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Chondro-osseous tumours (view source)

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'''Chondro-osseous tumours''' occasionally cross the desk of the pathologist.  They are grouped together as [[bone]] may develop from [[cartilage]].
[[Image:Osteosarcoma - very high mag.jpg|thumb|250px|right|A chondro-osseous tumour ([[osteosarcoma]]). [[H&E stain]].]]
'''Chondro-osseous tumours''' occasionally cross the desk of the pathologist.  They are grouped together as [[bone]] may develop from [[cartilage]].  


Primary bone tumours are rare; the most common bone tumour is [[metastases]].<ref name=Ref_WMSP632>{{Ref WMSP|632}}</ref>   
Primary bone tumours are rare; the most common bone tumour is [[metastases]].<ref name=Ref_WMSP632>{{Ref WMSP|632}}</ref>   
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===Common malignant===
===Common malignant===
*Osteosarcoma.
*[[Osteosarcoma]].
*Chondrosarcoma.
*[[Chondrosarcoma]].
*Ewing's sarcoma.
*[[Ewing's sarcoma]].
*Multiple myeloma.
*[[Multiple myeloma]].
*Metastases.
*[[Metastases]].
**Most common tumours metastatic to bone (mnemonic: ''BLT with Ketchup & Pickles''):  
**Most common tumours metastatic to bone (mnemonic: ''BLT with Ketchup & Pickles''):  
***[[Breast]].  
***[[Breast]].  
Line 61: Line 62:
| ?
| ?
| no stains / may be assoc. with [[FAP]]
| no stains / may be assoc. with [[FAP]]
| Image (???)
| [[Image:Osteoma -- intermed mag.jpg |thumb|center|150px| Osteoma. (WC)]]
|-
|-
| [[Osteoid osteoma]]
| [[Osteoid osteoma]]
| osteoblastic rimming
| osteoblastic rimming
| anastomosing bony trabeculae
| anastomosing bony trabeculae
| <= 1.5 cm, metaphysis
| must be <2 cm,<ref name=pmid25224389>{{Cite journal  | last1 = Yalcinkaya | first1 = U. | last2 = Doganavsargil | first2 = B. | last3 = Sezak | first3 = M. | last4 = Kececi | first4 = B. | last5 = Argin | first5 = M. | last6 = Basdemir | first6 = G. | last7 = Oztop | first7 = F. | title = Clinical and morphological characteristics of osteoid osteoma and osteoblastoma: a retrospective single-center analysis of 204 patients. | journal = Ann Diagn Pathol | volume = 18 | issue = 6 | pages = 319-25 | month = Dec | year = 2014 | doi = 10.1016/j.anndiagpath.2014.08.006 | PMID = 25224389 }}</ref> metaphysis
| painful, NSAIDs remove pain, young
| painful, NSAIDs remove pain, young
| IHC / other
| IHC / other
| [http://commons.wikimedia.org/w/index.php?title=File:Osteoid_osteoma_-_low_mag.jpg low mag.], [http://commons.wikimedia.org/w/index.php?title=File:Osteoid_osteoma_-_high_mag.jpg high mag.]
| [[Image:Osteoid_osteoma_-_high_mag.jpg |thumb|center|150px| Osteoid osteoma. (WC)]]
|-
|-
| [[Osteoblastoma]]
| [[Osteoblastoma]]
| osteoblastic rimming
| osteoblastic rimming
| anastomosing bony trabeculae
| anastomosing bony trabeculae
| > 1.5 cm, metaphysis
| must be >1 cm,<ref name=pmid25224389/> often >=2 cm, metaphysis
| not painful
| not painful
| IHC / other
| IHC / other
| [http://commons.wikimedia.org/wiki/File:Osteoblastoma_-_low_mag.jpg low mag.], [http://commons.wikimedia.org/wiki/File:Osteoblastoma_-_high_mag.jpg high mag.]
| [[Image:Osteoblastoma_-_high_mag.jpg|thumb|center|150px|Osteoblastoma. (WC)]]
|-
|-
| [[Ewing sarcoma]]
| [[Ewing sarcoma]]
Line 84: Line 85:
| usu. diaphysis
| usu. diaphysis
| pediatric, typically 1-10 years
| pediatric, typically 1-10 years
| PAS+, PASD-  
| PAS+, PASD-, [[chromosomal translocations]] (usually t(11;22)(q24;q12)) 
| [http://commons.wikimedia.org/wiki/File:Ewing_sarcoma_-_intermed_mag.jpg intermed. mag.], [http://commons.wikimedia.org/wiki/File:Ewing_sarcoma_-_PAS_-_high_mag.jpg high mag. - PAS]
| [[Image:Ewing_sarcoma_-_PAS_-_high_mag.jpg |thumb|center|150px| Ewing sarcoma. [[PAS stain]]. (WC)]]
|-
|-
| [[Osteosarcoma]]
| [[Osteosarcoma]]
Line 93: Line 94:
| typically 10-30 years, pain, swelling
| typically 10-30 years, pain, swelling
| no stains; many subtypes
| no stains; many subtypes
| [http://commons.wikimedia.org/wiki/File:Osteosarcoma_-_very_high_mag.jpg very high mag.]
| [[Image:Osteosarcoma_-_very_high_mag.jpg |thumb|center|150px|Osteosarcoma. (WC)]]
|-
|-
| [[Giant cell tumour of bone]]
| [[Giant cell tumour of bone]]
Line 101: Line 102:
| 20-45 years old, +/-joint pain, +/-immobility
| 20-45 years old, +/-joint pain, +/-immobility
| IHC / other
| IHC / other
| [http://commons.wikimedia.org/wiki/File:Giant_cell_tumour_of_bone_-_high_mag.jpg high mag.]
| [[Image:Giant_cell_tumour_of_bone_-_high_mag.jpg|thumb|center|150px|Giant cell tumour. (WC)]]
|-
|-
|}
|}
Line 121: Line 122:
| benign / DDx: chondroma, well-diff. chondrosarcoma
| benign / DDx: chondroma, well-diff. chondrosarcoma
| IHC / bone marrow cavity chondroma = ''enchondroma''
| IHC / bone marrow cavity chondroma = ''enchondroma''
| [http://commons.wikimedia.org/wiki/File:Enchondroma_-_very_high_mag.jpg very high mag.]
| [[Image:Enchondroma_-_very_high_mag.jpg |thumb|center|150px| Enchondroma. (WC)]]
|-
|-
| [[Chondroblastoma]]
| [[Chondroblastoma]]
Line 129: Line 130:
| DDx: [[giant cell tumour of bone]]  
| DDx: [[giant cell tumour of bone]]  
| S100+ve, vimentin +ve
| S100+ve, vimentin +ve
| [http://commons.wikimedia.org/wiki/File:Chondroblastoma_-_very_high_mag.jpg very high mag.]
| [[Image:Chondroblastoma_-_very_high_mag.jpg |thumb|center|150px| Chondroblastoma. (WC)]]
|-
|-
| [[Chondrosarcoma]]
| [[Chondrosarcoma]]
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| >40 years old
| >40 years old
| IHC / may be histologically benign looking
| IHC / may be histologically benign looking
| [http://commons.wikimedia.org/wiki/File:Chondrosarcoma_%282%29.jpg high mag.]
| [[Image:Chondrosarcoma_%282%29.jpg |thumb|center|150px|Chondrosarcoma. (WC)]]
|-
|-
|}
|}
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| Clinical
| Clinical
| IHC / other
| IHC / other
| [http://commons.wikimedia.org/wiki/File:Adamantinoma_-_intermed_mag.jpg (WC)]
| [[Image:Adamantinoma_-_intermed_mag.jpg |thumb|center|150px|Adamantinoma. (WC)]]
|-
|-
| [[Diffuse tenosynovial giant-cell tumour]] ([[AKA]] [[PVNS]])
| [[Diffuse tenosynovial giant-cell tumour]] ([[AKA]] [[PVNS]])
Line 173: Line 174:
| Clinical
| Clinical
| IHC / other
| IHC / other
| [http://commons.wikimedia.org/wiki/File:Pigmented_villonodular_synovitis_low_mag.jpg (WC)]
| [[Image:Pigmented_villonodular_synovitis_low_mag.jpg |thumb|center|150px| PVNS. (WC)]]
|-
|-
| [[Brown tumour]]
| [[Brown tumour]]
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| due to hypercalcemia; not a neoplasm
| due to hypercalcemia; not a neoplasm
| IHC / other
| IHC / other
| Image
| [[Image:Brown_tumour_-_low_mag.jpg |thumb|center|150px| Brown tumour. (WC)]]
|-
|-
|}
|}
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=Cartilage=
=Cartilage=
==Chondroma==
==Chondroma==
===General===
{{Main|Chondroma}}
*Benign thingy.
*Usual legs and feet.
*May be difficult to separate from [[chondrosarcoma]].
*Multiple chondromas = ''enchondromatosis''; three distinct syndromes:<ref name=emed_enchondroma>URL: [http://emedicine.medscape.com/article/389224-overview http://emedicine.medscape.com/article/389224-overview]. Accessed on: 25 December 2010.</ref>
**Ollier disease.
**Maffucci syndrome - with [[hemangioma]]s, increased risk of [[chondrosarcoma]].<ref name=omim166000>{{OMIM|166000}}</ref>
**Metachondromatosis - autosomal dominant.
*''Enchondroma'' = chondroma in the marrow space.
 
