Difference between revisions of "Lymph nodes"
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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]]. | '''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= | =Clinical= | ||
| Line 23: | Line 23: | ||
=Gross pathologic exam= | =Gross pathologic exam= | ||
{{Main|Lymph node grossing}} | |||
Normal: | Normal: | ||
*Firm (relative to adipose tissue). | *Firm (relative to adipose tissue). | ||
| Line 30: | Line 31: | ||
*White lesions, especially irregular = suggestive of carcinoma. | *White lesions, especially irregular = suggestive of carcinoma. | ||
*White, glistening, with lobulated surface - "fish flesh" = suggestive of lymphoma. | *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> | **Subtle lobulation (~1 mm) on section suggestive of ''[[follicular lymphoma]]''.<ref>Bailey, D. 5 August 2010.</ref> | ||
=Microscopic= | =Microscopic= | ||
| Line 159: | Line 160: | ||
| mesh-like chromatin, usu. beside another one | | mesh-like chromatin, usu. beside another one | ||
| large cell, unremarkable/small nucleolus | | large cell, unremarkable/small nucleolus | ||
| CD21+, CD23+ | | CD21+, [[CD23]]+ | ||
| other ? | | other ? | ||
| image ? | | image ? | ||
| Line 189: | Line 190: | ||
*LN sampling is associated with morbidity; thus, selective LN sampling is preferred. | *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'''. | *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: | Use: | ||
*[[Sentinel lymph node sampling in breast cancer|Breast cancer]] - very common. | *[[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. | *[[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= | =See also= | ||
Latest revision as of 19:03, 15 October 2023
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. 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 article: 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.[1]
Microscopic
Lymph node architecture
Lymph node architecture (superficial to deep):[2]
- 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.
Lymph node follicles
Types of follicles:[3]
- 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 capsular aspect.
- Darker at medullary aspect.
Image:
Location and cell types
Germinal centers:[5]
- Site of B lymphocyte proliferation; follicle center cells.
- Centroblasts - usually superficial aspect. (??? deeper ???)
- Darker, larger, nucleoli.
- Centrocytes (mid germinal center).
- Cells with cleavage.
- Centrocytes (transforming to immunoblasts) - usually deeper aspect. (??? superficial ???)
- Cells with cleavage.
- Centroblasts - usually superficial aspect. (??? deeper ???)
- Tingible body macrophages - mid germinal center.
- Follicular dendritic cells.
Paracortex:[6]
- Site of T lymphocytes.
- Interdigitating dendritic cell.
Medullary cords (site of immunoglobulin synthesis):
- B lymphocytes.
- Plasma cells.
Mantle zone:
- Memory B cells.
- Usually asymmetrical; thicker, i.e. more mantle cells, at capsular aspect.[7]
Cell types
Follicular dendritic cells:[8]
- 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:[5]
- Centroblast (CB):
- Appearance:[9]
- Large cells.
- Round nucleus, dark.
- Nucleolus (nucleoli).
- Mitotically active.
- Location:
- Medullary aspect of germinal center.
- Appearance:[9]
- 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.
- Memory device: centrocytes are light (it nearly rhymes).
Image:
Cell types - table
| 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 ? |
Pathology
Main article: 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.[10]
Use:
- Breast cancer - very common.
- Malignant melanoma - first context in which SLN sampling was done.
Lymph node metastasis
Main article: Lymph node metastasis
- Cancer that has spread to a lymph node.
See also
References
- ↑ Bailey, D. 5 August 2010.
- ↑ 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.
- ↑ URL: http://www.pathpedia.com/education/eatlas/histology/lymph_node/images.aspx. Accessed on: 29 October 2012.
- ↑ 5.0 5.1 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.
- ↑ DG. 17 August 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.
- ↑ URL: http://www.healthsystem.virginia.edu/internet/hematology/HessEDD/BenignHematologicDisorders/normal-hematopoietic-cells/Secondary-lymphoid-organs-and-tissues.cfm. Accessed on: 31 January 2010.
- ↑ McMasters, KM.; Reintgen, DS.; Ross, MI.; Wong, SL.; Gershenwald, JE.; Krag, DN.; Noyes, RD.; Viar, V. et al. (Apr 2001). "Sentinel lymph node biopsy for melanoma: how many radioactive nodes should be removed?". Ann Surg Oncol 8 (3): 192-7. PMID 11314933.