Difference between revisions of "Lymph nodes"
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==LN architecture== | ==LN architecture== | ||
Lymph node architecture (superficial to deep):<ref> | Lymph node architecture (superficial to deep):<ref name=Ref_WFH4_206-8>{{Ref WFH4|206-8}}</ref> | ||
*Capsule. | *Capsule. | ||
*Subcapsular sinus. | *Subcapsular sinus. | ||
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==LN follicles== | ==LN follicles== | ||
Types of follicles:<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). | ||
#Secondary follicle - have a ''germinal center'' (pale area) and ''mantle zone'' (rim of darker staining lymphocytes). | #Secondary follicle - have a ''germinal center'' (pale area) and ''mantle zone'' (rim of darker staining lymphocytes). | ||
| Line 31: | Line 31: | ||
==Location and cell types== | ==Location and cell types== | ||
Germinal centers:<ref> | Germinal centers:<ref name=Ref_WFH4_210>{{Ref WFH4|210}}</ref> | ||
*Site of B lymphocyte proliferation; ''follicle center cells''. | *Site of B lymphocyte proliferation; ''follicle center cells''. | ||
**Centroblasts - usually superficial aspect. | **Centroblasts - usually superficial aspect. | ||
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*''Follicular dendritic cells''. | *''Follicular dendritic cells''. | ||
Paracortex:<ref> | Paracortex:<ref name=Ref_WFH4_211>{{Ref WFH4|211}}</ref> | ||
*Site of T lymphocytes. | *Site of T lymphocytes. | ||
*''Interdigitating dendritic cell''. | *''Interdigitating dendritic cell''. | ||
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==B cell cycle== | ==B cell cycle== | ||
B cell cycle/maturation:<ref> | B cell cycle/maturation:<ref name=Ref_WFH4_210>{{Ref WFH4|210}}</ref> | ||
#Centroblast (CB): | #Centroblast (CB): | ||
#*Appearance:<ref>URL: [http://www.healthsystem.virginia.edu/internet/hematology/HessEDD/BenignHematologicDisorders/normal-hematopoietic-cells/Secondary-lymphoid-organs-and-tissues.cfm http://www.healthsystem.virginia.edu/internet/hematology/HessEDD/BenignHematologicDisorders/normal-hematopoietic-cells/Secondary-lymphoid-organs-and-tissues.cfm]. Accessed on: 31 January 2010.</ref> | #*Appearance:<ref>URL: [http://www.healthsystem.virginia.edu/internet/hematology/HessEDD/BenignHematologicDisorders/normal-hematopoietic-cells/Secondary-lymphoid-organs-and-tissues.cfm http://www.healthsystem.virginia.edu/internet/hematology/HessEDD/BenignHematologicDisorders/normal-hematopoietic-cells/Secondary-lymphoid-organs-and-tissues.cfm]. Accessed on: 31 January 2010.</ref> | ||
Revision as of 14:02, 3 August 2010
The lymph node, abbreviated LN, is very important in pathology. It is the site of mets and may be the site of a primary lesion, 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.
LN architecture
Lymph node architecture (superficial to deep):[1]
- Capsule.
- Subcapsular sinus.
- Place where metastatic cells often are found.
- In a normal LN the vessels should be "open", i.e. have a discernible lumen.
- Cortex:
- Follicles (superficial).
- Paracortex (deep).
- Cortical sinuses.
- Medulla:
- Medullary cords.
- Medullary sinuses.
Notes:
- Trabeculae - segment the LN radially, i.e. are spoke-like structures.
LN follicles
Types of follicles:[2]
- Primary follicle - no germinal center (pale area).
- Secondary follicle - have a germinal center (pale area) and mantle zone (rim of darker staining lymphocytes).
Germinal centre
Architecture:
- Paler at medullary aspect. (???)
- Darker at capsular aspect. (???)
Location and cell types
Germinal centers:[3]
- Site of B lymphocyte proliferation; follicle center cells.
- Centroblasts - usually superficial aspect.
- Darker, larger, nucleoli.
- Centrocytes (mid germinal center).
- Cells with cleavage.
- Centrocytes (transforming to immunoblasts) - usually deeper aspect.
- Cells with cleavage.
- Centroblasts - usually superficial aspect.
- Tingible body macrophages - mid germinal center.
- Follicular dendritic cells.
Paracortex:[4]
- Site of T lymphocytes.
- Interdigitating dendritic cell.
Medullary cords (site of immunoglobulin synthesis):
- B lymphocytes.
- Plasma cells.
Mantle zone:
- Memory B cells.
B cell cycle
B cell cycle/maturation:[3]
- Centroblast (CB):
- Appearance:[5]
- Large cells.
- Round nucleus, dark.
- Nucleolus (nucleoli).
- Mitotically active.
- Location:
- Medullary aspect of germinal center.
- Appearance:[5]
- Centrocytes (CC), AKA cleaved cells.
- Appearance:
- Cleaved nucleus
- NOT mitotically active.
- Location:
- Mid germinal center.
- Appearance:
- Immunoblasts or memory B cells.
- Appearance:
- Small lymphocytes.
- Location:
- Peripheral blood, mantle zone.
- Appearance:
Notes:
- Immunoblasts may be T cells or B cells; it is not possible to tell on morphologic grounds, i.e. without IHC.
Image:
Cell types
Follicular dendritic cells:[6]
- Classically found in pairs.
- Large nucleus with:
- Basketweave chromatin pattern.
- Small central nucleolus.
Lymphocytes
- See B cell cycle section.
See also
External links
References
- ↑ Young, Barbara; Lowe, James S.; Stevens, Alan; Heath, John W.; Deakin, Philip J. (2000). Wheaters Functional Histology (4th ed.). Churchill Livingstone. pp. 206-8. ISBN 978-0004881973.
- ↑ Young, Barbara; Lowe, James S.; Stevens, Alan; Heath, John W.; Deakin, Philip J. (2000). Wheaters Functional Histology (4th ed.). Churchill Livingstone. pp. 208. ISBN 978-0004881973.
- ↑ 3.0 3.1 Young, Barbara; Lowe, James S.; Stevens, Alan; Heath, John W.; Deakin, Philip J. (2000). Wheaters Functional Histology (4th ed.). Churchill Livingstone. pp. 210. ISBN 978-0004881973.
- ↑ Young, Barbara; Lowe, James S.; Stevens, Alan; Heath, John W.; Deakin, Philip J. (2000). Wheaters Functional Histology (4th ed.). Churchill Livingstone. pp. 211. ISBN 978-0004881973.
- ↑ URL: http://www.healthsystem.virginia.edu/internet/hematology/HessEDD/BenignHematologicDisorders/normal-hematopoietic-cells/Secondary-lymphoid-organs-and-tissues.cfm. Accessed on: 31 January 2010.
- ↑ Wright CA, Nayler SJ, Leiman G (August 1997). "Cytopathology of follicular dendritic cell tumors". Diagn. Cytopathol. 17 (2): 138–42. PMID 9258622. http://www3.interscience.wiley.com/journal/57062/abstract?CRETRY=1&SRETRY=0.