Clinical:<ref name=emed_enchondroma>URL: [http://emedicine.medscape.com/article/389224-overview http://emedicine.medscape.com/article/389224-overview]. Accessed on: 25 December 2010.</ref>
*Pain.
 
===Radiology===
Features:<ref name=emed_enchondroma>URL: [http://emedicine.medscape.com/article/389224-overview http://emedicine.medscape.com/article/389224-overview]. Accessed on: 25 December 2010.</ref>
*Lytic lesion.
*Usual close to a growth plate.
 
===Microscopic===
Features:
*Ctyologically benign cells is spaced nests.
 
Images:
*[http://commons.wikimedia.org/wiki/File:Enchondroma_-_intermed_mag.jpg Enchondroma - intermed mag. (WC)].
*[http://commons.wikimedia.org/wiki/File:Enchondroma_-_very_high_mag.jpg Enchondroma - very high mag. (WC)].


==Chondroblastoma==
==Chondroblastoma==
===General===
{{Main|Chondroblastoma}}
*Growth plate lesion.
*Sclerotic margin.
*"Young" = growth plates open.
*Typically painful.<ref name=Ref_PCPBoD8_625>{{Ref PCPBoD8|625}}</ref>
 
===Gross===
*Well-defined lesion.
 
Image:
*[http://www.flickr.com/photos/35441329@N05/4052875138/in/set-72157622681280610 Chondroblastoma (flickr.com/humpath)].
 
===Microscopic===
Features:<ref name=Ref_WMSP_642>{{Ref WMSP|642}}</ref>
*Abundant extracellular material - pink on [[H&E stain]] - looks vaguely like cartilage.
*Chondroblasts:
**Nuclear morphology variable: ovoid, folded or grooved.
**Moderate-abundant eosinophilic cytoplasm.
*+/-Calcification surrounds the cell nests ("chickenwire" appearance) - '''classic feature'''.
**Cell nests have a thin pale blue rimming.
*+/-[[Giant cells]].
**May lead to confusion with ''[[giant cell tumour of bone]]''.
 
DDx:
*[[Giant cell tumour of bone]].
*[[Chondroma]].
*Well-differentiated [[chondrosarcoma]].
 
Images:
*[http://commons.wikimedia.org/wiki/File:Chondroblastoma_-_intermed_mag.jpg Chondroblastoma - intermed. mag. (WC)].
*[http://commons.wikimedia.org/wiki/File:Chondroblastoma_-_very_high_mag.jpg Chondroblastoma - very high mag. (WC)].
*[http://img.medscape.com/pi/emed/ckb/orthopedic_surgery/1230552-1254949-996.jpg Chondroblastoma (medscape.com)].<ref name=emed_chondroblastoma>URL: [http://emedicine.medscape.com/article/1254949-diagnosis http://emedicine.medscape.com/article/1254949-diagnosis]. Accessed on: 31 December 2010.</ref>
*[http://img.medscape.com/pi/emed/ckb/orthopedic_surgery/1230552-1254949-997.jpg Chondroblastoma with "chickenwire" appearance (medscape.com)].<ref name=emed_chondroblastoma>URL: [http://emedicine.medscape.com/article/1254949-diagnosis http://emedicine.medscape.com/article/1254949-diagnosis]. Accessed on: 31 December 2010.</ref>
*[http://path.upmc.edu/cases/case494/images/fig2a.jpg Chondroblastoma (upmc.edu)].<ref>URL: [http://path.upmc.edu/cases/case494.html http://path.upmc.edu/cases/case494.html]. Accessed on: 24 January 2012.</ref>
 
===IHC===
Features:<ref name=Ref_WMSP_642>{{Ref WMSP|642}}</ref>
*S100 +ve.
*Vimentin +ve.<ref name=emed_chondroblastoma>URL: [http://emedicine.medscape.com/article/1254949-diagnosis http://emedicine.medscape.com/article/1254949-diagnosis]. Accessed on: 31 December 2010.</ref>


==Chondromyxoid fibroma==
==Chondromyxoid fibroma==
===General===
{{Main|Chondromyxoid fibroma}}
*Benign.
*Teenagers or young adults.
 
===Gross===
*Metaphyseal lesion.
*Well-circumscribed.
 
