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__NOTOC__
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{{Thymoma}}
{{Thymoma}}
{{CMG}}; {{AE}} {{AM}} {{AAM}}
{{CMG}}; {{AE}} {{AM}} {{AAM}}{{Sab}}


==Overview==
==Overview==
On gross pathology, a well circumscribed mass that is locally invasive is a characteristic finding of thymoma. On microscopic histopathological analysis, round cells, with ample vacuolated cytoplasms, and fat droplets are characteristic findings of thymoma.
On [[gross pathology]], a well-circumscribed mass, that is locally [[Invasive (medical)|invasive]], is a characteristic finding of thymoma. On [[microscopic]] [[Histopathology|histopathological]] [[analysis]], round [[Cell (biology)|cells]] with ample vacuolated [[Cytoplasm|cytoplasms]] and [[fat]] droplets are characteristic findings of thymoma.


==Pathophysiology==
==Pathophysiology==
===Origin===
*It has been believed that thymic epithelium is derived from both [[ectoderm]]al and [[endoderm]]al stem cells.
*Recent evidence indicates that epithelial populations originate from a common progenitor of endodermal origin.
*Occurrence of more differentiated “committed stem cells” with medullary, cortical or other phenotypes is possible.<ref name="Blackburn-2002">{{Cite journal  | last1 = Blackburn | first1 = CC. | last2 = Manley | first2 = NR. | last3 = Palmer | first3 = DB. | last4 = Boyd | first4 = RL. | last5 = Anderson | first5 = G. | last6 = Ritter | first6 = MA. | title = One for all and all for one: thymic epithelial stem cells and regeneration. | journal = Trends Immunol | volume = 23 | issue = 8 | pages = 391-5 | month = Aug | year = 2002 | doi =  | PMID = 12133801 }}</ref><ref name="Gill-2002">{{Cite journal  | last1 = Gill | first1 = J. | last2 = Malin | first2 = M. | last3 = Holländer | first3 = GA. | last4 = Boyd | first4 = R. | title = Generation of a complete thymic microenvironment by MTS24(+) thymic epithelial cells. | journal = Nat Immunol | volume = 3 | issue = 7 | pages = 635-42 | month = Jul | year = 2002 | doi = 10.1038/ni812 | PMID = 12068292 }}</ref>


===Microscopic Pathology===
=== Physiology ===
On microscopic histopathological analysis, round cells, with ample vacuolated cytoplasms, and fat droplets are characteristic findings of thymoma.
 
{|
*[[Thymus]] is the site of maturation of [[T cell|T cells]].
| [[File:T003.png|x150px|thumb|Histopathological image of [[Thymoma]] type B1. Anterior [[mediastinal mass]] surgically resected. Hematoxylin & eosin stain.]]
* This makes [[thymus]] the primary center responsible for [[adaptive immunity]].
| [[File:T004.png|x150px|thumb|Histopathological image representing a noninvasive [[Thymoma]] type B1, surgically resected. Hematoxylin & eosin.]]
 
| [[File:T005.png|x150px|thumb|Histopathological image of [[Thymoma]] type B1. Anterior mediastinal mass surgically resected. Cytokeratin CAM5.2 immunostain.]]
=== Pathogenesis ===
| [[File:T006.png|x170px|thumb|Micrograph of a [[Thymoma]]. FNA specimen. Field stain.]]
|}


===Gross Pathology===
* The exact [[pathogenesis]] of the [[primary tumor]] development is not completely understood.
On gross pathology, a well circumscribed mass that is locally invasive is a characteristic finding of thymoma.


{|
*[[Primary tumor|Primary tumors]] of [[thymus]] are relatively rare.
| [[File:T007.png|x300px|thumb|Mediastinum: locally invasive, circumscribed [[Thymoma]]. Its cut surface bulges, and is pale tan and faintly lobulated. It invaded the capsule at a few points but still remained within the thymus.]]
* Thymoma is the most common type of [[primary tumor]] of [[thymus]].
|}
* Thymoma is [[Histology|histologically]] comprised of abnormally conditioned [[T cell|T cells]].
* The mingling of these abnormal [[T cell|T cells]] into the [[Circulatory system|circulation]] is believed to be involved in the [[causality]] of the associated [[Autoimmunity|autoimmune disorders]].<ref>{{Cite journal
| author = [[C. Buckley]], [[D. Douek]], [[J. Newsom-Davis]], [[A. Vincent]] & [[N. Willcox]]
| title = Mature, long-lived CD4+ and CD8+ T cells are generated by the thymoma in myasthenia gravis
| journal = [[Annals of neurology]]
| volume = 50
| issue = 1
| pages = 64–72
| year = 2001
| month = July
| pmid = 11456312
}}</ref><ref>{{Cite journal
| author = [[J. V. Souadjian]], [[P. Enriquez]], [[M. N. Silverstein]] & [[J. M. Pepin]]
| title = The spectrum of diseases associated with thymoma. Coincidence or syndrome?
| journal = [[Archives of internal medicine]]
| volume = 134
| issue = 2
| pages = 374–379
| year = 1974
| month = August
| pmid = 4602050
}}</ref>


