Difference between revisions of "Thymus"

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[[Image:Thymic corpuscle.jpg|thumb|right|225px|[[Micrograph]] of a thymic corpusle (Hassall's corpusle). [[H&E stain]].]]
[[Image:Thymic corpuscle.jpg|thumb|right|225px|[[Micrograph]] of a thymic corpusle (Hassall's corpusle). [[H&E stain]].]]
'''Thymus''' is an annoying little organ that is in the [[mediastinum]]. It is often removed in pediatric cardiac surgery 'cause it is in the way.  In adults, it is commonly removed 'cause the patient has myasthenia gravis.
'''Thymus''' is a little organ that is in the [[mediastinum]]. It is often removed in pediatric cardiac surgery 'cause it is in the way.  In adults, it is commonly removed 'cause the patient has myasthenia gravis.


=Overview=
=Overview=
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*One of two ''[[primary lymphoid organs]]'' - the other one is the [[bone marrow]].<ref>URL: [http://www.life.umd.edu/classroom/bsci423/song/Lab1.html http://www.life.umd.edu/classroom/bsci423/song/Lab1.html]. Accessed on: 28 March 2012.</ref>
*One of two ''[[primary lymphoid organs]]'' - the other one is the [[bone marrow]].<ref>URL: [http://www.life.umd.edu/classroom/bsci423/song/Lab1.html http://www.life.umd.edu/classroom/bsci423/song/Lab1.html]. Accessed on: 28 March 2012.</ref>
*Thymus involutes after childhood.
*Thymus involutes after childhood.
**The line between ''[[thymoma]]'' and ''persistent normal thymus in the adult'' is not well-defined in the radiologic context.<ref name=pmid25925358>{{Cite journal  | last1 = Araki | first1 = T. | last2 = Nishino | first2 = M. | last3 = Gao | first3 = W. | last4 = Dupuis | first4 = J. | last5 = Hunninghake | first5 = GM. | last6 = Murakami | first6 = T. | last7 = Washko | first7 = GR. | last8 = O'Connor | first8 = GT. | last9 = Hatabu | first9 = H. | title = Normal thymus in adults: appearance on CT and associations with age, sex, BMI and smoking. | journal = Eur Radiol | volume = 26 | issue = 1 | pages = 15-24 | month = Jan | year = 2016 | doi = 10.1007/s00330-015-3796-y | PMID = 25925358 }}</ref>
*May be absent due to genetic abnormalities, e.g. [[DiGeorge syndrome]].
*May be absent due to genetic abnormalities, e.g. [[DiGeorge syndrome]].


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==IHC and thymus==
==IHC and thymus==
Types A, AB, B:<ref name=cjs>CJS. January 2010.</ref>
Types A, AB, B:<ref name=cjs>CJS. January 2010.</ref>
*[[CK7]] -ve, [[CK20]] -ve, CAM5.2 +ve, CK5/6 +ve, p63 +ve, CD5 -ve.
*[[CK7]] -ve, [[CK20]] -ve, CAM5.2 +ve, [[CK5/6]] +ve, [[p63]] +ve, CD5 -ve.


Type C:
Type C:
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==Thymic carcinoma==
==Thymic carcinoma==
*Previously ''Thymic tumour type C''.
{{Main|Thymic carcinoma}}
===General===
*Rare.
*Usually arise ''de novo'', i.e. thymoma is not generally a precursor.
*Risk factors - possibly: [[smoking]], radiation.<ref name=pmid23319214/>
 
===Microscopic===
Features:<ref name=Ref_WMSP147>{{Ref WMSP|147}}</ref>
*Cytologically malignant - variable morphology.
**[[Squamous cell carcinoma]] is the most common (65-73% of cases<ref name=pmid23319214>{{Cite journal  | last1 = Thomas de Montpréville | first1 = V. | last2 = Ghigna | first2 = MR. | last3 = Lacroix | first3 = L. | last4 = Besse | first4 = B. | last5 = Broet | first5 = P. | last6 = Dartevelle | first6 = P. | last7 = Fadel | first7 = E. | last8 = Dorfmuller | first8 = P. | title = Thymic carcinomas: clinicopathologic study of 37 cases from a single institution. | journal = Virchows Arch | volume = 462 | issue = 3 | pages = 307-13 | month = Mar | year = 2013 | doi = 10.1007/s00428-013-1371-y | PMID = 23319214 }}</ref><ref name=pmid23866799>{{Cite journal  | last1 = Zhao | first1 = Y. | last2 = Zhao | first2 = H. | last3 = Hu | first3 = D. | last4 = Fan | first4 = L. | last5 = Shi | first5 = J. | last6 = Fang | first6 = W. | title = Surgical treatment and prognosis of thymic squamous cell carcinoma: a retrospective analysis of 105 cases. | journal = Ann Thorac Surg | volume = 96 | issue = 3 | pages = 1019-24 | month = Sep | year = 2013 | doi = 10.1016/j.athoracsur.2013.04.078 | PMID = 23866799 }}</ref>).
*+/-Squamous differentiation.
 
Notes:
*Staging depends on capsular invasion.
 
DDx:
*[[Thymoma]].
*[[Lung cancer|Lung carcinoma]].
*[[Gastrointestinal stromal tumour]].<ref name=pmid23375402>{{Cite journal  | last1 = Rossi | first1 = V. | last2 = Donini | first2 = M. | last3 = Sergio | first3 = P. | last4 = Passalacqua | first4 = R. | last5 = Rossi | first5 = G. | last6 = Buti | first6 = S. | title = When a thymic carcinoma becomes a GIST. | journal = Lung Cancer | volume = 80 | issue = 1 | pages = 106-8 | month = Apr | year = 2013 | doi = 10.1016/j.lungcan.2013.01.003 | PMID = 23375402 }}</ref>
 
====Images====
*[http://www.webpathology.com/image.asp?n=1&Case=653 Thymic carcinoma - low mag. (webpathology.com)].
*[http://www.webpathology.com/image.asp?n=2&Case=653 Thymic carcinoma - high mag. (webpathology.com)].
*[http://www.webpathology.com/image.asp?n=4&Case=653 Thymic carcinoma - lymphoepithelioma-like - high mag. (webpathology.com)].
 
===IHC===
Features:<ref name=Ref_WMSP147>{{Ref WMSP|147}}</ref>
*CD5 +ve (90% of cases<ref name=pmid23319214/>).<ref name=Ref_PBoD708>{{Ref PBoD|708}}</ref>
*CD117 +ve (87% of cases<ref name=pmid23319214/>).
*CD7 +ve.
*[[TTF-1]] -ve.
 
Note:
*Should stain with keratins.


=See also=
=See also=
48,849

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