===Microscopic===
Features:<ref name=Ref_WMSP642>{{Ref WMSP|642}}</ref>
*Spindle cells or stellate cells in a myxoid or chondroid stroma.
 
Images:
*[http://www.webpathology.com/image.asp?n=7&Case=331 Chondromyxoid fibroma - low mag. (webpathology.com)].
*[http://www.webpathology.com/image.asp?case=331&n=8 Chondromyxoid fibroma - high mag. (webpathology.com)].


==Chondrosarcoma==
==Chondrosarcoma==
===General===
{{Main|Chondrosarcoma}}
*Usually a good prognosis.
 
Clinical/epidemiologic features:<ref name=pmid17976362>{{cite journal |author=Skubitz KM, D'Adamo DR |title=Sarcoma |journal=Mayo Clin. Proc. |volume=82 |issue=11 |pages=1409–32 |year=2007 |month=November |pmid=17976362 |doi= |url=http://www.mayoclinicproceedings.com/content/82/11/1409.long}}</ref>
*Usually arise in a (benign) abnormality of cartilage (e.g. osteochondroma, enchondroma).
*May be associated with a syndrome:
**Olier disease (multiple enchondromatosis).
**Maffucci syndrome (multiple enchondromas and hemangiomas).
 
Notes:
*Review article (from oncology perspective): PMID 17545802.
 
====Subtypes====
Several subtypes exist:
*Chondrosarcoma not otherwise specified (NOS).
*Juxtacortical chondrosarcoma.
*Myxoid chondrosarcoma.
*Mesenchymal chondrosarcoma.
*Clear cell chondrosarcoma.
*Dedifferentiated chondrosarcoma.
 
===Microscopic===
Features:<ref>IAV. 26 February 2009.</ref><ref name=Ref_Klatt417>{{Ref Klatt|417}}</ref>
*"Abnormal cartilage":
**+/-Nuclear atypia - high grade lesions.
***High grade lesions:
****Nuclear clearing.
****Nucleoli.
****Hyperchromasia.
***Low/intermediate grade lesions:
****Bi-nucleation.
****Hypochromatic enlarged nuclei.
****Infiltration of lamellar bone ("invasion") - not common - '''diagnostic'''.
**Increased cellularity.
***More cellular than cartilage... but relatively paucicellular compared to other sarcomas.
**Irregular spacing of chondrocytes.
 
Notes:
*Low grade chondrosarcoma are not cytologically malignant; the diagnosis rests mostly on radiologic findings.
**The exception is ''infiltration of lamellar bone'' -- this is diagnostic of chondrosarcoma.<ref>Dickson, B. 28 April 2011.</ref>
 
DDx:
*[[Chordoma]].
*[[Enchondroma]].
*[[Synovial chondromatosis]].
*[[Osteosarcoma]] - esp. [[chondroblastic osteosarcoma]] - has osteoid, may be focal.
 
Images:
*[[WC]]:
**[http://commons.wikimedia.org/wiki/File:Chondrosarcoma_(1).jpg Chondrosarcoma - low mag. (WC)].
**[http://commons.wikimedia.org/wiki/File:Chondrosarcoma_(2).jpg Chondrosarcoma - high mag. (WC)].
**[http://commons.wikimedia.org/wiki/File:Chondrosarcoma_(3).jpg Chondrosarcoma - high mag. (WC)].
*www:
**[http://path.upmc.edu/cases/case168.html Chondrosarcoma (upmc.edu)].
 
====Variants====
=====Mesenchymal chondrosarcoma=====
*Arise in soft tissue; this is where the name comes from.<ref name=pmid14161087>{{cite journal |author=Dowling EA |title=Mesenchymal chondrosarcoma |journal=J Bone Joint Surg Am |volume=46 |issue= |pages=747–54 |year=1964 |month=June |pmid=14161087 |doi= |url=http://www.ejbjs.org/cgi/reprint/46/4/747.pdf}}</ref>
*Rare variant of chondrosarcoma.
 
Microscopic:
Features:
*"White clouds in a blue sky".
 
Image:
*[http://moon.ouhsc.edu/kfung/jty1/opaq/PathQuiz/S0A001-PQ01-M.htm Mesenchymal chondrosarcoma (ouhsc.edu)].
 
=====Myxoid chondrosarcoma=====
Microscopic:
Features:
*[[Chordoma]]-like:
**[[Myxoid]] background.
**Small cells with eosinophilic cytoplasm.
 
DDx:
*Chondroid [[syringoma]].
*Parachordoma.<ref name=pmid10809219>{{cite journal |author=Fisher C |title=Parachordoma exists--but what is it? |journal=Adv Anat Pathol |volume=7 |issue=3 |pages=141–8 |year=2000 |month=May |pmid=10809219 |doi= |url=}}</ref>
*[[Chordoma]]. (???)
 
=====Extraskeletal myxoid chondrosarcoma=====
*Originally thought to be a variant of ''myxoid chondrosarcoma of bone''; however, may not be a chondrosarcoma at all.<ref name=pmid14657948>{{Cite journal  | last1 = Aigner | first1 = T. | last2 = Oliveira | first2 = AM. | last3 = Nascimento | first3 = AG. | title = Extraskeletal myxoid chondrosarcomas do not show a chondrocytic phenotype. | journal = Mod Pathol | volume = 17 | issue = 2 | pages = 214-21 | month = Feb | year = 2004 | doi = 10.1038/modpathol.3800036 | PMID = 14657948 | URL = http://www.nature.com/modpathol/journal/v17/n2/full/3800036a.html  }}</ref>
*Characteristic [[chromosomal translocation]]: t(9;22) CHN-EWS.
 
DDx:
*Chordoma.<ref name=pmid14657948/>
**S-100 +ve (strong).
**EMA +ve.
 
Image:
*[http://www.cttr.org/large/03113.jpg Extraskeletal myxoid chondrosarcoma (cttr.org)].<ref>URL: [http://www.cttr.org/cms/?p=736 http://www.cttr.org/cms/?p=736]. Accessed on: 1 May 2011.</ref>
 
=====Dedifferentiated chondrosarcoma=====
Clinical:
*Abysmal to poor prognosis.
**In one series (22 patients) 5-year survival ~20%.<ref>{{Cite journal  | last1 = Mitchell | first1 = AD. | last2 = Ayoub | first2 = K. | last3 = Mangham | first3 = DC. | last4 = Grimer | first4 = RJ. | last5 = Carter | first5 = SR. | last6 = Tillman | first6 = RM. | title = Experience in the treatment of dedifferentiated chondrosarcoma. | journal = J Bone Joint Surg Br | volume = 82 | issue = 1 | pages = 55-61 | month = Jan | year = 2000 | doi =  | PMID = 10697315 | URL = http://www.jbjs.org.uk/cgi/pmidlookup?view=long&pmid=10697315 }}</ref>
**All dead in two years in another series (25 patients).<ref name=pmid17653766/>
 
Features:<ref name=pmid17653766>{{Cite journal  | last1 = Sopta | first1 = J. | last2 = Dordević | first2 = A. | last3 = Tulić | first3 = G. | last4 = Mijucić | first4 = V. | title = Dedifferentiated chondrosarcoma: our clinico-pathological experience and dilemmas in 25 cases. | journal = J Cancer Res Clin Oncol | volume = 134 | issue = 2 | pages = 147-52 | month = Feb | year = 2008 | doi = 10.1007/s00432-007-0262-5 | PMID = 17653766 }}</ref>
#Poorly differentiated (mesenchymal) malignancy.
#Well-differentiated cartilaginous component.
 
