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'''Lymph nodes''', abbreviated '''LNs''', are very important in pathology. They are the site of [[metastases]] and/or may be the site of a primary tumour, i.e. [[lymphoma]]. | |||
Haematopathology and lymphoma is dealt with in the ''[[haematopathology]]'' article. This article covers the basics of lymph nodes. Lymph node pathology is dealt with in the ''[[lymph node pathology]]'' article. | Haematopathology and lymphoma is dealt with in the ''[[haematopathology]]'' article. This article covers the basics of lymph nodes. Lymph node pathology is dealt with in the ''[[lymph node pathology]]'' article. [[Grossing]] is covered in ''[[lymph node grossing]]''. | ||
== | =Clinical= | ||
===Normal (clinical)=== | |||
*Round. | |||
*"Soft". | |||
*Mobile. | |||
===Pathologic (clinical) - associations=== | |||
*Rubbery = suggestive of lymphoma. | |||
*Tender (hurts when ya touch it) = suggestive of infection. | |||
*Fixed (immobile) = suggestive of [[cancer]], usually carcinoma. | |||
*Hard = suggestive of cancer. | |||
*"Large" - cancer or infection. | |||
**What qualifies for "large" depends on the location in the body. | |||
==Radiologic== | |||
*Ellipical (as opposed to spherical) = may be cancer. | |||
*"Large" = could be cancer or infection. | |||
**What qualifies for "large" depends on the location in the body. | |||
=Gross pathologic exam= | |||
{{Main|Lymph node grossing}} | |||
Normal: | |||
*Firm (relative to adipose tissue). | |||
*Glistening surface when cut. | |||
Pathologic: | |||
*White lesions, especially irregular = suggestive of carcinoma. | |||
*White, glistening, with lobulated surface - "fish flesh" = suggestive of lymphoma. | |||
**Subtle lobulation (~1 mm) on section suggestive of ''[[follicular lymphoma]]''.<ref>Bailey, D. 5 August 2010.</ref> | |||
=Microscopic= | |||
==Lymph node architecture== | |||
Lymph node architecture (superficial to deep):<ref name=Ref_WFH4_206-8>{{Ref WFH4|206-8}}</ref> | Lymph node architecture (superficial to deep):<ref name=Ref_WFH4_206-8>{{Ref WFH4|206-8}}</ref> | ||
*Capsule. | *Capsule. | ||
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Notes: | Notes: | ||
*Trabeculae - segment the LN radially, i.e. are spoke-like structures. | *[[Trabeculae]] - segment the LN radially, i.e. are spoke-like structures. | ||
== | ==Lymph node follicles== | ||
Types of follicles:<ref name=Ref_WFH4_208>{{Ref WFH4|208}}</ref> | Types of follicles:<ref name=Ref_WFH4_208>{{Ref WFH4|208}}</ref> | ||
#Primary follicle - no germinal center (pale area). | #Primary follicle - no germinal center (pale area). | ||
| Line 29: | Line 60: | ||
*Paler at capsular aspect. | *Paler at capsular aspect. | ||
*Darker at medullary aspect. | *Darker at medullary aspect. | ||
Image: | |||
*[http://www.pathpedia.com/education/eatlas/histology/lymph_node/normal-lymph-node-histology-%5B10-ln01-10h%5D.jpeg?Width=600&Height=450&Format=4 Secondary follicle (pathpedia.com)].<ref>URL: [http://www.pathpedia.com/education/eatlas/histology/lymph_node/images.aspx http://www.pathpedia.com/education/eatlas/histology/lymph_node/images.aspx]. Accessed on: 29 October 2012.</ref> | |||
==Location and cell types== | ==Location and cell types== | ||
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Mantle zone: | Mantle zone: | ||
*Memory B cells. | *Memory B cells. | ||
*Usually asymmetrical; thicker, i.e. more mantle cells, at capsular aspect.<ref>DG. 17 August 2010.</ref> | |||
==Cell types== | |||
Follicular dendritic cells:<ref name=pmid9258622>{{cite journal |author=Wright CA, Nayler SJ, Leiman G |title=Cytopathology of follicular dendritic cell tumors |journal=Diagn. Cytopathol. |volume=17 |issue=2 |pages=138–42 |year=1997 |month=August |pmid=9258622 |doi= |url=http://www3.interscience.wiley.com/journal/57062/abstract?CRETRY=1&SRETRY=0}}</ref> | |||
*Classically found in pairs. | |||
*Large nucleus with: | |||
**Basketweave chromatin pattern. | |||
**Small central nucleolus. | |||
Lymphocytes: | |||
*See ''B lymphocytes'' section. | |||
===B lymphocytes=== | |||
*B cells are best understood in the context of their maturation. | |||
