==Brain metastasis==
===General===
{{Main|Brain metastasis}}
*Most common brain tumour in adults.
 
 
===Molecular===
See also:  [[Molecular_pathology_tests#Neuropathology|Molecular Neuropathology]]


===Microscopic===
==Gliomas==
Features:
{{Main|Glioma}}
*Vary by subtype.


Images:
Gliomas, glioneuronal tumours and neuronal tumours are often categorized together.
*[http://commons.wikimedia.org/wiki/File:Metastatic_adenocarcinoma_-_cerebellum_-_very_low_mag.jpg CRC metastasis to cerebellum - very low mag. (WC)].
*[http://commons.wikimedia.org/wiki/File:Metastatic_adenocarcinoma_-_cerebellum_-_high_mag.jpg CRC metastasis to cerebellum - high mag. (WC)].


==Infiltrative astrocytomas==  
===Astrocytic tumours===
{{Main|Astrocytoma}}
{{Main|Astrocytoma}}


===Overview===
* [[Astrocytoma]], IDH-mutant.
*Low-grade (diffuse) astrocytomas (Grade II).
* [[Glioblastoma]], IDH-wildtype.
*Anaplastic astrocytomas (Grade III).
** [[Gliosarcoma]] (a glioblastoma subtype)
*Glioblastoma (Grade IV).


Notes:
*Non-infiltrative gliomas:
**[[Pilocytic astrocytoma]] (WHO Grade I).
**[[Dysembryoplastic neuroepithelial tumour]] (DNT), (WHO Grade I).
===Microscopic===
Features:<ref name=pmid>{{cite journal |author=Rong Y, Durden DL, Van Meir EG, Brat DJ |title='Pseudopalisading' necrosis in glioblastoma: a familiar morphologic feature that links vascular pathology, hypoxia, and angiogenesis |journal=J. Neuropathol. Exp. Neurol. |volume=65 |issue=6 |pages=529–39 |year=2006 |month=June |pmid=16783163 |doi= |url=}}</ref><ref>[http://dictionary.reference.com/browse/palisading http://dictionary.reference.com/browse/palisading]</ref>
Features:<ref name=pmid>{{cite journal |author=Rong Y, Durden DL, Van Meir EG, Brat DJ |title='Pseudopalisading' necrosis in glioblastoma: a familiar morphologic feature that links vascular pathology, hypoxia, and angiogenesis |journal=J. Neuropathol. Exp. Neurol. |volume=65 |issue=6 |pages=529–39 |year=2006 |month=June |pmid=16783163 |doi= |url=}}</ref><ref>[http://dictionary.reference.com/browse/palisading http://dictionary.reference.com/browse/palisading]</ref>
*Glial processes - '''key feature'''.
*Glial processes - '''key feature'''.
Line 181: Line 276:
*[http://path.upmc.edu/cases/case368.html Gemistocytic astrocytoma - several images (upmc.edu)].
*[http://path.upmc.edu/cases/case368.html Gemistocytic astrocytoma - several images (upmc.edu)].


Notes:
Depreceated:
*Glial vs. non-glial tumours:
* Diffuse [[Astrocytoma]]
**Glial: "blends into brain"/gradual transition to non-tumour brain.
* [[Anaplastic astrocytoma]]
**Non-glial: no glial processes.
* [[Gliomatosis cerebri]]
*Rosenthal fibres within the tumour... make it into a [[pilocytic astrocytoma]].
* Spongioblastoma
**Rosenthal fibres may be seen around a (very) slow growing tumour and represent a reactive process.
*Inflammatory cells and macrophages should prompt consideration of an alternate diagnosis (e.g. [[cerebral infarct]], [[multiple sclerosis]]) - esp. if this is a primary lesion.<ref>URL: [http://path.upmc.edu/cases/case79/dx.html http://path.upmc.edu/cases/case79/dx.html]. Accessed on: 2 January 2012.</ref>
 
====Grading====
Nuclear pleomorphism present:
*At least grade II (diffuse astrocytoma).


Mitotic figures present:
===Oligodendroglial tumours===
*At least grade III (anaplastic astrocytoma).
* [[Oligodendroglioma]], IDH-mutant and 1p/19q codeleted.


Microvascular proliferation ''or'' necrosis with pseudopalisading tumour cells:
Depreceated:
*Grade IV (glioblastoma [[AKA]] glioblastoma multiforme).
* Anaplastic oligodendroglioma
* [[Oligoastrocytoma]]  
* Anaplastic oligoastrocytoma


Notes:
===Pediatric-type diffuse high-grade glioma===
*Pseudopalisading tumour cells = high tumour cell density adjacent to regions of necrosis; palisade = a fence of pales forming a defense barrier or fortification.  
{{Main|Pediatric-type diffuse high-grade glioma}}
* [[Astrocytoma#Diffuse_midline_glioma.2C_H3_K27M_mutant|Diffuse midline glioma H3 K27-mutant]]


Images:
===Pediatric-type diffuse low-grade glioma===
*Glioblastoma:
{{Main|Pediatric-type diffuse low-grade glioma}}
**[http://commons.wikimedia.org/wiki/File:Glioblastoma_%281%29.jpg Glioblastoma - pseudopalisading of tumour cells (WC)].
**[http://commons.wikimedia.org/wiki/File:Glioblastoma_-_high_mag.jpg Glioblastoma with fragment of near-normal white matter - high mag. (WC)].
*Anaplastic astrocytoma:
**[http://commons.wikimedia.org/wiki/File:Anaplastic_astrocytoma_-_very_high_mag_-_cropped.jpg Anaplastic astrocytoma - very high mag. (WC)].
**[http://commons.wikimedia.org/wiki/File:Anaplastic_astrocytoma_-_gfap_-_very_high_mag.jpg Anaplastic astrocytoma - GFAP - very high mag. (WC)].
 
=====Table of common gliomas - grading=====
Histomorphologic comparison of common gliomas:
{| class="wikitable"
|'''Entity''' || '''Rosenthal <br>fibres / EGBs''' ||'''Nuclear atypia''' ||'''Mitoses''' || '''Necrosis or MVP''' || '''Infiltrative''' || '''Image'''
|-
|Pilocytic astrocytoma || yes || usu. no || usu. no || usu. no || no || [http://commons.wikimedia.org/wiki/File:Rosenthal_HE_40x.jpg]
|-
|Low-grade astrocytoma || no || yes || no || no || yes || image?
|-
|Anaplastic astrocytoma || no || yes || yes || no || yes || [http://commons.wikimedia.org/wiki/File:Anaplastic_astrocytoma_-_high_mag.jpg]
|-
|Glioblastoma || no || yes || yes || yes || yes || [http://commons.wikimedia.org/wiki/File:Glioblastoma_-_high_mag.jpg]
|}
Notes:
*''MVP'' = microvascular proliferation.
*''EGBs'' = eosinophilic granular bodies.
 
===IHC===
*GFAP - should stain cytoplasm of tumour cells and the perikaryon (nuclear membrane).
*Ki-67 - usu. high >20% of cells.
*p53 - often +ve.
*IDH1 (isocitrate dehydrogenase 1).
**+ve in tumours that arose from low-grade gliomas.<ref name=pmid19228619>{{cite journal |author=Yan H, Parsons DW, Jin G, ''et al.'' |title=IDH1 and IDH2 mutations in gliomas |journal=N. Engl. J. Med. |volume=360 |issue=8 |pages=765–73 |year=2009 |month=February |pmid=19228619 |pmc=2820383 |doi=10.1056/NEJMoa0808710 |url=}}</ref>
***Image: [http://en.wikipedia.org/wiki/File:IDH1_GBM_20x.jpg IDH1 +ve in glioblastoma (WP)].
 
Notes:
*IDH1 and IDH2 mutations - better survival.<ref name=pmid20975057>{{cite journal |author=Houillier C, Wang X, Kaloshi G, ''et al.'' |title=IDH1 or IDH2 mutations predict longer survival and response to temozolomide in low-grade gliomas |journal=Neurology |volume=75 |issue=17 |pages=1560–6 |year=2010 |month=October |pmid=20975057 |doi=10.1212/WNL.0b013e3181f96282 |url=}}</ref>


==Pilocytic astrocytoma==
===General===
*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===
===Circumscribed astrocytic gliomas===
Features:<ref name=Ref_PSNP82>{{Ref PSNP|82}}</ref>
* [[Pilocytic astrocytoma]] (PA)
*Usually well-circumscribed.
** [[Pilomyxoid astrocytoma]] (PMA)
*Cystic ''or'' solid.
* [[Pleomorphic xanthoastrocytoma]] (PXA)
*Do '''not''' smear. (Ref. ?)
* [[Subependymal giant cell astrocytoma]] (SEGA)
* [[Neuropathology_tumours#Astroblastoma|Astroblastoma MN1-altered]].
* [[Neuropathology_tumours#Chordoid glioma of the third ventricl|Chordoid glioma]].


===Microscopic===
====Astroblastoma====
Features:<ref name=Ref_PSNP82-4>{{Ref PSNP|82-4}}</ref>
*No WHO grade yet.<ref>{{Ref WHOCNS|88}}</ref>
*Classically biphasic (though either may be absent):
*Very rare superficial tumor of young age.<ref>{{Cite journal  | last1 = Narayan | first1 = S. | last2 = Kapoor | first2 = A. | last3 = Singhal | first3 = MK. | last4 = Jakhar | first4 = SL. | last5 = Bagri | first5 = PK. | last6 = Rajput | first6 = PS. | last7 = Kumar | first7 = HS. | title = Astroblastoma of cerebrum: A rare case report and review of literature. | journal = J Cancer Res Ther | volume = 11 | issue = 3 | pages = 667 | month =  | year =  | doi = 10.4103/0973-1482.140800 | PMID = 26458709 }}</ref>
*#Fibrillar.
*Large, cystic. Pushing margin towards CNS.
*#Microcystic/loose.
*Vasocentric growth, plump cells with absence of fibrillary pattern.
*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>
*GFAP+ve, Synaptohysin-ve, Olig-2-ve, focally EMA/panCK+ve. MIB-1: 1-18 %.
**Best seen on smear or with GFAP [[IHC]].
*Molecular profile overlaps with classical [[CNS-PNET]].
*Rosenthal fibres - '''key feature'''.
**Gene fusions invoving meningioma gene (MN1)<ref>{{Cite journal  | last1 = Sturm | first1 = D. | last2 = Orr | first2 = BA. | last3 = Toprak | first3 = UH. | last4 = Hovestadt | first4 = V. | last5 = Jones | first5 = DT. | last6 = Capper | first6 = D. | last7 = Sill | first7 = M. | last8 = Buchhalter | first8 = I. | last9 = Northcott | first9 = PA. | title = New Brain Tumor Entities Emerge from Molecular Classification of CNS-PNETs. | journal = Cell | volume = 164 | issue = 5 | pages = 1060-72 | month = Feb | year = 2016 | doi = 10.1016/j.cell.2016.01.015 | PMID = 26919435 }}</ref>
**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>
<gallery>
*Chronic reactive gliosis.
File:Astroblastoma_HE_Specimen.jpg | HE. (WC/jensflorian)
*Subependymoma.
File:Astroblastoma_HE_papillae.jpg | HE. (WC/jensflorian)
*Ganglioma.
File:Astroblastoma.jpg | Astroblastoma (AFIP)
*Alexander's disease (rare leukodystrophy).
</gallery>