Images:
*[http://path.upmc.edu/cases/case118/micro.html Dedifferentiated chondrosarcoma (upmc.edu)].
 
====Grading====
Features:<ref name=Ref_WMSP643>{{Ref WMSP|643}}</ref>
*Grade I: mild-to-moderate increase of cellularity +/- binucleated cells.
*Grade II: between Grade I and Grade III.
*Grade III: nuclear pleomorphism, mitoses common.
 
===IHC===
*S-100 -ve. (???)


=Bone=
=Bone=
==Osteoma==
==Osteoma==
===General===
{{Main|Osteoma}}
*Benign.
*May be associated with [[familial adenomatous polyposis]].
*Normal bone - unusual location/outgrowth.
 
===Microscopic===
Features:
*Normal bone.


==Osteoid osteoma==
==Osteoid osteoma==
===General===
{{Main|Osteoid osteoma}}
*Benign bone lesion.
 
Clinical:<ref name=Ref_Sternberg4_285>{{Ref Sternberg4|285}}</ref>
*Extremely painful.
**Relieved by NSAIDS.
 
===Gross===
*Bone: femur > tibia > spine > elsewhere.<ref name=uthscsa>URL: http://radiology.uthscsa.edu/CME/ELTXT/OOT/skeletallocation.html http://radiology.uthscsa.edu/CME/ELTXT/OOT/skeletallocation.html]. Accessed on: 7 May 2012.</ref><ref name=radiologyassistant>URL: [http://www.radiologyassistant.nl/en/494e15cbf0d8d http://www.radiologyassistant.nl/en/494e15cbf0d8d]. Accessed on: 7 May 2012.</ref>
*Most common location (in bone): diaphysis.<ref name=uthscsa>URL: http://radiology.uthscsa.edu/CME/ELTXT/OOT/skeletallocation.html http://radiology.uthscsa.edu/CME/ELTXT/OOT/skeletallocation.html]. Accessed on: 7 May 2012.</ref>
 
Images:
*[http://njms2.umdnj.edu/tutorweb/casegifs/ostostgross.jpg Osteoid osteoma - gross (umdnj.edu)].<ref>URL: [http://njms2.umdnj.edu/tutorweb/gross.htm http://njms2.umdnj.edu/tutorweb/gross.htm]. Accessed on: 7 May 2012.</ref>
*[http://radiology.uthscsa.edu/CME/ELTXT/OOT/treatment.html Osteoid osteoma (uthscsa.edu)].
 
===Microscopic===
Features:<ref name=Ref_Sternberg4_285>{{Ref Sternberg4|285}}</ref>
*Anastomosing bony [[trabeculae]] with:
**Variable mineralization.
***Mineralization (calcium '''p'''hosphate) = '''p'''urple on [[H&E stain]].
**Osteoblasts rimming.
***Cells line-up at edge of bone.
 
Note:
*Histomorphologically near identical/indistinguishable from ''[[osteoblastoma]]''.<ref name=Ref_Sternberg4_286>{{Ref Sternberg4|286}}</ref>
 
Images:
*[http://library.med.utah.edu/WebPath/COW/COW211.html Osteoid osteoma - CT scan (med.utah.edu)].
*[http://www.sciencephoto.com/images/imagePopUpDetails.html?pop=1&id=700030210&pviewid=&country=67&search=gschmeissners&matchtype=FUZZY Osteoid osteoma (sciencephoto.com)].
*[http://commons.wikimedia.org/w/index.php?title=File:Osteoid_osteoma_-_low_mag.jpg Osteoid osteoma - low mag. (WC)].
*[http://commons.wikimedia.org/w/index.php?title=File:Osteoid_osteoma_-_high_mag.jpg Osteoid osteoma - high mag. (WC)].


==Osteoblastoma==
==Osteoblastoma==
===General===
{{Main|Osteoblastoma}}
*Benign bone tumour.
 
===Microscopic===
Features:<ref name=Ref_Sternberg4_285>{{Ref Sternberg4|285}}</ref>
*Anastomosing bony [[trabeculae]] with:
**Osteoblasts rimming.
***Cells line-up at edge of bone.
 
Notes:
*Histomorphologically near identical/indistinguishable from ''[[osteoid osteoma]]''.<ref name=Ref_Sternberg4_286>{{Ref Sternberg4|286}}</ref>
*'''Must''' be greater 1.5 cm by definition.<ref name=Ref_Sternberg4_286>{{Ref Sternberg4|286}}</ref>
 
Images:
*[http://commons.wikimedia.org/w/index.php?title=File:Osteoblastoma_-_high_mag.jpg Osteoblastoma - high mag. (WC)].
*[http://commons.wikimedia.org/w/index.php?title=File:Osteoblastoma_-_low_mag.jpg Osteoblastoma - low mag. (WC)].


==Ewing sarcoma==
==Ewing sarcoma==
*[[AKA]] EWS/pPNET, AKA (confusingly) EWS/PNET:
{{Main|Ewing sarcoma}}
**EWS = Ewing sarcoma.
**pPNET = peripheral primitive neuroectodermal tumour.
*EWS and pPNET were once thought to be different tumours.
 
Notes:
*''Peripheral primitive neuroectodermal tumour'' should not be confused with ''[[primitive neuroectodermal tumour]]'', commonly abbreviated ''PNET'', a (supertentorial) brain tumour with similarities to [[medulloblastoma]].
 
===General===
Clinical:
*Painful.
*Usually younger than 20 years.
*Second most common malignant bone tumour in children.
**Most common malignant bone tumour = osteosarcoma (AKA osteogenic sarcoma).
 
Poor prognostic factors:<ref>PST. 14 February 2011.</ref>
*Age (18 years-old+).
*Pelvis (extremity = good).
*>8 cm.
*Metastases.
*EWS-FL1 fusion type 2.
*>90% necrosis.
 
Etiology:
*Unknown origin; hypothesis: Ewing sarcoma arises from mesenchymal stem cell.<ref name=pmid20953407>{{cite journal |author=Lin PP, Wang Y, Lozano G |title=Mesenchymal Stem Cells and the Origin of Ewing's Sarcoma |journal=Sarcoma |volume=2011 |issue= |pages= |year=2011 |pmid=20953407 |pmc=2952797 |doi=10.1155/2011/276463 |url=}}</ref>
 
====Radiology====
Features:<ref name=Ref_WMSP650>{{Ref WMSP|650}}</ref>
*Long bones, diaphyses.
*Destructive.
*"Onion-skin" periosteal reaction.
 