===Genetic Features===
==Genetics==
'''Genetic alterations reported for the different WHO histological thymoma '''subtypes<ref>{{Cite web  | last =  | first =  | title = http://www.iarc.fr/en/publications/pdfs-online/pat-gen/bb10/BB10.pdf | url = http://www.iarc.fr/en/publications/pdfs-online/pat-gen/bb10/BB10.pdf | publisher =  | date =  | accessdate = 26 February 2014 }}</ref>
'''Genetic Alterations Reported for the Different WHO Histological Thymoma sub-types'''<ref>{{Cite web  | last =  | first =  | title = http://www.iarc.fr/en/publications/pdfs-online/pat-gen/bb10/BB10.pdf | url = http://www.iarc.fr/en/publications/pdfs-online/pat-gen/bb10/BB10.pdf | publisher =  | date =  | accessdate = 26 February 2014 }}</ref>
{| border="1" cellpadding="2"
{| border="1" cellpadding="2"
|-
|-
|width="200pt"|'''WHO Type'''
| width="200pt" |'''WHO Type'''
|width="200pt"|'''Chromosomal Gains'''
| width="200pt" |'''Chromosomal Gains'''
|width="200pt"|'''Chromosomal Losses'''
| width="200pt" |'''Chromosomal Losses'''
|-
|-
|Type A || none || -6p  
!Type A  
|
* None
|
* -6p
|-
|-
|Type AB || none || -5q21-22,-6q,-12p,-16q  
!Type AB  
|
* None
|
* -5q21 - 22
* -6q
* -12p
* -16q
|-
|-
|Type B3 || +1q || -6,-13q  
!Type B3  
|
* +1q
|
* -6
* -13q
|}
|}
{|
==Associated Conditions==
 
Approximately 30% of the [[Patient|patients]] have their thymomas discovered because of a symptomatic associated [[autoimmune disorder]]. These disorders include:<ref>{{Cite web  | last =  | first =  | title = http://www.iarc.fr/en/publications/pdfs-online/pat-gen/bb10/BB10.pdf | url = http://www.iarc.fr/en/publications/pdfs-online/pat-gen/bb10/BB10.pdf | publisher =  | date =  | accessdate = }}</ref>
==Video==
{| {{table}} cellpadding="4" cellspacing="0" style="border:#c9c9c9 1px solid; margin: 1em 1em 1em 0; border-collapse: collapse;"
{{#ev:youtube|wfyixp6JxQM}}
| style="width: 25%;" | '''Type'''
 