DDx of pilocystic astrocytoma (brief):
====Chordoid glioma of the third ventricle====
*Piloid gliosis.
* WHO grade II.
*Oligodendroglioma.
* Slowly growing, non-invasive, in adults.
*Glioblastoma (uncommon - but important).
* Clusters of epithelioid cells in mucinous stroma.
* Lymphocytic infiltrates, adjacent Rosenthal fibers.
* Fibrosis may be present.
* Few mitoses.
* [[GFAP]]+ve,  MIB-1 1-3%.
* [[TTF-1]]+ve.
* CD34+ve.
* [[IDH-1]]-ve, [[p53]]-ve.
* PRKCA D463H mutations.<ref>{{Cite journal  | last1 = Goode | first1 = B. | last2 = Mondal | first2 = G. | last3 = Hyun | first3 = M. | last4 = Ruiz | first4 = DG. | last5 = Lin | first5 = YH. | last6 = Van Ziffle | first6 = J. | last7 = Joseph | first7 = NM. | last8 = Onodera | first8 = C. | last9 = Talevich | first9 = E. | title = A recurrent kinase domain mutation in PRKCA defines chordoid glioma of the third ventricle. | journal = Nat Commun | volume = 9 | issue = 1 | pages = 810 | month = 02 | year = 2018 | doi = 10.1038/s41467-018-02826-8 | PMID = 29476136 }}</ref>


Images:
<gallery>
*Smears:
File:NP op 20201028 009.jpg | Chordoid Glioma. (WC/jensflorian)
**[http://commons.wikimedia.org/wiki/File:Pilocytic_astrocytoma_-_smear_-_very_high_mag.jpg Bipolar cells with hair-like processes - smear - very high mag. (WC)].
</gallery>
**[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===
===Ependymal tumours===
*''WHO Grade I'' by definition.
* [[Subependymoma]]
* [[Myxopapillary Ependymoma]]
* [[Ependymoma]]
* Anaplastic ependymoma


==Pleomorphic xanthoastrocytoma==
==Choroid plexus tumours==
*Abbreviated ''PXA''.
* [[Choroid plexus papilloma]]
===General===
* Atypical choroid plexus papilloma
Features:
* [[Choroid plexus carcinoma]]
*Classically in the temporal lobe in children and young adults.
*Associated with seizures.


===Microscopic===
==Other neuroepithelial tumours==
Features:<ref name=Ref_PBoD8_1333>{{Ref PBoD8|1333}}</ref>
* [[Neuropathology_tumours#Cribiform_neuroepithelial_tumour|Cribifiorm neuroepithelial tumour]].
*Marked nuclear atypia.
*Inflammation (chronic).


Notes:
*No mitoses.
*No necrosis.


Images:
===Cribiform neuroepithelial tumour===
*[http://path.upmc.edu/cases/case499.html Pleomorphic xanthoastrocytoma - several images (upmc.edu)].
AKA: '''CRINET'''.
*[http://path.upmc.edu/cases/case511.html Pleomorphic xanthoastrocytoma - another case - several images (upmc.edu)].
*Not listed in the current WHO classification.
*[http://path.upmc.edu/cases/case578.html Pleomorphic xanthoastrocytoma - case 3 - several images (upmc.edu)].
*First description in 2009.<ref>{{Cite journal  | last1 = Hasselblatt | first1 = M. | last2 = Oyen | first2 = F. | last3 = Gesk | first3 = S. | last4 = Kordes | first4 = U. | last5 = Wrede | first5 = B. | last6 = Bergmann | first6 = M. | last7 = Schmid | first7 = H. | last8 = Frühwald | first8 = MC. | last9 = Schneppenheim | first9 = R. | title = Cribriform neuroepithelial tumor (CRINET): a nonrhabdoid ventricular tumor with INI1 loss and relatively favorable prognosis. | journal = J Neuropathol Exp Neurol | volume = 68 | issue = 12 | pages = 1249-55 | month = Dec | year = 2009 | doi = 10.1097/NEN.0b013e3181c06a51 | PMID = 19915490 }}</ref>
*[http://path.upmc.edu/cases/case579.html Pleomorphic xanthoastrocytoma - case 4 - several image (upmc.edu)].
*Around ventricles.<ref>{{Cite journal  | last1 = Arnold | first1 = MA. | last2 = Stallings-Archer | first2 = K. | last3 = Marlin | first3 = E. | last4 = Grondin | first4 = R. | last5 = Olshefski | first5 = R. | last6 = Biegel | first6 = JA. | last7 = Pierson | first7 = CR. | title = Cribriform neuroepithelial tumor arising in the lateral ventricle. | journal = Pediatr Dev Pathol | volume = 16 | issue = 4 | pages = 301-7 | month =  | year =  | doi = 10.2350/12-12-1287-CR.1 | PMID = 23495723 }}</ref>
*Young children.<ref>{{Cite journal  | last1 = Park | first1 = JY. | last2 = Kim | first2 = E. | last3 = Kim | first3 = DW. | last4 = Chang | first4 = HW. | last5 = Kim | first5 = SP. | title = Cribriform neuroepithelial tumor in the third ventricle: a case report and literature review. | journal = Neuropathology | volume = 32 | issue = 5 | pages = 570-6 | month = Oct | year = 2012 | doi = 10.1111/j.1440-1789.2011.01293.x | PMID = 22239490 }}</ref>
*Small undifferentiated cells arranged in cribriform strands and trabeculae of varying thickness.
*MAP2+ve, Synaptophysin+ve, CK+/-ve. MIB-1: 30%.
*INI-1 loss, but no rhabdoid features and good prognosis.  
*Stable genomic profile.<ref>{{Cite journal  | last1 = Gessi | first1 = M. | last2 = Japp | first2 = AS. | last3 = Dreschmann | first3 = V. | last4 = Zur Mühlen | first4 = A. | last5 = Goschzik | first5 = T. | last6 = Dörner | first6 = E. | last7 = Pietsch | first7 = T. | title = High-Resolution Genomic Analysis of Cribriform Neuroepithelial Tumors of the Central Nervous System. | journal = J Neuropathol Exp Neurol | volume = 74 | issue = 10 | pages = 970-4 | month = Oct | year = 2015 | doi = 10.1097/NEN.0000000000000239 | PMID = 26352987 }}</ref>


===IHC===
==Neuronal and mixed neuronal/glial tumours==
*GFAP +ve.
* [[Desmoplastic infantile astrocytoma]] / ganglioglioma (DIA/DIG)
*CD68 +ve.
* [[Dysembryoplastic neuroepithelial tumour]]
* [[Central Neurocytoma]] / Extraventricular [[neurocytoma]]
* Cerebellar liponeurocytoma
* [[Papillary glioneuronal tumour]] (PGNT)
* [[Rosette-forming glioneuronal tumour of the fourth ventricle]] (RGNT)
* Gangliocytoma / Ganglioglioma
* Dysplastic ganglioglioma of the cerebellum ([[Lhermitte-Duclos disease]])
* [[Paraganglioma]]


==Dysembryoplastic neuroepithelial tumour==
===Desmoplastic infantile astrocytoma / Desmoplastic infantile ganglioglioma===
*Abbreviated ''DNT''.
* Abbreviated ''DIA'' or ''DIG''.
* ICD-O code: 9412/1
* Large, superficial, cystic tumor of the infancy.
* Biologic course corresponds to WHO grade I.
* Very rare, included in the WHO since 1993.
* Prominent desmoplastic stroma.
* Astrocytic cells within stroma.
**GFAP+.
**MIB-1 usu. 1%.
* Frequent BRAF V600E or V600D mutations.<ref>{{Cite journal  | last1 = Wang | first1 = AC. | last2 = Jones | first2 = DTW. | last3 = Abecassis | first3 = IJ. | last4 = Cole | first4 = BL. | last5 = Leary | first5 = SES. | last6 = Lockwood | first6 = CM. | last7 = Chavez | first7 = L. | last8 = Capper | first8 = D. | last9 = Korshunov | first9 = A. | title = Desmoplastic Infantile Ganglioglioma/Astrocytoma (DIG/DIA) are Distinct Entities with Frequent BRAFV600 Mutations. | journal = Mol Cancer Res | volume =  | issue =  | pages =  | month = Jul | year = 2018 | doi = 10.1158/1541-7786.MCR-17-0507 | PMID = 30006355 }}</ref>
*Single case with BRAF indel or BRAF fusion.
<gallery>
File:DIG-histology.jpg | Histopathology of DIG (HE stain)
File:DIG-histology2.jpg | Prominent ganglioid cells in DIG (HE stain)
</gallery>


===General===
===Cerebellar liponeurocytoma===
*Common tumour cause of drug resistant epilepsy.<ref name=pmid15881751>{{Cite journal  | last1 = Cataltepe | first1 = O. | last2 = Turanli | first2 = G. | last3 = Yalnizoglu | first3 = D. | last4 = Topçu | first4 = M. | last5 = Akalan | first5 = N. | title = Surgical management of temporal lobe tumor-related epilepsy in children. | journal = J Neurosurg | volume = 102 | issue = 3 Suppl | pages = 280-7 | month = Apr | year = 2005 | doi = 10.3171/ped.2005.102.3.0280 | PMID = 15881751 }}</ref>
* Previously called ''lipomatous medulloblastoma'' (name changed in WHO 2000).
*Paediatric population.
* Mean age: 50 years.
* As the name states: A tumour of the cerebellum.
** But cases outside cerebellum reported that would qualify.<ref>{{Cite journal  | last1 = Gupta | first1 = K. | last2 = Salunke | first2 = P. | last3 = Kalra | first3 = I. | last4 = Vasishta | first4 = RK. | title = Central liponeurocytoma: case report and review of literature. | journal = Clin Neuropathol | volume = 30 | issue = 2 | pages = 80-5 | month =  | year =  | doi =  | PMID = 21329617 }}</ref>
* WHO grade II <ref>{{Cite journal  | last1 = Nishimoto | first1 = T. | last2 = Kaya | first2 = B. | title = Cerebellar liponeurocytoma. | journal = Arch Pathol Lab Med | volume = 136 | issue = 8 | pages = 965-9 | month = Aug | year = 2012 | doi = 10.5858/arpa.2011-0337-RS | PMID = 22849747 }}</ref> (upgraded from WHO grade I in 2007)<ref>{{Cite journal  | last1 = Brat | first1 = DJ. | last2 = Parisi | first2 = JE. | last3 = Kleinschmidt-DeMasters | first3 = BK. | last4 = Yachnis | first4 = AT. | last5 = Montine | first5 = TJ. | last6 = Boyer | first6 = PJ. | last7 = Powell | first7 = SZ. | last8 = Prayson | first8 = RA. | last9 = McLendon | first9 = RE. | title = Surgical neuropathology update: a review of changes introduced by the WHO classification of tumours of the central nervous system, 4th edition. | journal = Arch Pathol Lab Med | volume = 132 | issue = 6 | pages = 993-1007 | month = Jun | year = 2008 | doi = 10.1043/1543-2165(2008)132[993:SNUARO]2.0.CO;2 | PMID = 18517285 }}</ref>
*ICD-O code: 9506/1


===Gross/radiology===
====Histo====
*Temporal lobe.
* Advanced neuronal and lipomatous differentiation.
*Variable architecture:<ref name=pmid18071981/> cystic, solitary nodular, multinodular.  
* Neurocytes: round to oval nuclei with clear cytoplasm.
* Quite cellular.
* Mitoses almost absent.  


===Microscopic===
====IHC====
Features:<ref name=pmid18071981>{{Cite journal  | last1 = O'Brien | first1 = DF. | last2 = Farrell | first2 = M. | last3 = Delanty | first3 = N. | last4 = Traunecker | first4 = H. | last5 = Perrin | first5 = R. | last6 = Smyth | first6 = MD. | last7 = Park | first7 = TS. | title = The Children's Cancer and Leukaemia Group guidelines for the diagnosis and management of dysembryoplastic neuroepithelial tumours. | journal = Br J Neurosurg | volume = 21 | issue = 6 | pages = 539-49 | month = Dec | year = 2007 | doi = 10.1080/02688690701594817 | PMID = 18071981 }}</ref>
* [[GFAP]] +/-ve (focal).  
*Cells similar to oligodendrocytes:
* [[MAP2]] +ve.
**Large central nuclei with indentations.
* Synaptophysin +ve.
**Multiple small nucleoli (common).
* NeuN +ve.
**Clear cytoplasm.
* MIB-1: usu 1-3%.