===Microscopic===
Features:<ref>PST. 22 February 2010.</ref>
*Scant clear cytoplasm (contain glycogen -- PAS +ve, PAS-D -ve) - '''key feature'''.
*Round small nucleus.
**Usu. lack nucleoli.
**Usu. minimal-moderate size variation.
*Mitoses (common).
 
Notes:
*It is a [[small round cell tumour]].
*[[Rhabdomyosarcoma]] occasionally has cytoplasmic clearing (due to glycogen).<ref name=PST14feb11>PST. 14 February 2011.</ref>
 
Images:
*[[WC]]:
**[http://commons.wikimedia.org/wiki/File:Ewing_sarcoma_-_very_high_mag.jpg ES - very high mag. (WC)].
**[http://commons.wikimedia.org/wiki/File:Ewing_sarcoma_-_PAS_-_very_high_mag.jpg ES - PAS - very high mag. (WC)].
*www:
**[http://path.upmc.edu/cases/case103.html Ewing sarcoma - case 1 - several images (upmc.edu)].
**[http://path.upmc.edu/cases/case420.html Ewing sarcoma - case 2 - several images (upmc.edu)].
 
===[[IHC]]===
Features:<ref name=Ref_WMSP651>{{Ref WMSP|651}}</ref>
*CD99 +ve -- 1. diffuse, 2. plasma membrane staining; both required -- most specific.
*FLI-1 +ve.<ref name=pmid15001993>{{cite journal |author=Rossi S, Orvieto E, Furlanetto A, Laurino L, Ninfo V, Dei Tos AP |title=Utility of the immunohistochemical detection of FLI-1 expression in round cell and vascular neoplasm using a monoclonal antibody |journal=Mod. Pathol. |volume=17 |issue=5 |pages=547–52 |year=2004 |month=May |pmid=15001993 |doi=10.1038/modpathol.3800065 |url=http://www.nature.com/modpathol/journal/v17/n5/full/3800065a.html}}</ref>
*CD45 -ve.
**Done to r/o [[lymphoma]].
*+/-Neural markers (NSE, synaptophysin, CD57 (??? CD56 ???), S100).
*+/-Cytokeratins.
*Caveolin-1 +ve in ~ 85% of EWS.<ref>PST. 14 February 2011.</ref>
*WT-1 -ve.<ref name=Ref_WMSP286>{{Ref WMSP|286}}</ref>
 
Notes:<ref>PST. 22 February 2010.</ref>
*CD99 +ve
**Plasma membrane staining tumours:
***[[Lymphoblastic lymphoma]]/leukemia.
***[[Angiomatoid fibrous histiocytoma]].
***[[Desmoplastic small round cell tumour]].
**Weak/cytoplasmic staining:
***[[Synovial sarcoma]].
***[[Rhabdomyosarcoma]].
***[[Rhabdoid tumour]].
*FLI-1 +ve:<ref name=pmid15001993/>
**Vascular neoplasms.
**-/+[[Merkel cell carcinoma]].
**-/+Melanoma.
 
===Molecular diagnostics===
Common features:
*''EWS/FLI-1 fusion gene'' formation due to [[translocation]]: ''t(11;22)(q24;q12)''.<ref>URL: [http://atlasgeneticsoncology.org/Tumors/Ewing5010.html http://atlasgeneticsoncology.org/Tumors/Ewing5010.html]. Accessed on: 23 February 2010.</ref><ref name=pmid3163261>{{cite journal |author=Turc-Carel C, Aurias A, Mugneret F, ''et al.'' |title=Chromosomes in Ewing's sarcoma. I. An evaluation of 85 cases of remarkable consistency of t(11;22)(q24;q12) |journal=Cancer Genet. Cytogenet. |volume=32 |issue=2 |pages=229–38 |year=1988 |month=June |pmid=3163261 |doi= |url=}}</ref>
**Often detected by RT-PCR (with EWS 5' and FLI-1 3' primers).
**Type 1 = EWS exon 7 + FLI-1 exon 6; good prognosis.
**Type 2 = others; poor prognosis.
 
Notes:
*The ''t(11;22)(q24;q12)'' is seen in ~90% of EWS/PNET... but also in:
**[[Olfactory neuroblastoma]].
**Small cell osteogenic sarcoma (small cell variant of [[osteosarcoma]]).
**Polyphenotypic tumours.
**[[Rhabdomyosarcoma]].
**[[Neuroblastoma]] (possibly).
*Several other EWS translocations exist.<ref>URL: [http://www.cancerindex.org/geneweb/EWSR1.htm http://www.cancerindex.org/geneweb/EWSR1.htm]. Accessed on: 20 November 2011.</ref>
**ERG,<ref name=omim165080>{{OMIM|165080}}</ref> ETV1, E1AF and FEV.
*Lack of molecular findings does ''not'' exclude Ewing sarcoma.
*Testing:
**A break apart probe for EWS is a common way to look for pathologic change, as it covers almost all variants.
 
===Electron microscopy===
*Primitive cell junctions.
*Clear zone (glycogen lakes).


==Osteosarcoma==
==Osteosarcoma==
*[[AKA]] osteogenic sarcoma.
{{Main|Osteosarcoma}}
 
===General===
*Most common malignant bone tumour in children.
*May be seen in the context of [[Li-Fraumeni syndrome]].
 
Trivia:
*Terry Fox was afflicited by this tumour.
 
====Definition====
*Tumour that makes osteoid.
**Osteoid = (extracellular) organic component of bone, normally produced by osteoblasts (cells which make bone matrix).
 
===Gross===
Classic locations:<ref name=Ref_TN2007_OR43>{{Ref TN2007|OR43}}</ref>
*Distal femur ~ 45%.
*Proximal tibia ~ 20%.
*Proximal humerous ~ 15%.
 
===Microscopic===
Features:
*Cells with malignant features (e.g. nuclear membrane irregularities, marked nuclear size differences, mitoses) surrounded by delicate strands of osteoid.
**Osteoid on H&E: pink, homogenous, "glassy".
**Tumours typically very cellular - when compared to normal bone.
*Large (multinucleated) osteoclast-like giant cells may be seen.<ref>{{cite journal |author=Papalas JA, Balmer NN, Wallace C, Sangueeza OP |title=Ossifying dermatofibroma with osteoclast-like giant cells: report of a case and literature review |journal=Am J Dermatopathol |volume=31 |issue=4 |pages=379-83 |year=2009 |month=June |pmid=19461244 |doi=10.1097/DAD.0b013e3181966747 |url=}}</ref>
 
Images:
*[http://commons.wikimedia.org/wiki/File:Osteosarcoma_-_intermed_mag.jpg Osteosarcoma - intermed. mag. (WC)].
*[http://commons.wikimedia.org/wiki/File:Osteosarcoma_-_very_high_mag.jpg Osteosarcoma - very high mag. (WC)].
*[http://commons.wikimedia.org/wiki/File:Small_cell_osteosarcoma_-_intermed_mag.jpg Small cell osteosarcoma - intermed. mag. (WC)].
*[http://commons.wikimedia.org/wiki/File:Small_cell_osteosarcoma_-_high_mag.jpg Small cell osteosarcoma - high mag. (WC)].
 