| style="width: 75%;" | '''Diseases'''
==Associated Disorders==
Approximately, 30% of patients have their thymomas discovered because they have an associated autoimmune disorder. These disorders include:<ref>{{Cite web  | last =  | first =  | title = http://www.iarc.fr/en/publications/pdfs-online/pat-gen/bb10/BB10.pdf | url = http://www.iarc.fr/en/publications/pdfs-online/pat-gen/bb10/BB10.pdf | publisher =  | date =  | accessdate = }}</ref>
{| {{table}}
| style="width: 25%;"| '''Type'''
| style="width: 75%;"| '''Diseases'''
|-
|-
| Neuromuscular Diseases ||[[Myasthenia gravis]], [[neuromyotonia]], rippling muscle disease, [[polymyositis]]/[[dermatomyositis]], [[encephalitis]] (limbic, cortical and brain stem), [[intestinal pseudoobstruction]]
![[Neuromuscular disease|Neuromuscular diseases]]
|
* [[Myasthenia gravis]]  
* [[Neuromyotonia]]  
* Rippling [[muscle]] [[disease]]
* [[Polymyositis]]/[[dermatomyositis]]  
* [[Encephalitis]] ([[Limbic encephalitis|limbic]], cortical and [[brain stem]])  
* [[Intestinal pseudoobstruction]]
|-
|-
| Haematologic Autoimmune Diseases ||[[Anemia]]: [[pure red cell aplasia]], [[pernicious anemia]], [[hemolytic anemia]], [[aplastic anemia]]. Other isolated cytopenis: [[eosinophils]],[[basophils]], [[neutrophils]], Immunodeficiencies: [[hypogammaglobulinaemia]] +/- T-cell deficiencies ([[Good syndrome]])
![[Hematology|Hematologic]] [[autoimmune diseases]]
|
* [[Anemia]]: [[Pure red cell aplasia]], [[pernicious anemia]], [[hemolytic anemia]], [[aplastic anemia]].  
* Other isolated [[cytopenia]]: [[Eosinophils]], [[basophils]], [[neutrophils]]  
* [[Immunodeficiency|Immunodeficiencies]]: [[Hypogammaglobulinaemia]], [[Good syndrome]]
|-
|-
| Dermatologic Diseases ||[[Pemphigus]] (foliaceus or paraneoplastic), [[lichen planus]], [[alopecia areata]]
![[Dermatologic disorders]]
|
* [[Pemphigus]] (foliaceus or [[paraneoplastic]])  
* [[Lichen planus]]  
* [[Alopecia areata]]
|-
|-
| Endocrine Disorders ||[[Addison disease]], [[graves disease]], [[Cushing's disease]]
![[Endocrine disorders]]
|
* [[Addison disease]]  
* [[Graves disease]]
* [[Cushing's disease]]
|-
|-
| Renal and Hepatic Diseases ||[[Glomerulonephritis]], [[autoimmune hepatitis]]
![[Kidney|Renal]] and [[Liver|hepatic]] [[Disease|diseases]]
|
* [[Glomerulonephritis]]  
* [[Autoimmune hepatitis]]
|-
|-
| Systemic Autoimmune Diseases ||[[SLE]], [[Sjögren's syndrome]], [[systemic sclerosis]], [[graft-versus-host disease]]
![[Systemic]] [[autoimmune diseases]]
|
* [[SLE]]
* [[Sjögren's syndrome]]  
* [[Systemic sclerosis]]  
* [[Graft-versus-host disease]]
|}
|}
==Gross Pathology==
On [[gross pathology]], a well circumscribed mass, that is locally [[Invasive (medical)|invasive]], is a characteristic finding of thymoma.
==Microscopic Pathology==
On [[microscopic]] [[histopathological]] [[analysis]], round [[Cell (biology)|cells]], with ample vacuolated [[Cytoplasm|cytoplasms]], and [[fat]] droplets are characteristic findings of thymoma.
{|
==Video==
{{#ev:youtube|wfyixp6JxQM}}


==References==
==References==
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Latest revision as of 01:16, 16 August 2019

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Amr Marawan, M.D. [2] Ahmad Al Maradni, M.D. [3]Sabawoon Mirwais, M.B.B.S, M.D.[4]

Overview

On gross pathology, a well-circumscribed mass, that is locally invasive, is a characteristic finding of thymoma. On microscopic histopathological analysis, round cells with ample vacuolated cytoplasms and fat droplets are characteristic findings of thymoma.

Pathophysiology

Physiology

Pathogenesis

Genetics

Genetic Alterations Reported for the Different WHO Histological Thymoma sub-types[3]

WHO Type Chromosomal Gains Chromosomal Losses
Type A
  • None
  • -6p
Type AB
  • None
  • -5q21 - 22
  • -6q
  • -12p
  • -16q
Type B3
  • +1q
  • -6
  • -13q

Associated Conditions

Approximately 30% of the patients have their thymomas discovered because of a symptomatic associated autoimmune disorder. These disorders include:[4]

Type Diseases
Neuromuscular diseases
Hematologic autoimmune diseases
Dermatologic disorders
Endocrine disorders
Renal and hepatic diseases
Systemic autoimmune diseases

Gross Pathology

On gross pathology, a well circumscribed mass, that is locally invasive, is a characteristic finding of thymoma.

Microscopic Pathology

On microscopic histopathological analysis, round cells, with ample vacuolated cytoplasms, and fat droplets are characteristic findings of thymoma.

Video

{{#ev:youtube|wfyixp6JxQM}}

References

  1. C. Buckley, D. Douek, J. Newsom-Davis, A. Vincent & N. Willcox (2001). "Mature, long-lived CD4+ and CD8+ T cells are generated by the thymoma in myasthenia gravis". Annals of neurology. 50 (1): 64–72. PMID 11456312. Unknown parameter |month= ignored (help)
  2. J. V. Souadjian, P. Enriquez, M. N. Silverstein & J. M. Pepin (1974). "The spectrum of diseases associated with thymoma. Coincidence or syndrome?". Archives of internal medicine. 134 (2): 374–379. PMID 4602050. Unknown parameter |month= ignored (help)
  3. "http://www.iarc.fr/en/publications/pdfs-online/pat-gen/bb10/BB10.pdf" (PDF). Retrieved 26 February 2014. External link in |title= (help)
  4. "http://www.iarc.fr/en/publications/pdfs-online/pat-gen/bb10/BB10.pdf" (PDF). External link in |title= (help)

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