DDx:
====Molecular====
*[[Oligodendroglioma]].
* Distinct methylation profile.
**These have rounder, smaller nuclei with occasional nucleoli.<ref name=pmid18071981/>
* Recurent losses on 2p and Chr. 14.<ref>{{Cite journal  | last1 = Capper | first1 = D. | last2 = Stichel | first2 = D. | last3 = Sahm | first3 = F. | last4 = Jones | first4 = DTW. | last5 = Schrimpf | first5 = D. | last6 = Sill | first6 = M. | last7 = Schmid | first7 = S. | last8 = Hovestadt | first8 = V. | last9 = Reuss | first9 = DE. | title = Practical implementation of DNA methylation and copy-number-based CNS tumor diagnostics: the Heidelberg experience. | journal = Acta Neuropathol | volume = | issue =  | pages =  | month = Jul | year = 2018 | doi = 10.1007/s00401-018-1879-y | PMID = 29967940 }}</ref>


Images:
<gallery>
*[http://commons.wikimedia.org/wiki/File:DNET_HE.jpg DNT (WC)].
File:Cerebellar liponeurocytoma.jpg | Liponeurocytoma, HE (WC/Marvin101).
*[http://path.upmc.edu/cases/case106.html DNT - several images (upmc.edu)].
File:Liponeurocytoma Synaptophysin.jpg | Liponeurocytoma, Synapto (WC/Marvin101).
File:Cerebellar Liponeurocytoma HE.jpg | Liponeurocytoma, HE (WC/jensflorian).
File:Cerebellar Liponeurocytoma Synaptophysin.jpg | Liponeurocytoma, Synapto (WC/jensflorian).
</gallery>


==Subependymal giant cell astrocytoma==
====DDx====
*Abbreviated ''SEGA''.
* [[Medulloblastoma]]
* [[Neurocytoma]]


===General===
===Gangliocytoma===
*Associated with [[tuberous sclerosis complex]] (TSC).<ref name=pmid21455842>{{Cite journal  | last1 = Grajkowska | first1 = W. | last2 = Kotulska | first2 = K. | last3 = Jurkiewicz | first3 = E. | last4 = Roszkowski | first4 = M. | last5 = Daszkiewicz | first5 = P. | last6 = Jóźwiak | first6 = S. | last7 = Matyja | first7 = E. | title = Subependymal giant cell astrocytomas with atypical histological features mimicking malignant gliomas. | journal = Folia Neuropathol | volume = 49 | issue = 1 | pages = 39-46 | month =  | year = 2011 | doi =  | PMID = 21455842 }}</ref>
* Grade I WHO neuronal tumour.
*WHO Grade I.
** ICD-O code: 9492/0
* Groups of irregular large neurons.
* Non-neoplastic, reticulin-rich glial stroma.


===Gross/radiology===
===Ganglioglioma===
*Well-demarcated.
:'''Not''' to be confused with ''[[ganglioneuroma]]''.
====General====
*Gangliolioma: Grade I WHO mixed neuronal-glial tumour (ICD-O code: 9505/1).
*Anaplastic ganglioglioma: Grade III (ICD-O: 9505/3)
*Rare (approx. 0.5% of all CNS tumors).
*Usu. temporal lobe.
*Predominantly children (mean age: 9 years).
*Recognized as a cause of [[epilepsy]].<ref name=pmid12125968>{{Cite journal  | last1 = Im | first1 = SH. | last2 = Chung | first2 = CK. | last3 = Cho | first3 = BK. | last4 = Lee | first4 = SK. | title = Supratentorial ganglioglioma and epilepsy: postoperative seizure outcome. | journal = J Neurooncol | volume = 57 | issue = 1 | pages = 59-66 | month = Mar | year = 2002 | doi =  | PMID = 12125968 }}</ref>
*Favourable prognosis (survival rates up to 97%)
**Insufficient data für anaplastic ganglioglioma.


===Microscopic===
====Macroscopic====
Features:<ref name=upmc_case179/><ref name=pmid9595853>{{Cite journal  | last1 = Taraszewska | first1 = A. | last2 = Kroh | first2 = H. | last3 = Majchrowski | first3 = A. | title = Subependymal giant cell astrocytoma: clinical, histologic and immunohistochemical characteristic of 3 cases. | journal = Folia Neuropathol | volume = 35 | issue = 3 | pages = 181-6 | month =  | year = 1997 | doi =  | PMID = 9595853 }}</ref>
*Circumscribed lesion.
*Giant cells with nuclear atypia ("bizarre cells").
*Usu. contrast enhancing.
**Vesicular nuclei.
*Solid, but intracortical cysts may be present.
**[[Nuclear pseudoinclusions]].<ref name=upmc179>URL: [http://path.upmc.edu/cases/case179/micro.html http://path.upmc.edu/cases/case179/micro.html]. Accessed on: 8 January 2012.</ref>
*Little mass effect.
*Glassy eosinophilic cytoplasm.
*Abundant [[mast cell]]s.<ref name=upmc179>URL: [http://path.upmc.edu/cases/case179/micro.html http://path.upmc.edu/cases/case179/micro.html]. Accessed on: 8 January 2012.</ref>


Images:
*[http://path.upmc.edu/cases/case179/micro.html SEGA (upmc.edu)].<ref name=upmc_case179>URL: [http://path.upmc.edu/cases/case179.html http://path.upmc.edu/cases/case179.html]. Accessed on: 29 July 2011.</ref>
*[http://path.upmc.edu/cases/case500.html SEGA - another case (upmc.edu)].


===IHC===
====Microscopic====
Features:<ref name=pmid9595853/>
*GFAP +ve. (???)
*Vimentin +ve. (???)
*S100 +ve. (???)
 
==Pilomyxoid astrocytoma==
===General===
Features:<ref name=Ref_PSNP86>{{Ref PSNP|86}}</ref>
*A variant of ''pilocytic astrocytoma''.
**Some have suggested it is a unique entity.<ref name=pmid16048293>{{cite journal |author=Komotar RJ, Mocco J, Jones JE, ''et al.'' |title=Pilomyxoid astrocytoma: diagnosis, prognosis, and management |journal=Neurosurg Focus |volume=18 |issue=6A |pages=E7 |year=2005 |month=June |pmid=16048293 |doi= |url=}}</ref>
*Childhood or adolescence.
 
===Gross===
Features:<ref name=Ref_PSNP86>{{Ref PSNP|86}}</ref>
*Classically - hypothalamic location/suprasellar location; may involve the sella turcica.<ref name=pmid19766001>{{cite journal |author=Alimohamadi M, Bidabadi MS, Ayan Z, Ketabchi E, Amirjamshidi A |title=Pilomyxoid astrocytoma with involvement of the sella turcica in an adolescent |journal=J Clin Neurosci |volume=16 |issue=12 |pages=1648–9 |year=2009 |month=December |pmid=19766001 |doi=10.1016/j.jocn.2009.01.035 |url=}}</ref>
*Solid.
*Well-circumscribed.
 
===Microscopic===
Features:<ref name=Ref_PSNP86>{{Ref PSNP|86}}</ref>
*Consists of small round/ovoid bland cells in a [[myxoid stroma]].
*Hair-like fibres ~ 1 micrometer.
**Often difficult to appreciate on standard (H&E) histologic sections.
*Usually angiocentric (surround blood vessel) - '''key feature'''.
 
Notes:<ref name=Ref_PSNP86>{{Ref PSNP|86}}</ref>
*Rosenthal fibres are absent - '''key negative'''.
*Monophasic (unlike classical pilocytic astrocytomas) - '''key negative'''.
*May rarely have eosinophilic granular bodies.
 
===Grading===
*''WHO Grade II'' by definition.<ref name=Ref_PSNP86>{{Ref PSNP|86}}</ref>
 
==Atypical teratoid/rhabdoid tumour==
:See also: ''[[Extrarenal malignant rhabdoid tumour]]''.
*Commonly abbreviated ''AT/RT''.
*May be written ''atypical teratoid rhabdoid tumour'', i.e. without the forward slash, or ''atypical teratoid-rhabdoid tumour'' (AT-RT).
 
===General===
*Usually supratentorial, occasionally in posterior fossa, case reports of spinal cord.
 
===Microscopic===
Features:
Features:
*Cellular.
*Dysplastic neurons.
*Small round cells usu. with a prominent nucleolus.
**Out of regular architecture / abnormal location.
*Rhabdoid cells.
**Cytomegaly
**Cells with eosinophilic granular cytoplasm + eccentric nucleus.
**Clustering
*Mitoses.
**Binucleated (very occassionally).
*+/-[[Necrosis]] (common).
*Atypical glia.
*Eosinophilic granular bodies.
*Calcification.
*Prominent capillary network.
*Lymphocytic cuffing.
*May contain some reticulin.
*Glial component may resemble:
**Fibrillary astrocytoma.
**Oligodendroglioma.
**Pilocytic astrocytoma.


DDx:
Anaplastic ganglioglioma:
*[[Primitive neuroectodermal tumour]] (PNET).
*Brisk mitotic activity
*[[Medulloblastoma]].
*Necrosis
*[[Diffuse astrocytoma]].
*[[Choroid plexus carcinoma]].
*[[Embryonal carcinoma]].


Images:
====IHC====
*[http://commons.wikimedia.org/wiki/File:Rhabdoidtumourcell.jpg Rhabdoid tumour cell (WC)].
*Neurons:
*[http://commons.wikimedia.org/wiki/File:ATRT-HE-Overview.jpg AT/RT (WC)].
**[[MAP2]] +ve
*[http://commons.wikimedia.org/wiki/File:ATRT-INI1.jpg AT/RT -ve for INI1 (WC)].
**Synaptophysin +ve
*[http://path.upmc.edu/cases/case99/micro.html AR/RT (upmc.edu)].
** Neurofilament +ve
*Glia:
**CD34+/-ve
*BRAF V600E +ve (approx. 25%, mainly ganglion cells).


===IHC===
====Molecular====
*BAF-47 -ve ([[AKA]] ''INI1'', [[AKA]] ''SMARCB1'' - the HGNC symbol<ref name=omim601607>{{OMIM|601607}}</ref>) - virtually diagnostic.
*BRAF V600E-mutated(approx. 25%).
**Endothelial cells +ve control.
*IDH1/2 wt.
*S-100 +ve.
*No 1p/19q codeletion.
**Few other brain tumours express it.
*Usu. Chr. 7 gain.  
*Vimentin +ve (perinuclear condensation).
*CDKN2A deletions in anaplastic ganglioglioma.  


Others:
====DDx:====
*GFAP +ve (focal - in tumour cells).
*[[DNT]].
*EMA +ve (patchy cytoplasmic).
*[[Oligodendroglioma]].
*Smooth muscle actin +ve.
*Trapped cortical neurons in diffuse astrocytoma.
*Papillary glioneuronal tumor.
*Dysembryoplastic neuroepithelial tumor.


==Oligodendroglioma==
====Images====
===General===
<gallery>
*Do ''not'' arise from oligodendrocytes.
File:Ganglioglioma lymphocytic cuffing PAS.jpg | Lymphocytic cuffing in ganglioglioma (WC/jensflorian)
**Arise from ''glial precursor cells''.
File:Ganglioglioma calcification.jpg | Calcification in ganglioglioma (WC/jensflorian)
File:Ganglioglioma Cd34 x200.jpg | CD34 immunostain in ganglioglioma (WC/jensflorian)
File:Anaplastic ganglioglioma HE.jpg | Pleomorphic ganglion cells in ganglioglioma (WC/jensflorian)
</gallery>
*[http://path.upmc.edu/cases/case142.html Ganglioglioma - case 1 (upmc.edu)].
*[http://path.upmc.edu/cases/case282.html Ganglioglioma - case 2 (upmc.edu)].