====Subtypes====
Subtypes:<ref name=Ref_WMSP638>{{Ref WMSP|638}}</ref><ref>URL: [http://bestpractice.bmj.com/best-practice/monograph/780/basics/classification.html http://bestpractice.bmj.com/best-practice/monograph/780/basics/classification.html]. Accessed on: 7 April 2011.</ref>
*Conventional osteosarcoma (high grade).
**Osteoblastic osteosarcoma.
**[[Fibroblastic osteosarcoma]].
**[[Chondroblastic osteosarcoma]].
*Small cell osteosarcoma.
*[[Telangiectatic osteosarcoma]].
*[[Parosteal osteosarcoma]].
*Periosteal osteosarcoma.
*[[Low-grade central osteosarcoma]].
*High-grade surface osteosarcoma.
*[[Secondary osteosarcoma]].
*Gnathic osteosarcoma - jaw bones - usually chondroblastic.
 
How to remember:
*Convention ''FOC'' = fibroblastic, osteogenic, chondroblastic.
*Low-grade central.
*High-grade surface.
*Parosteal.
*Periosteal.
*Small cell.
*Secondary.
*Telangiectatic.
 
=====Chondroblastic osteosarcoma=====
*Chondroid matrix present - may be prominent; osteoid may be a minor component.
*May be confused with [[chondrosarcoma]].
 
=====Fibroblastic osteosarcoma=====
*[[Undifferentiated pleomorphic sarcoma]]-like/[[MFH]]-like.
 
Images:
*[http://path.upmc.edu/cases/case44.html Fibroblastic osteosarcoma (upmc.edu)].
 
=====Low-grade central osteosarcoma=====
*Well-formed bone.
*Usu. minimal nuclear atypia.
 
DDx:
*[[Fibrous dysplasia]].<ref name=inwards>{{cite journal |author=Inwards, CY |title=Low-grade central osteosarcoma versus fibrous dysplasia |journal=Pathology Case Reviews |volume=6 |issue=1 |pages=22-27 |year=2001 |pmid= |doi= |url= http://journals.lww.com/pathologycasereviews/Fulltext/2001/01000/Low_Grade_Central_Osteosarcoma_Versus_Fibrous.5.aspx }}</ref>
 
=====Telangiectatic osteosarcoma=====
*Rare.<ref name=omim21339678>{{Cite journal  | last1 = Patibandla | first1 = MR. | last2 = Uppin | first2 = SG. | last3 = Thotakura | first3 = AK. | last4 = Panigrahi | first4 = MK. | last5 = Challa | first5 = S. | title = Primary telangiectatic osteosarcoma of occipital bone: a case report and review of literature. | journal = Neurol India | volume = 59 | issue = 1 | pages = 117-9 | month =  | year =  | doi = 10.4103/0028-3886.76891 | PMID = 21339678 }}</ref>
*Extremely vascular.
*Prognosis similar to other types of osteosarcoma.<ref name=pmid17351949>{{Cite journal  | last1 = Weiss | first1 = A. | last2 = Khoury | first2 = JD. | last3 = Hoffer | first3 = FA. | last4 = Wu | first4 = J. | last5 = Billups | first5 = CA. | last6 = Heck | first6 = RK. | last7 = Quintana | first7 = J. | last8 = Poe | first8 = D. | last9 = Rao | first9 = BN. | title = Telangiectatic osteosarcoma: the St. Jude Children's Research Hospital's experience. | journal = Cancer | volume = 109 | issue = 8 | pages = 1627-37 | month = Apr | year = 2007 | doi = 10.1002/cncr.22574 | PMID = 17351949 }}</ref>
 
Important radiologic DDx:
*[[Aneurysmal bone cyst]].
 
=====Parosteal osteosarcoma=====
*Arise from surface of bone.<ref>{{Ref WHOSTAB|279}}</ref>
*Low grade.<ref name=pmid16896870>{{Cite journal  | last1 = Carrle | first1 = D. | last2 = Bielack | first2 = SS. | title = Current strategies of chemotherapy in osteosarcoma. | journal = Int Orthop | volume = 30 | issue = 6 | pages = 445-51 | month = Dec | year = 2006 | doi = 10.1007/s00264-006-0192-x | PMID = 16896870 | PMC = 3172747 | URL = http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3172747/?tool=pubmed}}</ref>
*Well-formed bone.
 
DDx:
*[[Fibrous dysplasia]].{{fact}}
 
=====Periosteal osteosarcoma=====
*Intermediate grade.<ref name=pmid16896870/>
 
=====Small cell osteosarcoma=====
*May mimic (other) [[small round cell tumours]].
 
=====Secondary osteosarcoma=====
Arises in the context of something else - causes:
*[[Paget disease of the bone]] (~80% of secondary osteosarcomas)
*Radiation (~15% of secondary osteosarcomas)).<ref>URL: [http://www.rsna.org/REG/publications/rg/afip/privateM/1997/0017/0005/1205/6.htm http://www.rsna.org/REG/publications/rg/afip/privateM/1997/0017/0005/1205/6.htm]. Accessed on: 8 April 2011.</ref>
*Prognosis often poor.<ref name=pmid16896870/>
 
Images:
*[http://path.upmc.edu/cases/case598.html Secondary osteosarcoma - several images (upmc.edu)].


==Giant cell tumour of bone==
==Giant cell tumour of bone==
===General===
{{Main|Giant cell tumour of bone}}
Features:<ref name=Ref_WMSP648>{{Ref WMSP|648}}</ref>
*Approximately 5% of primary bone tumours.
*Typical age: 20-45 years.
 
====Clinical====
*Location: growth plate of long bones.<ref name=pmid11501745>{{Cite journal  | last1 = Wülling | first1 = M. | last2 = Engels | first2 = C. | last3 = Jesse | first3 = N. | last4 = Werner | first4 = M. | last5 = Delling | first5 = G. | last6 = Kaiser | first6 = E. | title = The nature of giant cell tumor of bone. | journal = J Cancer Res Clin Oncol | volume = 127 | issue = 8 | pages = 467-74 | month = Aug | year = 2001 | doi =  | PMID = 11501745 }}</ref>
**May present with joint pain, immobility.
 
Note:
*Several types of [[giant cell lesions|giant cell tumours]] exist.
 