B cell cycle/maturation:<ref name=Ref_WFH4_210>{{Ref WFH4|210}}</ref> | B cell cycle/maturation:<ref name=Ref_WFH4_210>{{Ref WFH4|210}}</ref> | ||
#Centroblast (CB): | #Centroblast (CB): | ||
| Line 77: | Line 124: | ||
Notes: | Notes: | ||
*Immunoblasts may be T cells or B cells; it is not possible to tell on morphologic grounds, i.e. without IHC. | *Immunoblasts may be T cells or B cells; it is not possible to tell on morphologic grounds, i.e. without IHC. | ||
*Memory device: centro'''''cytes''''' are ''light'' (it nearly rhymes). | |||
Image: | Image: | ||
*[http://www.healthsystem.virginia.edu/internet/hematology/HessEDD/BenignHematologicDisorders/normal-hematopoietic-cells/Secondary-lymphoid-organs-and-tissues.cfm Lymphoid organs (healthsystem.virginia.edu)]. | *[http://www.healthsystem.virginia.edu/internet/hematology/HessEDD/BenignHematologicDisorders/normal-hematopoietic-cells/Secondary-lymphoid-organs-and-tissues.cfm Lymphoid organs (healthsystem.virginia.edu)]. | ||
==Cell types== | ===Cell types - table=== | ||
Follicular dendritic | |||
{| class="wikitable" | |||
! Cell | |||
* | ! Location | ||
* | ! Key feature | ||
! Other morphologic | |||
! IHC | |||
! Other | |||
! Image | |||
|- | |||
| Centroblast | |||
| germinal center | |||
| nucleolus | |||
| large cell, darker staining | |||
| CD10+, BCL6+ ??? | |||
| other ? | |||
| image ? | |||
|- | |||
| Centrocyte | |||
| germinal center | |||
| cleavage | |||
| small cell, light staining | |||
| CD10+, BCL6+ ??? | |||
| other ? | |||
| image ? | |||
|- | |||
| Follicular dendritic cell (FDC) | |||
| germinal center | |||
| mesh-like chromatin, usu. beside another one | |||
| large cell, unremarkable/small nucleolus | |||
| CD21+, [[CD23]]+ | |||
| other ? | |||
| image ? | |||
|- | |||
| Tingible body macrophage | |||
| germinal center | |||
| abundant bubbly pale cytoplasm (with junk) | |||
| large cell | |||
| CD68+ | |||
| other ? | |||
| image ? | |||
|- | |||
<!-- | cell | |||
| location | |||
| key feature | |||
| other morphologic | |||
| IHC | |||
| other | |||
| image --> | |||
|} | |||
=Pathology= | |||
{{Main|Lymph node pathology}} | |||
LNs are very important in [[cancer staging]] and are, in many contexts, sampled routinely. | |||
===Sentinel lymph nodes=== | |||
*Abbreviated ''SLN''. | |||
*LN sampling is associated with morbidity; thus, selective LN sampling is preferred. | |||
*The most important LNs in a LN chain, in the context of [[cancer]], are the ones that are adjacent to the tumour; these are known as '''sentinel lymph nodes'''. | |||
*In lymph node positive disease, the most radioactive lymph node may be negative; this happens ~13% of the time in melanoma.<ref name=pmid11314933>{{Cite journal | last1 = McMasters | first1 = KM. | last2 = Reintgen | first2 = DS. | last3 = Ross | first3 = MI. | last4 = Wong | first4 = SL. | last5 = Gershenwald | first5 = JE. | last6 = Krag | first6 = DN. | last7 = Noyes | first7 = RD. | last8 = Viar | first8 = V. | last9 = Cerrito | first9 = PB. | title = Sentinel lymph node biopsy for melanoma: how many radioactive nodes should be removed? | journal = Ann Surg Oncol | volume = 8 | issue = 3 | pages = 192-7 | month = Apr | year = 2001 | doi = | PMID = 11314933 }}</ref> | |||
Use: | |||
*[[Sentinel lymph node sampling in breast cancer|Breast cancer]] - very common. | |||
*[[Malignant melanoma#Sentinel lymph node panel|Malignant melanoma]] - first context in which SLN sampling was done. | |||
===Lymph node metastasis=== | |||
* | {{Main|Lymph node metastasis}} | ||
*Cancer that has spread to a lymph node. | |||
=See also= | |||
*[[Haematopathology]]. | *[[Haematopathology]]. | ||
*[[Lymph node pathology]]. | *[[Lymph node pathology]]. | ||
*[[Basics]]. | *[[Basics]]. | ||
==External links | =References= | ||
{{reflist|2}} | |||
=External links= | |||
*[http://pleiad.umdnj.edu/hemepath/normal_node/normal_node.html Lymph node architecture (umdnj.edu)]. | *[http://pleiad.umdnj.edu/hemepath/normal_node/normal_node.html Lymph node architecture (umdnj.edu)]. | ||
[[Category:Haematopathology]] | [[Category:Haematopathology]] | ||
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