Usual location:
===Lhermitte-Duclos disease===
*Fourth ventricle.
*Abbreviated ''LDD''.
*Intramedullary spinal cord.
*[[AKA]] ''dysplastic cerebellar gangliocytoma''.<ref name=pmid20060133>{{Cite journal  | last1 = Yağci-Küpeli | first1 = B. | last2 = Oguz | first2 = KK. | last3 = Bilen | first3 = MA. | last4 = Yalçin | first4 = B. | last5 = Akalan | first5 = N. | last6 = Büyükpamukçu | first6 = M. | title = An unusual cause of posterior fossa mass: Lhermitte-Duclos disease. | journal = J Neurol Sci | volume = 290 | issue = 1-2 | pages = 138-41 | month = Mar | year = 2010 | doi = 10.1016/j.jns.2009.12.010 | PMID = 20060133 }}</ref>
 
*[[AKA]] ''dysplastic gangliocytoma of the cerebellum''.
Prognosis by flavours (average survival):<ref name=Ref_PSNP98>{{Ref PSNP|98}}</ref>
{{Main|Lhermitte-Duclos disease}}
*WHO grade II: 10-15 years.
<gallery>
*WHO grade III: 3-5 years.
File:Dysplastic_gangliocytoma_lhermitte_duclos.jpg | Dysplastic gangliocytoma (low mag).
 
</gallery>
===Microscopic===
Features:
*Highly cellular lesion composed of:
**Cells resembling ''fried eggs'' (oligodendrocytes) with:
***Round nucleus - '''key feature'''.
***Distinct cell borders.
***Moderate-to-marked nuclear atypia.
***Clear cytoplasm - useful feature (if present).
****Some oligodendrogliomas have eosinophilic cytoplasm with focal perinuclear clearing.
**Acutely branched capillary sized vessels - "chicken-wire" like appearance.
***Abundant, delicate appearing; may vaguely resemble a paraganglioma at low power.
*Calcifications - important feature.<ref>URL: [http://www.emedicine.com/radio/topic481.htm http://www.emedicine.com/radio/topic481.htm].</ref>
 
DDx:
*[[Neurocytoma]] also have perinuclear clearing and well-defined cellular borders.
**Pineocytomatous/neurocytic rosettes = (irregular) rosette with a large meshwork of fibers (neuropil) at the centre.


Notes:
===Papillary glioneuronal tumour===
*Few neural tumours have round nuclei - DDx:
* Abbreviated ''PGNT''.
**[[Oligodendroglioma]].
* A benign, supratentorial tumor of childhood.
**[[Lymphoma]].
** Biologic course corresponds to WHO grade I.
**Clear cell variant of [[ependymoma]].
** Before WHO 2000, considered a [[Ganglioglioma]] variant.
**[[Germ cell tumour]] (germinoma/dysgerminoma/seminoma).
*Prominent pseudopapillary architecture.
 
*Neurocytes to medium-sized ganglion cells.
Images:
*GFAP+ core, GFAP- layer
*[http://commons.wikimedia.org/wiki/File:Oligodendroglioma1_high_mag.jpg Oligodendroglioma high mag. (WC)].
*Rosenthal fibers, Eosinophilic Granular bodies and lymphocytic cuffing may be present.
*[http://commons.wikimedia.org/wiki/File:Oligodendroglioma1_low_mag.jpg Oligodendroglioma low mag. (WC)].
<gallery>
File:PGNT_HE_stain.jpg | PGNT (HE) (WC/jensflorian)
</gallery>


====Histologic grading====
===Rosette-forming glioneuronal tumour of the fourth ventricle===
Come in two flavours:
* Abbreviated ''RGNT''.
# WHO grade II.
* Provisional ICD-O code: 9509/1
#*This is most oligodendrogliomas.
* A rare benign infratentorial tumour of the midline of children and adults.
# WHO grade III.
* Biologic course corresponds to WHO grade I.
#*Features for calling high grade:<ref name=Ref_PSNP98>{{Ref PSNP|98}}</ref>
* Glial component corresponds to [[pilocytic astrocytoma]].
#**Endothelial hypertrophy.
* Neurocytic rosettes.
#***Plump/large endothelial cells.
* Eosinopil fibrillary cores / pseudorosettes.
#**Necrosis.
* GFAP+ in fibrillary areas, Syn+ in rosettes.
#**High mitotic rate (6 mitoses/10 HPF for whatever "HPF" means, see [[HPFitis]]).
* Neurocytic cells: MAP2+
* MIB-1 usu. below 3%.
<gallery>
File:Histology RGNT HE.jpg | RGNT, HE stain (WC/jensflorian).
File:RGNT HE 2.jpg | RGNT, higher magnification (WC/jensflorian).
</gallery>


===IHC===
===Polymorphous low-grade tumor of the young (PLNTY)===
Features:
* [[Pediatric-type diffuse low-grade glioma#Diffuse low-grade glioma, MAPK pathway-altered|Polymorphous low-grade tumor of the young (PLNTY)]]
*MAP-2 +ve.<reF name=pmid12025943>{{cite journal |author=Suzuki SO, Kitai R, Llena J, Lee SC, Goldman JE, Shafit-Zagardo B |title=MAP-2e, a novel MAP-2 isoform, is expressed in gliomas and delineates tumor architecture and patterns of infiltration |journal=J. Neuropathol. Exp. Neurol. |volume=61 |issue=5 |pages=403–12 |year=2002 |month=May |pmid=12025943 |doi= |url=}}</ref>
*GFAP -ve.
**Some subtypes +ve - should not be used to distinguish.<ref name=Ref_PSNP>{{Ref PSNP|98}}</ref>
*EMA +ve.
*IDH-1 -ve. (???).
*p53 -ve.
**Useful for differentiating ''astrocytoma'' vs. ''oligodendroglioma''.
*Ki-67.


===Molecular pathology===
==Pineal tumours==
Losses of 1p and 19q both helps with diagnosis and is prognostic:<ref name=pmid18565359>{{cite journal |author=Fontaine D, Vandenbos F, Lebrun C, Paquis V, Frenay M |title=[Diagnostic and prognostic values of 1p and 19q deletions in adult gliomas: critical review of the literature and implications in daily clinical practice] |language=French |journal=Rev. Neurol. (Paris) |volume=164 |issue=6-7 |pages=595–604 |year=2008 |pmid=18565359 |doi=10.1016/j.neurol.2008.04.002 |url=}}</ref>
{{Main|Pineal gland}}
*Greater chemosensitivity
*Better prognosis.


==Oligoastrocytoma==
* [[Pineocytoma]]
===General===
* [[Pineal parenchymal tumour of intermediate differentiation]]
*Mixed tumour.
* [[Pineoblastoma]]
* [[Papillary tumour of the pineal region]]


===Microscopic===
==Embryonal tumours==
Features:
* [[Atypical teratoid/rhabdoid tumour]] (AT/RT) or (AT-RT)
*Astrocytoma-like and oligodendroglioma-like:
* [[Medulloblastoma]]
*#Oligodendroglioma-like cells = round nucleus, peri-nuclear clearing.
* [[Primitive neuroectodermal tumour]] (PNET)
*#Astrocytoma-like cells = non-ovoid/elongated nucleus.
* [[Embryonal tumour with abundant neuropil and true rosettes]] (ETANTR)


DDx:
DDx:
*Anaplastic astrocytoma.
* [[Ewing sarcoma]]
*Oligodendroglioma. (???)
* [[Sarcoma with CIC-rearrangement]]
 
===IHC===
*Oligodendroglioma-like cells: MAP-2 +ve (cytoplasm).
*Astrocytoma-like cells: GFAP +ve (cytoplasm, nuclear membrane).
 
Others:
*Ki-67 ~10%. (???)
*p53 - focally +ve. (???)
*IDH-1 -ve. (???)
 
==Meningioma==
{{Main|Meningioma}}
===General===
*Very common.
*May be part of a syndrome.
 
===Microscopic===
Features (memory device ''WCN''):
*Whorled appearance - '''key feature'''.
*Calcification, psammomatous.
*[[Nuclear pseudoinclusions]] - focal nuclear clearing with a sharp interface to unremarkable chromatin.
 
Grading: see ''[[meningioma]]''.


==Peripheral nerve sheath tumours==
==Peripheral nerve sheath tumours==
{{Main|Peripheral nerve sheath tumours}}
{{Main|Peripheral nerve sheath tumours}}
A classification:<ref name=pmid17893219>{{cite journal |author=Wippold FJ, Lubner M, Perrin RJ, Lämmle M, Perry A |title=Neuropathology for the neuroradiologist: Antoni A and Antoni B tissue patterns |journal=AJNR Am J Neuroradiol |volume=28 |issue=9 |pages=1633–8 |year=2007 |month=October |pmid=17893219 |doi=10.3174/ajnr.A0682 |url=http://www.ajnr.org/cgi/reprint/28/9/1633}}</ref>
A classification:<ref name=pmid17893219>{{cite journal |author=Wippold FJ, Lubner M, Perrin RJ, Lämmle M, Perry A |title=Neuropathology for the neuroradiologist: Antoni A and Antoni B tissue patterns |journal=AJNR Am J Neuroradiol |volume=28 |issue=9 |pages=1633–8 |year=2007 |month=October |pmid=17893219 |doi=10.3174/ajnr.A0682 |url=http://www.ajnr.org/cgi/reprint/28/9/1633}}</ref>
*Benign:
'''Benign:'''
**[[Schwannoma]].
*[[Schwannoma]].
**[[Neurofibroma]].
*[[Neurofibroma]].
**[[Perineurioma]].
*[[Perineurioma]].
*Ganglioneuroma.
**[[Traumatic neuroma]].
**[[Traumatic neuroma]].
*Malignant:
'''Malignant:'''
**[[Malignant peripheral nerve sheath tumour]] (MPNST).
*[[Malignant peripheral nerve sheath tumour]] (MPNST).
 
==Schwannoma==
 
{{Main|Schwannoma}}
===General===
*Tumour of tissue surrounding a nerve.
**Axons adjacent to the tumour are normal... but may be compressed.
 
===Microscopic===
Features:<ref name=pmid17893219>{{cite journal |author=Wippold FJ, Lubner M, Perrin RJ, Lämmle M, Perry A |title=Neuropathology for the neuroradiologist: Antoni A and Antoni B tissue patterns |journal=AJNR Am J Neuroradiol |volume=28 |issue=9 |pages=1633–8 |year=2007 |month=October |pmid=17893219 |doi=10.3174/ajnr.A0682 |url=http://www.ajnr.org/cgi/reprint/28/9/1633}}</ref>
*Antoni A:
**Cellular.
**'Fibrillary, polar, elongated'.
*Antoni B:
**Pauci-cellular.
**Loose microcystic tissue.
*Verocay bodies - paucinuclear area surrounded by palisaded nuclei.
*In the GI tract: classically have a ''peripheral lymphoid cuff''.<ref name=pmid15728600>{{cite journal |author=Levy AD, Quiles AM, Miettinen M, Sobin LH |title=Gastrointestinal schwannomas: CT features with clinicopathologic correlation |journal=AJR Am J Roentgenol |volume=184 |issue=3 |pages=797–802 |year=2005 |month=March |pmid=15728600 |doi= |url=http://www.ajronline.org/cgi/content/full/184/3/797}}</ref>
 
Images:
*[http://www.pathguy.com/~lulo/lulo0003.htm Antoni A (pathguy.com)].
*[http://www.ajnr.org/cgi/content/full/28/9/1633/F8 Antoni A & Antoni B side-by-side (ajnr.org)].
 