===Microscopic===
Features:<ref name=Ref_Klatt420>{{Ref Klatt|420}}</ref>
*Giant cells with a large number of nuclei (usu. >10 in the plane of section).
**Usu. have prominent nucleoli.
*Mononuclear cells and small multinucleated cells with nuclei similar to those in the giant cells - '''key feature'''.
*+/-Hemosiderin deposition - not common.<ref name=pmid1939753>{{Cite journal  | last1 = Aoki | first1 = J. | last2 = Moriya | first2 = K. | last3 = Yamashita | first3 = K. | last4 = Fujioka | first4 = F. | last5 = Ishii | first5 = K. | last6 = Karakida | first6 = O. | last7 = Imai | first7 = S. | last8 = Sakai | first8 = F. | last9 = Imai | first9 = Y. | title = Giant cell tumors of bone containing large amounts of hemosiderin: MR-pathologic correlation. | journal = J Comput Assist Tomogr | volume = 15 | issue = 6 | pages = 1024-7 | month =  | year =  | doi =  | PMID = 1939753 }}</ref><ref name=pmid18554912>{{Cite journal  | last1 = Matsushige | first1 = T. | last2 = Nakaoka | first2 = M. | last3 = Yahara | first3 = K. | last4 = Kagawa | first4 = K. | last5 = Miura | first5 = H. | last6 = Ohnuma | first6 = H. | last7 = Kurisu | first7 = K. | title = Giant cell tumor of the temporal bone with intratumoral hemorrhage. | journal = J Clin Neurosci | volume = 15 | issue = 8 | pages = 923-7 | month = Aug | year = 2008 | doi = 10.1016/j.jocn.2007.03.013 | PMID = 18554912 }}</ref>
 
Notes:
*Giant cells typically present in abundance.
 
DDx:
*[[Giant cell lesions]].
**[[Aneurysmal bone cyst]] - typically has spindle cells around the giant cells.
 
Images:
*[http://commons.wikimedia.org/wiki/File:Giant_cell_tumour_of_bone_-_high_mag.jpg GCT of bone - high mag. (WC)].
*[http://commons.wikimedia.org/wiki/File:Giant_cell_tumour_of_bone_-_low_mag.jpg GCT of bone - low mag. (WC)].
 
===IHC===
*p63 +ve in scattered mononuclear cells.<ref name=pmid18311114>{{cite journal |author=Dickson BC, Li SQ, Wunder JS, ''et al.'' |title=Giant cell tumor of bone express p63 |journal=Mod. Pathol. |volume=21 |issue=4 |pages=369–75 |year=2008 |month=April |pmid=18311114 |doi=10.1038/modpathol.2008.29 |url=}}</ref>
**This seems to be contradicted by another paper.<ref name=pmid20012988>{{cite journal |author=Alberghini M, Kliskey K, Krenacs T, ''et al.'' |title=Morphological and immunophenotypic features of primary and metastatic giant cell tumour of bone |journal=Virchows Arch. |volume=456 |issue=1 |pages=97–103 |year=2010 |month=January |pmid=20012988 |doi=10.1007/s00428-009-0863-2 |url=}}</ref>


=Other=
=Other=
This section collects stuff that doesn't neatly fit into the ''bone'' or ''cartilage'' category.
This section collects stuff that doesn't neatly fit into the ''bone'' or ''cartilage'' category.
==Osteochondroma==
===General===
*Benign.
*Very common.
*Abnormal outgrowth of bone and cartilage - associated with growth plate.
*Usually present before age 20.<ref name=pmid12873205>{{Cite journal  | last1 = Parkin | first1 = B. | last2 = Bennett | first2 = JC. | last3 = Zaher | first3 = A. | title = Pathologic quiz case: an iliac mass in a 25-year-old woman. Osteochondroma. | journal = Arch Pathol Lab Med | volume = 127 | issue = 8 | pages = e355-6 | month = Aug | year = 2003 | doi = 10.1043/1543-2165(2003)127e355:PQCAIM2.0.CO;2 | PMID = 12873205 | URL = http://www.archivesofpathology.org/doi/full/10.1043/1543-2165%282003%29127%3Ce355:PQCAIM%3E2.0.CO;2}}</ref>


===Gross===
==Notochordal tumors==
Features:
Notochordal tumors arise from notochordal remnants and thus are seen in the clivus or sacrum.
*Metasphyseal lesions.<ref name=medpath>URL: [http://www.medpath.info/MainContent/Skeletal/Bone_07.html http://www.medpath.info/MainContent/Skeletal/Bone_07.html]. Accessed on: 18 September 2012.</ref>
{{Main|Chordoma}}
**Often distal femur, proximal humerus or proximal tibia.<ref name=pmid12873205/>
**Occasionally iliac mass.<ref name=pmid22217414>{{Cite journal  | last1 = Kokavec | first1 = M. | last2 = Gajdoš | first2 = M. | last3 = Džupa | first3 = V. | title = [Osteochondroma of the iliac crest: case report]. | journal = Acta Chir Orthop Traumatol Cech | volume = 78 | issue = 6 | pages = 583-5 | month =  | year = 2011 | doi =  | PMID = 22217414 }}
</ref>
*Mushroom-like shape - with broad or narrow base.


Note:
==Osteochondroma==
*Very unusual in craniofacial bones.<ref name=pmid12873205/>
{{Main|Osteochondroma}}
 
===Microscopic===
Features:<ref name=pmid12873205/>
*Bone - forms base of "mushroom".
*Cartilage - layer usu. thinner in older individuals.
**Lobular arrangement<ref name=upmc_case341>URL: [http://path.upmc.edu/cases/case341/dx.html http://path.upmc.edu/cases/case341/dx.html]. Accessed on: 19 September 2012.</ref> - clusters of 3-12 lacunae (separated by stroma).
**May have mild atypia.
**Nuclear enlargement - up to 5x normal.
*[[Perichondrium]] - covers the cartilage.
**Thin layer of cells - higher cellular density than cartilage.
***Bland spindle cells in a fibrous (eosinophilic) stroma.
 
Notes:
*Benign cartilage - one chondrocyte per lacuna, small and round nucleus, no binucleation.
 
DDx:
*[[Chondrosarcoma]] - esp. in older individuals.
 