Notes:
*Several subtypes exist.
 
==Neurofibroma==
{{Main|Peripheral nerve sheath tumours#Neurofibroma}}
===General===
*May be a part of [[neurofibromatosis]] 1.
*Composed of Schwann cells, axons, fibrous material.<ref name=pmid17893219/>
 
===Microscopic===
Features:
*Spindle cells lesion.
**See ''[[Neurofibroma]]'' article for details.
 
Image:
*[http://commons.wikimedia.org/wiki/File:Neurofibroma_(1).jpg Neurofibroma - low mag. (WC)].
*[http://commons.wikimedia.org/wiki/File:Neurofibroma_(2).jpg Neurofibroma - high mag. (WC)].
*[http://commons.wikimedia.org/wiki/File:Neurofibroma_(3).jpg Neurofibroma - high mag. (WC)].


==Ganglioneuroma==
===Ganglioneuroma===
===General===
:'''Not''' to be confused with ''[[ganglioglioma]]''.
*[[AKA]] ganglioma.<ref>URL: [http://medical-dictionary.thefreedictionary.com/ganglioma http://medical-dictionary.thefreedictionary.com/ganglioma]. Accessed on: 8 November 2010.</ref>
*[[AKA]] ganglioma.<ref>URL: [http://medical-dictionary.thefreedictionary.com/ganglioma http://medical-dictionary.thefreedictionary.com/ganglioma]. Accessed on: 8 November 2010.</ref>
*May be retroperitoneal.
{{Main|Ganglioneuroma}}
*Multiple ganglioneuromas may be due to [[multiple endocrine neoplasia IIb]].


===Microscopic===
Features:
*Ganglion cells - '''key feature'''.
**Large cells with large nucleus.
***Prominent nucleolus.
*Disordered fibrinous-like material.
*Eosinophilic granular bodies.<ref>R. Kiehl. 8 November 2010.</ref>


Images:
*[http://it.wikipedia.org/wiki/File:Ganglioneuroma_(1).jpg Ganglioneuroma (WC)].
*[http://www.webpathology.com/image.asp?n=4&Case=84 Ganglioneuroma (webpathology.com)].
*[http://en.wikipedia.org/wiki/File:Ganglion_high_mag.jpg Normal ganglion - high mag. (WC)] .


See: ''[[Adrenal gland]]''.
==Meningioma==
 
{{Main|Meningioma}}
==Ependymoma==
===General===
*Called the forgotten glial tumour.
 
Epidemiology:<ref name=Ref_PBoD8_1334>{{Ref PBoD8|1334}}</ref>
*Usual site:
**Adults: usu. spinal cord.
**Children: usu. posterior fossa.
*May be assoc. with [[neurofibromatosis]] 2.
 
Comes in two main flavours:
#Ependymoma (not otherwise specified).
#Myxopapillary ependymoma.
#*Classically at filum terminale.
 
Other flavours:<ref>URL: [http://emedicine.medscape.com/article/1744030-overview http://emedicine.medscape.com/article/1744030-overview]. Accessed on: 17 January 2012.</ref>
*Papillary ependymoma.
*Clear cell ependymoma.
 
===Microscopic===
====Classic ependymoma====
Features:
*Cells have a "tadpole-like" morphology.
**May also be described as ''ice cream cone-shaped''.<ref>[http://www.pathology.vcu.edu/WirSelfInst/tumor-2.html http://www.pathology.vcu.edu/WirSelfInst/tumor-2.html]</ref>
*'''Rosettes''' = circular nuclear free zones/cells arranged in a pseudoglandular fashion; comes in two flavours in ependymoma:
**''Perivascular pseudorosettes'' = (tumour) cells arranged around a blood vessel; nuclei of cells distant from the blood vessel, i.e. rim of cytoplasm (from tumour cells) surround blood vessel (nucleus-free zone); more common than ependymal rosette... but less specific.
**''Ependymal rosette'' ([[AKA]] ''true ependymal rosette'') = rosette has an empty space at the centre - '''key feature'''.
*Nuclear features monotonous, i.e. "boring".<ref>MUN. 6 Oct 2009.</ref>
**There is little variation in size, shape and staining.
 
DDx (classic ependymoma):
*[[Subependymoma]].
*[[Glioblastoma]] (GBM).
**Invasive border = GBM; circumscribed border of lesion = ependymoma.
 
Images:
*www:
**[http://www.flickr.com/photos/ckrishnan/3862487821/in/photostream Ependymoma (flickr.com)].
**[http://www.ajnr.org/cgi/content-nw/full/27/3/488/F10 Ependymoma - ependymal rosettes (ajnr.org)].
**[http://path.upmc.edu/cases/case95/micro.html Anaplastic ependymoma - case 1 (upmc.edu)].
**[http://path.upmc.edu/cases/case324.html Anaplastic ependymoma - case 2 (upmc.edu)].
*WC:
**[http://commons.wikimedia.org/wiki/File:Ependymoma_intermed_mag.jpg Ependymoma - intermed. mag. (WC)].
**[http://commons.wikimedia.org/wiki/File:Ependymoma_low_intermed_mag.jpg Ependymoma - low mag. (WC)].
 
====Myxopapillary ependymoma====
Features:
*Perivascular pseudorosettes:
**Myxoid material surround blood vessels.
***[[Myxoid]] material surrounded by tumour cells.
 
Images:
*[http://commons.wikimedia.org/wiki/File:Myxopapillary_ependymoma_-_high_mag.jpg Myxopapillary ependymoma - high mag. (WC)].
*[http://careers.bmj.com/article-images/cf0708.f2_default.gif Myxopapillary ependymoma (bmj.com)] - part of [http://careers.bmj.com/careers/advice/view-article.html?id=351 careers.bmj.com article on paediatric pathology].
*[http://commons.wikimedia.org/wiki/File:Myxopapillary_ependymoma.jpg Myxopapillary ependymoma - cytology (WC)].
*[http://path.upmc.edu/cases/case626.html Myxopapillary ependymoma - several images (upmc.edu)].
 
====Grading====
Easy:
*Subependymoma = WHO grade I.
*Myxopapillary ependymoma = WHO grade I.
Not-so-easy:
*Classic ependymoma = WHO grade II.
*Anaplastic ependymoma = WHO grade III.
 
Grade II vs. Grade III:
*Cellular density.
*Mitoses.
*Necrosis.
*Microvascular proliferation.
 
Notes:
*Many tumours fall between grade II and grade III.  These are called "indeterminate" by many.
 
===IHC===
*Reticulin.
*GFAP.
*MIB-1.
 
==Subependymoma==
===General===
*Good prognosis - WHO Grade I.
 
===Gross/radiology===
*Classic location: fourth ventricle.<ref>{{Cite journal  | last1 = Hoeffel | first1 = C. | last2 = Boukobza | first2 = M. | last3 = Polivka | first3 = M. | last4 = Lot | first4 = G. | last5 = Guichard | first5 = JP. | last6 = Lafitte | first6 = F. | last7 = Reizine | first7 = D. | last8 = Merland | first8 = JJ. | title = MR manifestations of subependymomas. | journal = AJNR Am J Neuroradiol | volume = 16 | issue = 10 | pages = 2121-9 | month =  | year =  | doi =  | PMID = 8585504 |url=http://www.ajnr.org/cgi/reprint/16/10/2121}}</ref>
*Well demarcated margin.
*Usu. completely within the ventricle; does not extend into brain (like [[ependymoma]]s).
 
===Microscopic===
Features:<ref name=ouhsc>URL: [http://moon.ouhsc.edu/kfung/jty1/Com05/Com501-2-Diss.htm http://moon.ouhsc.edu/kfung/jty1/Com05/Com501-2-Diss.htm]. Accessed on: 2 June 2011.</ref>
*Microcysts with bluish material - give a spongy appearance at low magnification.
*Nuclei cluster.
**Described as "bundles of flowers".
 
Negatives.
*No nuclear pleomorphism, no prominent nucleoli, no mitoses.
 
Images:
*[http://moon.ouhsc.edu/kfung/jty1/Com05/Com05Image/Com501-2-04.gif Subependymoma (ouhsc.edu)].<ref name=ouhsc>URL: [http://moon.ouhsc.edu/kfung/jty1/Com05/Com501-2-Diss.htm http://moon.ouhsc.edu/kfung/jty1/Com05/Com501-2-Diss.htm]. Accessed on: 2 June 2011.</ref>
*[http://commons.wikimedia.org/wiki/File:Subependymoma_-_intermed_mag.jpg Subependyoma - intermed. mag. (WC)].
*[http://commons.wikimedia.org/wiki/File:Subependymoma_-_high_mag.jpg Subependymoma - high mag. (WC)].
 
==Choroid plexus papilloma==
===General===
*Benign - WHO grade I.<ref name=pmid20644273>{{Cite journal  | last1 = Menon | first1 = G. | last2 = Nair | first2 = SN. | last3 = Baldawa | first3 = SS. | last4 = Rao | first4 = RB. | last5 = Krishnakumar | first5 = KP. | last6 = Gopalakrishnan | first6 = CV. | title = Choroid plexus tumors: an institutional series of 25 patients. | journal = Neurol India | volume = 58 | issue = 3 | pages = 429-35 | month =  | year =  | doi = 10.4103/0028-3886.66455 | PMID = 20644273 |URL = http://www.neurologyindia.com/article.asp?issn=0028-3886;year=2010;volume=58;issue=3;spage=429;epage=435;aulast=Menon }}</ref>
*Usu. laternal ventricle in kids.<ref>URL: [http://emedicine.medscape.com/article/250795-overview http://emedicine.medscape.com/article/250795-overview]. Accessed on: 3 June 2011.</ref>
 
===Microscopic===
Features:
*Simple epithelium.
*Papillae.
*Psammoma bodies.
 
Images:
*[http://commons.wikimedia.org/wiki/File:Choroid_plexus_papilloma_micrograph.jpg Choroid plexus papilloma (WC)].
*[http://path.upmc.edu/cases/case551.html Choroid plexus papilloma - oncocytic variant - several images (upmc.edu)].
 
==Choroid plexus carcinoma==
===General===
*Usually pediatric population.
*Malignant counterpart of ''[[choroid plexus papilloma]]''.<ref name=pmid19679976>{{Cite journal  | last1 = Singh | first1 = A. | last2 = Vermani | first2 = S. | last3 = Shruti | first3 = S. | title = Choroid plexus carcinoma: report of two cases. | journal = Indian J Pathol Microbiol | volume = 52 | issue = 3 | pages = 405-7 | month =  | year =  | doi = 10.4103/0377-4929.55009 | PMID = 19679976 }}</ref>
*Poor prognosis - WHO grade III.<ref name=pmid20644273>{{Cite journal  | last1 = Menon | first1 = G. | last2 = Nair | first2 = SN. | last3 = Baldawa | first3 = SS. | last4 = Rao | first4 = RB. | last5 = Krishnakumar | first5 = KP. | last6 = Gopalakrishnan | first6 = CV. | title = Choroid plexus tumors: an institutional series of 25 patients. | journal = Neurol India | volume = 58 | issue = 3 | pages = 429-35 | month =  | year =  | doi = 10.4103/0028-3886.66455 | PMID = 20644273 |URL = http://www.neurologyindia.com/article.asp?issn=0028-3886;year=2010;volume=58;issue=3;spage=429;epage=435;aulast=Menon }}</ref>
*Classically posterior fossa.
*Intraventricular mass.
 
===Microscopic===
Features:<ref name=pmid19679976/>
*Choroid plexus epithelium with [[nuclear pleomorphism]] & high [[NC ratio]].
*Mitoses.
*Necrosis.
*+/-Brain invasion.
 
DDx:
*[[Choroid plexus papilloma]].
*Atypical plexus papilloma - has features intermediate between ''choroid plexus papilloma'' and ''choroid plexus carcinoma''.<ref name=pmid20644273/>
*[[Atypical teratoid/rhabdoid tumour]].
 
Images:
*[http://path.upmc.edu/cases/case198/micro.html Choroid plexus carcinoma - several images (upmc.edu)].
 
===IHC===
Features:<ref name=pmid20644273/>
*Cytokeratins +ve.
*EMA usu. -ve.
*GFAP -ve (~20% +ve).
*Ki-67 high.
**Useful to diff. from benign counterpart.
*INI1 +ve.


==Chordoma==
==Chordoma==
===General===
{{Main|Chordoma}}
*Location: usually sacrum or clivus.
 
===Microscopic===
Features:<ref name=Ref_DCHH184>{{Ref DCHH|184}}</ref>
*Architecture: islands of cells surrounded by fibrous tissue.
**Also described as "lobulated" architecture; may not be apparent.
*[[Myxoid]] background - grey extracellular material, variable amount present.
*Mixed cell population:
*#Abundant eosinophilic cytoplasm.
*#''Physaliphorous cells'' or ''bubble cells'' - '''key feature'''.
*#*Have a very large clear bubble with a sharp border; bubble does not compress nucleus - nucleus may be in bubble.
 
DDx:
*[[Chondrosarcoma]].
 
Images:
*[[WC]]:
**[http://commons.wikimedia.org/wiki/File:Chordoma_-_low_mag.jpg Chordoma - low mag. (WC)].
**[http://commons.wikimedia.org/wiki/File:Chordoma_-_high_mag.jpg Chordoma - high mag. (WC)].
*www:
**[http://library.med.utah.edu/WebPath/COW/COW062.html Chordoma (med.utah.edu)].
**[http://www.ucl.ac.uk/cancer/research-groups/genetics-of-sarcoma/index.htm Chordoma - several images (acl.ac.uk)].
**[http://path.upmc.edu/cases/case64.html Chordoma (upmc.edu)].
**[http://path.upmc.edu/cases/case312/micro.html Chordoma - sacrum - several images (upmc.edu)].
 
===IHC===
Features:<ref>URL: [http://path.upmc.edu/cases/case312/micro.html http://path.upmc.edu/cases/case312/micro.html]. Accessed on: 14 January 2012.</ref>
*S100 +ve.
*AE1/AE3 +ve.
*Brachyury +ve -- '''key stain'''.
**Protein important for axial development, affects notochord development.<ref>URL:[http://www.ncbi.nlm.nih.gov/omim/601397 http://www.ncbi.nlm.nih.gov/omim/601397]. Accessed on: 18 May 2010.</ref>
**''Brachyury'' literally means ''short tail''.<ref>URL: [http://www.jstor.org/pss/86845 http://www.jstor.org/pss/86845]. Accessed on: 18 May 2010.</ref>


==Hemangioblastoma==
==Hemangioblastoma==
===General===
{{Main|Hemangioblastoma}}
*Usually ''cerebellar''.
*Associated with [[von Hippel-Lindau syndrome]].
*WHO grade I.<ref>URL: [http://www.expertconsultbook.com/expertconsult/ob/book.do?method=display&type=bookPage&decorator=none&eid=4-u1.0-B978-1-4160-4580-9..00019-8--sc0155&isbn=978-1-4160-4580-9 http://www.expertconsultbook.com/expertconsult/ob/book.do?method=display&type=bookPage&decorator=none&eid=4-u1.0-B978-1-4160-4580-9..00019-8--sc0155&isbn=978-1-4160-4580-9]. Accessed on: 9 December 2010.</ref>
 
===Microscopic===
Features:<ref>URL: [http://emedicine.medscape.com/article/340994-media http://emedicine.medscape.com/article/340994-media]. Accessed on: 23 June 2010.</ref>
*Vascular.
*Polygonal stromal cells with:
**Hyperchromatic nuclei.
**Vacuolar cytoplasm.
 
DDx:
*Metastatic [[clear cell renal cell carcinoma]].
 
Images:
*[[WC]]:
**[http://commons.wikimedia.org/wiki/File:Cerebellar_hemangioblastoma_intermed_mag.jpg Hemangioblastoma - intermed. mag. (WC)].
**[http://commons.wikimedia.org/wiki/File:Cerebellar_hemangioblastoma_high_mag.jpg Hemangioblastoma - high mag. (WC)].
**[http://commons.wikimedia.org/w/index.php?title=File:Hemangioblastoma_-_nse_-_intermed_mag.jpg Hemangioblastoma - NSE - intermed. mag. (WC)].
*www:
**[http://path.upmc.edu/cases/case342.html Hemangioblastoma - several images (upmc.edu)].
 
===IHC===
Features:<ref>URL: [http://www.nature.com/modpathol/journal/v18/n6/full/3800351a.html http://www.nature.com/modpathol/journal/v18/n6/full/3800351a.html]. Accessed on: 9 December 2010.</ref>
*Alpha-inhibin +ve (cytoplasm).
*EMA -ve.
**RCC typically +ve.
*NSE +ve (nucleus + cytoplasm).
**RCC typically -ve.
 
==Medulloblastoma==
===General===
*Mostly paediatric population.
*May be seen as a component of [[nevoid basal cell carcinoma syndrome]] (NBCCS).
 
===Gross===
*Location: cerebellum - '''key feature'''.
**Morphologically identical supratentorial tumours are called ''[[primitive neuroectodermal tumour]]'' (PNET).
 
===Microscopic===
Features:<ref>URL: [http://moon.ouhsc.edu/kfung/jty1/neurotest/Q93-Ans.htm http://moon.ouhsc.edu/kfung/jty1/neurotest/Q93-Ans.htm]. Accessed on: 26 October 2010.</ref>
*[[Small round cell tumour]].
*Homer-Wright [[rosette]]s:
**Rosette with a meshwork of fibers (neuropil) at the centre.<ref>{{cite journal |author=Wippold FJ, Perry A |title=Neuropathology for the neuroradiologist: rosettes and pseudorosettes |journal=AJNR Am J Neuroradiol |volume=27 |issue=3 |pages=488–92 |year=2006 |month=March |pmid=16551982 |doi= |url=}}</ref>
 
Images:
*[http://moon.ouhsc.edu/kfung/jty1/neurotest/Q93-Ans.htm Medulloblastoma (ouhsc.edu)].
*[http://path.upmc.edu/cases/case667.html Medulloblastoma - several images (upmc.edu)].
*[http://path.upmc.edu/cases/case685.html Medulloblastoma with rhabdomyoblastic differentiation - several images (upmc.edu)].
 
DDx:
*[[Small round cell tumours]].
 
====Subtypes====
*Classic medulloblastoma (~85% of all medulloblastomas).
*Variants of medulloblastoma (~15% of all medulloblastomas together):
*#Anaplastic variant.
*#Large cell variant.
*#Desmoplastic/nodular medulloblastoma (DNMB).
*#Medulloblastoma with extensive nodularity (MBEN).
 
Notes:
*Prognosis:<ref name=pmid18841049>{{cite journal |author=Gulino A, Arcella A, Giangaspero F |title=Pathological and molecular heterogeneity of medulloblastoma |journal=Curr Opin Oncol |volume=20 |issue=6 |pages=668–75 |year=2008 |month=November |pmid=18841049 |doi=10.1097/CCO.0b013e32831369f4 |url=}}</ref><ref name=pmid20940197>{{cite journal |author=Rutkowski S, von Hoff K, Emser A, ''et al.'' |title=Survival and Prognostic Factors of Early Childhood Medulloblastoma: An International Meta-Analysis |journal=J Clin Oncol |volume=28 |issue=33 |pages=4961–4968 |year=2010 |month=November |pmid=20940197 |doi=10.1200/JCO.2010.30.2299 |url=}}</ref> DNMB & MBEN > classic > anaplastic variant, large cell variant.
 
=====Anaplastic variant=====
Features:
*Larger cells.
*Severe anaplasia.
*Polygonal cells.
 
==Primitive neuroectodermal tumour==
*[[AKA]] ''primitive neuroepithelial tumour''. (???)
 
===General===
*Abbreviated ''PNET''.
*Should not be confused with ''peripheral primitive neuroectodermal tumour'' (abbreviated ''[[pPNET]]''<ref name=PST14feb11>PST. 14 February 2011.</ref>), [[AKA]] ''[[Ewing sarcoma]]''.
 
===Microscopic===
Features:
*[[Small round blue cell tumour]] - see ''[[medulloblastoma]]''.
 
DDx:
*[[Embryonal tumour with abundant neuropil and true rosettes]] (ETANTR).<ref name=pmid19563506>{{cite journal |author=Buccoliero AM, Castiglione F, Degl'Innocenti DR, ''et al.'' |title=Embryonal tumor with abundant neuropil and true rosettes: morphological, immunohistochemical, ultrastructural and molecular study of a case showing features of medulloepithelioma and areas of mesenchymal and epithelial differentiation |journal=Neuropathology |volume=30 |issue=1 |pages=84–91 |year=2010 |month=February |pmid=19563506 |doi=10.1111/j.1440-1789.2009.01040.x |url=}}</ref>
 
Images:
*[http://path.upmc.edu/cases/case414.html Primitive neuroectodermal tumour - several images (upmc.edu)].
*[http://path.upmc.edu/cases/case649.html GBM with PNET component - several images (upmc.edu)].
 
==Embryonal tumour with abundant neuropil and true rosettes==
*Abbreviated ''ETANTR''.
===General===
*Super rare.
 
===Microscopic===
Features:
*[[Small round blue cell tumour]].
 
DDx:
*[[Primitive neuroectodermal tumour]].
 
Images:
*[http://path.upmc.edu/cases/case585.html ETANTR - several images (upmc.edu)].
*[http://path.upmc.edu/cases/case666.html ETANTR - another case (upmc.edu)].


==CNS lymphoma==
==CNS lymphoma==
Line 937: Line 614:
*Perivascular clustering.
*Perivascular clustering.


Images:
====Images====
*www:
www:
**[http://frontalcortex.com/?page=image&topic=1&qid=1237 CNS lymphoma (frontalcortex.com)].
*[http://frontalcortex.com/?page=image&topic=1&qid=1237 CNS lymphoma (frontalcortex.com)].
**[http://path.upmc.edu/cases/case403.html Primary CNS lymphoma - several images (upmc.edu)].
*[http://path.upmc.edu/cases/case403.html Primary CNS lymphoma - several images (upmc.edu)].
*[[WC]]:
<gallery>
**[http://commons.wikimedia.org/wiki/File:Primary_CNS_lymphoma_-_high_mag.jpg CNS lymphoma - high mag. (WC)].
Image:Primary CNS lymphoma - low mag.jpg | CNS lymphoma - low mag. (WC)
**[http://commons.wikimedia.org/wiki/File:Primary_CNS_lymphoma_-_low_mag.jpg CNS lymphoma - low mag. (WC)].
Image:Primary CNS lymphoma - intermed mag.jpg | CNS lymphoma - intermed. mag. (WC)
Image:Primary CNS lymphoma - high mag.jpg | CNS lymphoma - high mag. (WC)
Image:Primary CNS lymphoma - very high mag.jpg | CNS lymphoma - very high mag. (WC)
</gallery>
<gallery>
Image: CNS lymphoma (1) B-cell type.jpg | CNS lymphoma. (WC/KGH)
Image: CNS lymphoma (2) B-cell type.jpg | CNS lymphoma. (WC/KGH)
</gallery>


===IHC===
===IHC===
Line 949: Line 633:


Common pattern:
Common pattern:
*CD20 +ve - key stain.
*[[CD20]] +ve - key stain.
*CD3 -ve.
*CD3 -ve.
*Ki-67 ~40%.
*Ki-67 ~40%.
Line 955: Line 639:
*Bcl-1 -ve.
*Bcl-1 -ve.