Images:
*[http://path.upmc.edu/cases/case341.html Super rare intracranial mesenchymal osteochondroma - several images (upmc.edu)].<ref name=upmc_case341/>


==Diffuse tenosynovial giant-cell tumour==  
==Diffuse tenosynovial giant-cell tumour==  
*[[AKA]] ''tenosynovial giant-cell tumour, diffuse type''.
*[[AKA]] ''tenosynovial giant-cell tumour, diffuse type''.
*Previously known as ''pigmented villonodular synovitis'' (PVNS).<ref>{{Ref PBoD8|1247}}</ref>  
*Previously known as ''pigmented villonodular synovitis'' (PVNS).<ref>{{Ref PBoD8|1247}}</ref>  
 
{{Main|Diffuse tenosynovial giant-cell tumour}}
===General===
*Course: benign.
*''Giant cell tumor of the tendon sheath'' is considered to be the soft-tissue counterpart of PVNS.<ref>URL: [http://emedicine.medscape.com/article/1253223-overview http://emedicine.medscape.com/article/1253223-overview]. Accessed on: 6 January 2011.</ref>
 
===Microscopic===
Features:<ref>URL: [http://www.wheelessonline.com/ortho/pigmented_villonodular_synovitis http://www.wheelessonline.com/ortho/pigmented_villonodular_synovitis].</ref>
*Subsynovial nodules composed of cells with:
**Abundant cytoplasm.
**Pale nuclei.
*Multinucleated giant cells.
*Hemosiderin-laden macrophages.
*Foam cells.
 
Images:
*[[WC]]:
**[http://commons.wikimedia.org/wiki/File:Pigmented_villonodular_synovitis_low_mag.jpg PVNS - low mag. (WC)].
**[http://commons.wikimedia.org/wiki/File:Pigmented_villonodular_synovitis_high_mag.jpg PVNS - high mag. (WC)].
*www:
**[http://path.upmc.edu/cases/case251/micro.html PVNS - several images (upmc.edu)].


==Giant cell tumour of tendon sheath==
==Giant cell tumour of tendon sheath==
*Abbreviated ''GCT of tendon sheath''.
*Abbreviated ''GCT of tendon sheath''.
===General===
{{Main|Giant cell tumour of tendon sheath}}
*Can be thought of as the small joint version of [[diffuse tenosynovial giant-cell tumour]] ([[AKA]] ''PVNS'').<ref name=Ref_DCHH341>{{Ref DCHH|341}}</ref>
*Rarely recur.
 
===Microscopic===
Features:<ref name=Ref_DCHH341>{{Ref DCHH|341}}</ref>
*+/-Tendon.
**Dense connective tissue.
*Multinucleated giant cells.
*Hemosiderin-laden macrophages.
*Foam cells.
 
DDx:
*[[Giant cell lesions]].
 
Images:
*[http://commons.wikimedia.org/wiki/File:Giant_cell_tumor_of_tendon_sheath_histopathology%281%29.jpg GCT of tendon sheath (WC)].
*[http://www.webpathology.com/image.asp?n=1&Case=484 GCT of tendon sheath - very low mag. (webpathology.com)]
*[http://www.webpathology.com/image.asp?case=484&n=5 GCT of tendon sheath - low mag. (webpathology.com)].
*[http://www.webpathology.com/image.asp?n=4&Case=484 GCT of tendon sheath - high mag. (webpathology.com)].


==Adamantinoma==
==Adamantinoma==
:Should '''not''' be confused with ''[[adenomatoid tumour]]''.
{{Main|Adamantinoma}}
===General===
Features:<ref name=Ref_WMSP650>{{Ref WMSP|650}}</ref>
*Rare: < 1% of bone tumours.
*25-35 years old.
*Tibia, fibula.
*Benign, may be locally aggressive.
*Cousin of [[ameloblastoma]]. (???)
 
===Radiology===
*Intracortical, radiolucent.
 
===Microscopic===
Features:
*Biphasic tumour:
*#Fibrous/spindle cell component.
*#Epithelial component.
 
Images:
*[http://southbaypath.org/CaseImages/sb5260/AdamantinomaBiopsy3.jpg Adamantinoma (southbaypath.org)].<ref>URL: [http://southbaypath.org/CaseImages/sb5260/sb5260.htm http://southbaypath.org/CaseImages/sb5260/sb5260.htm]. Accessed on: 7 December 2010.</ref>
*[http://commons.wikimedia.org/wiki/File:Adamantinoma_-_intermed_mag.jpg Adamantinoma - intermed. mag. (WC)].
 
DDx:<ref name=pathcon_adam>URL: [http://www.pathconsultddx.com/pathCon/diagnosis?pii=S1559-8675%2806%2970057-2 http://www.pathconsultddx.com/pathCon/diagnosis?pii=S1559-8675%2806%2970057-2]. Accessed on: 28 April 2011.</ref>
*Vascular tumours ([[Epithelioid hemangioendothelioma]]).
*Metastatic carcinoma.
 
===IHC===
Features:<ref name=pathcon_adam/>
*CK14 +ve (HMWK).<ref>URL: [http://www.nordiqc.org/Epitopes/Cytokeratins/cytokeratins.htm http://www.nordiqc.org/Epitopes/Cytokeratins/cytokeratins.htm]. Accessed on: 28 April 2011.</ref>
*CK19 +ve (LMWK).
*CK8/18 -ve (LMWK).


==Brown tumour==
==Brown tumour==
Line 960: Line 389:
*[[Giant cell tumour of bone]] and other [[giant cell lesions]].
*[[Giant cell tumour of bone]] and other [[giant cell lesions]].


Images:
====Images====
*www:
<gallery>
**[http://wwwold.path.utah.edu/classes/webpath/bonehtml/bone053.htm Brown tumour (utah.edu)].
Image:Brown_tumour_-_low_mag.jpg | Brown tumour - low mag. (WC)
**[http://www.mda-sy.com/pathology/BONEHTML/BONE054.HTM Brown tumour (mda-sy.com)].
Image:Brown_tumour_-_intermed_mag.jpg | Brown tumour - intermed. mag. (WC)
**[http://path.upmc.edu/cases/case139/micro.html Brown tumour - several images (upmc.edu)].
Image:Brown_tumour_-_high_mag.jpg | Brown tumour - high mag. (WC)
*[[WC]]:
</gallery>
**[http://commons.wikimedia.org/wiki/File:Brown_tumour_-_low_mag.jpg Brown tumour - low mag. (WC)].
www:
**[http://commons.wikimedia.org/wiki/File:Brown_tumour_-_intermed_mag.jpg Brown tumour - intermed. mag. (WC)].
*[http://wwwold.path.utah.edu/classes/webpath/bonehtml/bone053.htm Brown tumour (utah.edu)].
**[http://commons.wikimedia.org/wiki/File:Brown_tumour_-_high_mag.jpg Brown tumour - high mag. (WC)].
*[http://www.mda-sy.com/pathology/BONEHTML/BONE054.HTM Brown tumour (mda-sy.com)].
*[http://path.upmc.edu/cases/case139/micro.html Brown tumour - several images (upmc.edu)].


=See also=
=See also=
Line 982: Line 412:
*[http://www.radiologyassistant.nl/en/494e15cbf0d8d Bone radiology (radiologyassistant.nl)].
*[http://www.radiologyassistant.nl/en/494e15cbf0d8d Bone radiology (radiologyassistant.nl)].


[[Category:Chondro-osseous tumours]]
[[Category:Weird stuff]]
[[Category:Weird stuff]]
Michael
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