==Neurocytoma==
===General===
*Rare.
===Microscopic===
Features:<ref>URL: [http://moon.ouhsc.edu/kfung/jty1/Composites/FNA0IE14-Neurocytoma-Micro.htm http://moon.ouhsc.edu/kfung/jty1/Composites/FNA0IE14-Neurocytoma-Micro.htm]. Accessed on: 12 October 2011.</ref>
*[[Pineocytoma|Pineocytomatous]]/neurocytic rosette = irregular rosette with a large meshwork of fibers (neuropil) at the centre.<ref name=pmid16551982>{{cite journal |author=Wippold FJ, Perry A |title=Neuropathology for the neuroradiologist: rosettes and pseudorosettes |journal=AJNR Am J Neuroradiol |volume=27 |issue=3 |pages=488–92 |year=2006 |month=March |pmid=16551982 |doi= |url=}}</ref>
**Similar to Homer-Wright rosette.
*Perinuclear clearing.
*Well-defined cell borders.


DDx:
*[[Oligodendroglioma]] - do not have the characteristic rosettes.
*[[Ganglioglioma]].
*[[Ependymoma]].
Images:
*[http://moon.ouhsc.edu/kfung/jty1/Composites/FNA0IE14-Neurocytoma-Micro.htm Neurocytoma (ouhsc.edu)].
*[http://path.upmc.edu/cases/case383.html Neurocytoma - several images (upmc.edu)].
*[http://path.upmc.edu/cases/case561.html Neurocytoma - cerebellar - several images (upmc.edu)].
===IHC===
*Syaptophysin +ve.
**Most glial tumour -ve.<ref>URL: [http://path.upmc.edu/cases/case383/dx.html http://path.upmc.edu/cases/case383/dx.html]. Accessed on: 15 January 2012.</ref>
==Central neurocytoma==
===General===
*Rare.
===Gross/radiology===
*Intraventricular.<ref>URL: [http://moon.ouhsc.edu/kfung/jty1/Com/Com307-1-Diss.htm http://moon.ouhsc.edu/kfung/jty1/Com/Com307-1-Diss.htm]. Accessed on: 12 January 2012.</ref>
===Microscopic===
Features:<ref>URL: [http://moon.ouhsc.edu/kfung/jty1/Com/Com307-1-Diss.htm http://moon.ouhsc.edu/kfung/jty1/Com/Com307-1-Diss.htm]. Accessed on: 27 May 2011.</ref>
*Perivascular pseudorosette = circular/flower-like arrangement of cells with blood vessel at the centre.<ref name=pmid16551982>{{cite journal |author=Wippold FJ, Perry A |title=Neuropathology for the neuroradiologist: rosettes and pseudorosettes |journal=AJNR Am J Neuroradiol |volume=27 |issue=3 |pages=488–92 |year=2006 |month=March |pmid=16551982 |doi= |url=}}</ref>
*Islands of neuropil.
*Polygonal cells with a perinuclear halo.
DDx:
*[[Oligodendroglioma]].
DDx of perivascular pseudorosette:
*Ependymoma.
*[[Medulloblastoma]], PNET.
*[[Glioblastoma]]s.
Images:
*[http://moon.ouhsc.edu/kfung/jty1/Com/Com307-1-Diss.htm Central neurocytoma - several images (ouhsc.edu)].
*[http://frontalcortex.com/?page=image&topic=1&qid=1203 Central neurocytoma (frontalcortex.com)].
*[http://path.upmc.edu/cases/case74/micro.html Central neurocytoma - crappy images (upmc.edu)].
==Ganglioglioma==
:'''Not''' to be confused with ''[[ganglioneuroma]]''.
===General===
*Rare.
*Usu. temporal lobe.
*Recognized as a cause of [[epilepsy]].<ref name=pmid12125968>{{Cite journal  | last1 = Im | first1 = SH. | last2 = Chung | first2 = CK. | last3 = Cho | first3 = BK. | last4 = Lee | first4 = SK. | title = Supratentorial ganglioglioma and epilepsy: postoperative seizure outcome. | journal = J Neurooncol | volume = 57 | issue = 1 | pages = 59-66 | month = Mar | year = 2002 | doi =  | PMID = 12125968 }}</ref>
===Microscopic===
Features:
*Atypical neurons.
*Atypical glia.
Images:
*[http://path.upmc.edu/cases/case142.html Ganglioglioma - case 1 (upmc.edu)].
*[http://path.upmc.edu/cases/case282.html Ganglioglioma - case 2 (upmc.edu)].
==Lhermitte-Duclos disease==
*Abbreviated ''LDD''.
===General===
*Cerebellar lesion.
*May be associated with [[Cowden syndrome]].<ref name=omim158350>{{OMIM|158350}}</ref>
===Microscopic===
Features:<ref>URL: [http://path.upmc.edu/cases/case472.html http://path.upmc.edu/cases/case472.html]. Accessed on: 21 January 2012.</ref>
*Large (polygonal) cells with round nuclei and prominent nucleoli in the inner (granular) layer - '''key feature'''.
*The outer (molecular) layer has increased cellularity.
*+/-Microcalcifications.
Images:
*[http://path.upmc.edu/cases/case472.html LDD - several images (upmc.edu)].


==Ganglioneuroblastoma==
==Ganglioneuroblastoma==
{{Main|Neuroblastoma}}
===General===
===General===
*Uncommon.
*Uncommon.
*Part of the ''neuroblastic tumours'' group which includes:<ref name=pmid10421272>{{cite journal |author=Shimada H, Ambros IM, Dehner LP, Hata J, Joshi VV, Roald B |title=Terminology and morphologic criteria of neuroblastic tumors: recommendations by the International Neuroblastoma Pathology Committee |journal=Cancer |volume=86 |issue=2 |pages=349–63 |year=1999 |month=July |pmid=10421272 |doi= |url=}}</ref>
**[[Ganglioneuroma]] (benign).
**Ganglioneuroblastoma (intermediate).
**[[Neuroblastoma]] (aggressive).


===Microscopic===
===Microscopic===
Line 1,044: Line 654:
*Ganglion-like cells with a prominent nucleolus.
*Ganglion-like cells with a prominent nucleolus.
*Small undifferentiated cells with scant cytoplasm.
*Small undifferentiated cells with scant cytoplasm.
 
<gallery>
Image:Adrenal Ganglioneuroblastoma LP CTR.jpg|thumb|Adrenal Ganglioneuroblastoma  - Low power (SKB)
Image:Adrenal Ganglioneuroblastoma MP CTR.jpg|thumb|Adrenal Ganglioneuroblastoma  - Medium power (SKB)
Image:Adrenal Ganglioneuroblastoma HP CTR.jpg|thumb|Adrenal Ganglioneuroblastoma - High power (SKB)
Image:Adrenal Ganglioneuroblastoma HP3 CTR.jpg|thumb|Adrenal Ganglioneuroblastoma - High power (SKB)
Image:Adrenal Ganglioneuroblastoma HP2 CTR.jpg|thumb|Adrenal Ganglioneuroblastoma  - High power (SKB)
</gallery>
Images:
Images:
*[http://path.upmc.edu/cases/case530.html Ganglioneuroblastoma - several images (upmc.edu)].
*[http://path.upmc.edu/cases/case530.html Ganglioneuroblastoma - several images (upmc.edu)].

Latest revision as of 09:04, 14 April 2022

A brain stem astrocytoma. (WC)

The article covers tumours in neuropathology. Tumours are a large part of neuropathology. Cytopathology of CNS tumours is dealt with in the article CNS cytopathology.

There are separate articles for peripheral nerve sheath tumours and pituitary/peri-pituitary lesions.

Brain tumours - overview

Alphabetical

For overview see here

By age group

Adult

Four most common types of brain tumours:[1]

  1. Metastatic brain tumours (barely edges out primary tumours)
  2. Glioblastoma, IDH-wildtype.
  3. Astrocytoma, IDH-mutant.
  4. Meningioma.

Children

  1. Pilocytic astrocytoma.
  2. Medulloblastoma.
  3. Ependymoma.
  4. Pontine glioma, often Diffuse midline glioma, H3 K27-altered.

By location

Certain tumours like to hang-out at certain places:[2]

Cerebrum

Cerebellum

Sella turcica

less common:

Spinal cord

Filum terminale

Meninges

less common:

  • Melanoma / Melanocytoma.
  • Lymphoproliferative diseases.
  • Sarcoidosis
  • Arachnoid cyst.
  • Disseminated oligodendroglial-like leptomeningeal tumour.
  • Desmoplastic infantile astrocytoma / ganglioglioma.
  • Meningioangiomatosis.
  • Calcifying pseudoneoplasm.

Skull

Skull base / Cerebellopontine angle

less common:

Primary versus secondary

  • AKA (primary) brain tumour versus metastatic cancer.

Primary

Glial tumours:

  • Cytoplasmic processes - key feature.
    • Best seen at highest magnification - usu. ~1 micrometer.
    • Processes may branch.
  • Ill-defined border/blend with the surrounding brain.

Meningioma:

  • Lesion often dura-based.
  • Mesenchymal tumor (often contains collagen).

Lymphoma:

  • Primary CNS Lymphoma (PCNSL) is usu. a diffuse large B-cell lymphoma.
  • Large (lymphoid) cells, ergo usu. not a difficult diagnosis.
    • ~2x size of resting lymphocyte, nucleoli.
  • Lesion predominantly perivascular.

Secondary

  • Carcinomas:
    • Well-demarcated border between brain and lesion - key feature.
    • No cytoplasmic processes.
    • Usu. have nuclear atypia of malignancy.
    • Nuclei often ~3-4x the size of a RBC.
    • +/-Glandular arrangement.
    • +/-Nucleoli.
  • Melanoma.
  • Secondary Lymphoma.
  • Sarcomas (rare).

By growth pattern

Infiltrative astrocytomas

Notes:

    • Glial: "blends into brain"/gradual transition to non-tumour brain.

Non-infiltrative astrocytomas

Cystic tumours

DDx:[3]


Notes:

    • Non-glial: no radiating glial processes.
  • Rosenthal fibres within the tumour... often seen in pilocytic astrocytoma.
    • Rosenthal fibres may be seen around a (very) slow growing tumour and represent a reactive process.
  • Inflammatory cells and macrophages should prompt consideration of an alternate diagnosis (e.g. cerebral infarct, multiple sclerosis) - esp. if this is a primary lesion.[5]

Grading

Nuclear pleomorphism present:

  • At least grade II (diffuse astrocytoma).

Mitotic figures present:

  • At least grade III (anaplastic astrocytoma).

Microvascular proliferation or necrosis with pseudopalisading tumour cells:

  • Grade IV (glioblastoma AKA glioblastoma multiforme).

Notes:

  • Pseudopalisading tumour cells = high tumour cell density adjacent to regions of necrosis; palisade = a fence of poles forming a defensive barrier or fortification.
  • WHO Grading is currently based on expected biologiocal behaviour without treatment.
    • Grading does not reflect molecular divergent groups within a tumor class or response to therapy (Currently controversies in grading for IDH-mutant astrocytoma vs. IDH-wildtype astrocytoma).[6]

By IHC

Common neuropathology tumours in a table

Type Key feature(s) Imaging History Notes IHC Images
Normal tissue cells regularly spaced, no nuc. atypia small lesion? / deep lesion? variable missed lesion? nil
Normal. (WC)
Reactive astrocytes astrocytes with well-demarcated eosinophilic cytoplasm, regular spacing, no nuc. atypia small lesion? / deep lesion? variable missed lesion / close to a lesion; non-specific pathologic process - need more tissue GFAP
Reactive astrocytes. (WC)
Schwannoma cellular areas (Antoni A), paucicelluar areas (Antoni B), palisading of nuclei (Verocay bodies) extra-axial + intradural old or young need frozen section to Dx, DDx: meningioma S100, SOX10
Schwannoma. (WC)
Meningioma whorls, psammomatous calcs, nuclear inclusions extra-axial + intradural old or young may be diagnosed on smear, DDx: schwannoma, choroid plexus EMA, PR, Ki-67
Meningioma. (WC)
Astrocytoma, IDH-mutant (CNS WHO grade 2 or grade 3) glial processes (esp. on smear), nuclear atypia (typical size var. ~3x, irreg. nuc. membrane, hyperchromasia), no Rosenthal fibres in the core of the lesion †, no microvascular proliferation, no necrosis often enhancing (suggests high grade), usu. supratentorial, usu. white matter usu. old, occ. young common IDH-1(R132H)+/-, GFAP+
High-grade astrocytoma. (WC)
Glioblastoma, IDH-wildtype (CNS WHO grade 4) glial processes (esp. on smear), nuclear atypia (typical size var. ~3x, irreg. nuc. membrane, hyperchromasia), no Rosenthal fibres in the core of the lesion †, microvascular proliferation or necrosis often enhancing (suggests high grade), usu. supratentorial, usu. white matter usu. old, occ. young very common, esp. glioblastoma IDH-1+/-, GFAP+
Glioblastoma. (WC)
Metastasis sharp interface with brain, often glandular, +/-nucleoli, no glial processes often cerebellular, well-circumscribed usu. old often suspected to have metastatic disease TTF-1, CK7, CK20, BRST-2
Metastasis. (WC)

† Rosenthal fibres at the periphery of a lesion are a non-specific finding seen in chronic processes.

Brain metastasis


Molecular

See also: Molecular Neuropathology

Gliomas

Gliomas, glioneuronal tumours and neuronal tumours are often categorized together.

Astrocytic tumours

Features:[9][10]

  • Glial processes - key feature.
    • Thin stringy cytoplasmic processes - best seen at high power in less cellular areas.
  • No Rosenthal fibres within the tumour itself.

Images:

Depreceated:

Oligodendroglial tumours

Depreceated:

Pediatric-type diffuse high-grade glioma

Pediatric-type diffuse low-grade glioma


Circumscribed astrocytic gliomas

Astroblastoma

  • No WHO grade yet.[11]
  • Very rare superficial tumor of young age.[12]
  • Large, cystic. Pushing margin towards CNS.
  • Vasocentric growth, plump cells with absence of fibrillary pattern.
  • GFAP+ve, Synaptohysin-ve, Olig-2-ve, focally EMA/panCK+ve. MIB-1: 1-18 %.
  • Molecular profile overlaps with classical CNS-PNET.
    • Gene fusions invoving meningioma gene (MN1)[13]


Chordoid glioma of the third ventricle

  • WHO grade II.
  • Slowly growing, non-invasive, in adults.
  • Clusters of epithelioid cells in mucinous stroma.
  • Lymphocytic infiltrates, adjacent Rosenthal fibers.
  • Fibrosis may be present.
  • Few mitoses.
  • GFAP+ve, MIB-1 1-3%.
  • TTF-1+ve.
  • CD34+ve.
  • IDH-1-ve, p53-ve.
  • PRKCA D463H mutations.[14]


Ependymal tumours

Choroid plexus tumours

Other neuroepithelial tumours


Cribiform neuroepithelial tumour

AKA: CRINET.

  • Not listed in the current WHO classification.
  • First description in 2009.[15]
  • Around ventricles.[16]
  • Young children.[17]
  • Small undifferentiated cells arranged in cribriform strands and trabeculae of varying thickness.
  • MAP2+ve, Synaptophysin+ve, CK+/-ve. MIB-1: 30%.
  • INI-1 loss, but no rhabdoid features and good prognosis.
  • Stable genomic profile.[18]

Neuronal and mixed neuronal/glial tumours

Desmoplastic infantile astrocytoma / Desmoplastic infantile ganglioglioma

  • Abbreviated DIA or DIG.
  • ICD-O code: 9412/1
  • Large, superficial, cystic tumor of the infancy.
  • Biologic course corresponds to WHO grade I.
  • Very rare, included in the WHO since 1993.
  • Prominent desmoplastic stroma.
  • Astrocytic cells within stroma.
    • GFAP+.
    • MIB-1 usu. 1%.
  • Frequent BRAF V600E or V600D mutations.[19]
  • Single case with BRAF indel or BRAF fusion.

Cerebellar liponeurocytoma

  • Previously called lipomatous medulloblastoma (name changed in WHO 2000).
  • Mean age: 50 years.
  • As the name states: A tumour of the cerebellum.
    • But cases outside cerebellum reported that would qualify.[20]
  • WHO grade II [21] (upgraded from WHO grade I in 2007)[22]
  • ICD-O code: 9506/1

Histo

  • Advanced neuronal and lipomatous differentiation.
  • Neurocytes: round to oval nuclei with clear cytoplasm.
  • Quite cellular.
  • Mitoses almost absent.

IHC

  • GFAP +/-ve (focal).
  • MAP2 +ve.
  • Synaptophysin +ve.
  • NeuN +ve.
  • MIB-1: usu 1-3%.

Molecular

  • Distinct methylation profile.
  • Recurent losses on 2p and Chr. 14.[23]

DDx

Gangliocytoma

  • Grade I WHO neuronal tumour.
    • ICD-O code: 9492/0
  • Groups of irregular large neurons.
  • Non-neoplastic, reticulin-rich glial stroma.

Ganglioglioma

Not to be confused with ganglioneuroma.

General

  • Gangliolioma: Grade I WHO mixed neuronal-glial tumour (ICD-O code: 9505/1).
  • Anaplastic ganglioglioma: Grade III (ICD-O: 9505/3)
  • Rare (approx. 0.5% of all CNS tumors).
  • Usu. temporal lobe.
  • Predominantly children (mean age: 9 years).
  • Recognized as a cause of epilepsy.[24]
  • Favourable prognosis (survival rates up to 97%)
    • Insufficient data für anaplastic ganglioglioma.

Macroscopic

  • Circumscribed lesion.
  • Usu. contrast enhancing.
  • Solid, but intracortical cysts may be present.
  • Little mass effect.


Microscopic

Features:

  • Dysplastic neurons.
    • Out of regular architecture / abnormal location.
    • Cytomegaly
    • Clustering
    • Binucleated (very occassionally).
  • Atypical glia.
  • Eosinophilic granular bodies.
  • Calcification.
  • Prominent capillary network.
  • Lymphocytic cuffing.
  • May contain some reticulin.
  • Glial component may resemble:
    • Fibrillary astrocytoma.
    • Oligodendroglioma.
    • Pilocytic astrocytoma.

Anaplastic ganglioglioma:

  • Brisk mitotic activity
  • Necrosis

IHC

  • Neurons:
    • MAP2 +ve
    • Synaptophysin +ve
    • Neurofilament +ve
  • Glia:
    • CD34+/-ve
  • BRAF V600E +ve (approx. 25%, mainly ganglion cells).

Molecular

  • BRAF V600E-mutated(approx. 25%).
  • IDH1/2 wt.
  • No 1p/19q codeletion.
  • Usu. Chr. 7 gain.
  • CDKN2A deletions in anaplastic ganglioglioma.

DDx:

  • DNT.
  • Oligodendroglioma.
  • Trapped cortical neurons in diffuse astrocytoma.
  • Papillary glioneuronal tumor.
  • Dysembryoplastic neuroepithelial tumor.

Images

Lhermitte-Duclos disease

  • Abbreviated LDD.
  • AKA dysplastic cerebellar gangliocytoma.[25]
  • AKA dysplastic gangliocytoma of the cerebellum.

Papillary glioneuronal tumour

  • Abbreviated PGNT.
  • A benign, supratentorial tumor of childhood.
    • Biologic course corresponds to WHO grade I.
    • Before WHO 2000, considered a Ganglioglioma variant.
  • Prominent pseudopapillary architecture.
  • Neurocytes to medium-sized ganglion cells.
  • GFAP+ core, GFAP- layer
  • Rosenthal fibers, Eosinophilic Granular bodies and lymphocytic cuffing may be present.

Rosette-forming glioneuronal tumour of the fourth ventricle

  • Abbreviated RGNT.
  • Provisional ICD-O code: 9509/1
  • A rare benign infratentorial tumour of the midline of children and adults.
  • Biologic course corresponds to WHO grade I.
  • Glial component corresponds to pilocytic astrocytoma.
  • Neurocytic rosettes.
  • Eosinopil fibrillary cores / pseudorosettes.
  • GFAP+ in fibrillary areas, Syn+ in rosettes.
  • Neurocytic cells: MAP2+
  • MIB-1 usu. below 3%.

Polymorphous low-grade tumor of the young (PLNTY)

Pineal tumours

Embryonal tumours

DDx:

Peripheral nerve sheath tumours

A classification:[26] Benign:

Malignant:

Ganglioneuroma

Not to be confused with ganglioglioma.


Meningioma

Chordoma

Hemangioblastoma

CNS lymphoma

Classification:

  • Primary CNS lymphoma.
  • Non-primary CNS lymphoma - see lymphoma article.

General - primary CNS

  • Classically periventicular distribution.
  • Usually large B cell; can be considered a type of diffuse large B cell lymphoma (DLBCL).
    • Prognosis of CNS (DLBCL) lymphomas worse than nodal (non-CNS) DLBCL.[28]

Microscopic

Features:

  • Large cell lymphoma.
    • Size = 2x diameter normal lymphocyte.
    • Nucleolus - common.
  • Perivascular clustering.

Images

www:

IHC

Can be subclassified in GCB (germinal centre B-cell-like) and non-GCB by CD10, Bcl-6, MUM1/IRF-4, and Bcl-2.[28]

Common pattern:

  • CD20 +ve - key stain.
  • CD3 -ve.
  • Ki-67 ~40%.
  • Bcl-6 +ve.
  • Bcl-1 -ve.


Ganglioneuroblastoma

General

  • Uncommon.
  • Part of the neuroblastic tumours group which includes:[29]

Microscopic

Features:

  • Ganglion-like cells with a prominent nucleolus.
  • Small undifferentiated cells with scant cytoplasm.

Images:

IHC

  • NSE +ve -- small cells.

Lesions of the sella turcica

Lesions of the sella turcica, the pituitary gland environs, is a topic for it self. The differential diagnosis for lesions in this area includes:

See also

References

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  16. Arnold, MA.; Stallings-Archer, K.; Marlin, E.; Grondin, R.; Olshefski, R.; Biegel, JA.; Pierson, CR.. "Cribriform neuroepithelial tumor arising in the lateral ventricle.". Pediatr Dev Pathol 16 (4): 301-7. doi:10.2350/12-12-1287-CR.1. PMID 23495723.
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  18. Gessi, M.; Japp, AS.; Dreschmann, V.; Zur Mühlen, A.; Goschzik, T.; Dörner, E.; Pietsch, T. (Oct 2015). "High-Resolution Genomic Analysis of Cribriform Neuroepithelial Tumors of the Central Nervous System.". J Neuropathol Exp Neurol 74 (10): 970-4. doi:10.1097/NEN.0000000000000239. PMID 26352987.
  19. Wang, AC.; Jones, DTW.; Abecassis, IJ.; Cole, BL.; Leary, SES.; Lockwood, CM.; Chavez, L.; Capper, D. et al. (Jul 2018). "Desmoplastic Infantile Ganglioglioma/Astrocytoma (DIG/DIA) are Distinct Entities with Frequent BRAFV600 Mutations.". Mol Cancer Res. doi:10.1158/1541-7786.MCR-17-0507. PMID 30006355.
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External links