Difference between revisions of "Lymph nodes"

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[[File:Lymph node metastasis from neuroendocrine tumor.jpg|thumb|Lymph node metastasis from a [[neuroendocrine tumor of the midgut]].]]
+
{{Comprehensiveness}}
 
==Gross processing==
 
==Gross processing==
In samples with tumors, slice through all included fat while palpating and looking for lymph nodes, and submit all that are found.
+
If suspected '''[[lymphoma]]''', before putting tissue in formalin, ensure that tissue is preserved in appropriate media for any special tests (usually flow cytometry). {{further|Lymphoma}}
 +
 
 +
In samples with '''tumors''', slice through all included fat while palpating and looking for lymph nodes, and submit all that are found.
 +
 
 +
For lymph nodes taken for potential '''breast cancer''' metastasis, find out and report the procurement time and the time when put in formalin.<ref group=note>The duration that a specimen has been without formalin affects mainly the reliability of estreogen and progesteron receptor testing:<br>- {{cite journal|last1=Pekmezci|first1=Melike|last2=Szpaderska|first2=Anna|last3=Osipo|first3=Clodia|last4=Erşahin|first4=Çağatay|title=The Effect of Cold Ischemia Time and/or Formalin Fixation on Estrogen Receptor, Progesterone Receptor, and Human Epidermal Growth Factor Receptor-2 Results in Breast Carcinoma|journal=Pathology Research International|volume=2012|year=2012|pages=1–7|issn=2090-8091|doi=10.1155/2012/947041}}</ref>
 +
 
 +
===Gross procedure===
 +
*'''Measure''' the dimensions. For a lymph node with minimal surrounding fatty tissue, measure the greatest dimension {{Moderate-begin}}or 3 dimensions{{Moderate-end}}. For specimens with substantial amount of fatty tissue, measure the specimen in 3 dimensions, and measure the greatest dimension seen for individual lymph nodes therein after serial sectioning.
 +
*'''Find''' as many lymph nodes as you can in a specimen. Good locations to start include the presumed lymphatic drainage directions from a tumor, as well as when following the lymphatic directions from the vascular margins of a specimen. Serially section fatty tissue into slices that are thin enough to be palpated for small ovoid resistances. If you still have trouble finding enough lymph nodes, put fatty tissue in a vinegar and acetic acid solution made for the purpose of turning lymph nodes pale/white as well as making them more firm for palpation. [[Colon tumor]]s are sometimes tattooed during endoscopy, and in such cases the tatoo ink often stains lymph nodes as well.
 +
<gallery mode=packed heights=200>
 +
File:Gross pathology of a mesenteric lymph node.jpg|Gross pathology of a mesenteric lymph node.
 +
File:Gross pathology of mesorectal lymph node after acetic acid.jpg|Lymph node in partially inked mesorectal fat after a night in '''acetic acid'''.
 +
</gallery>
 +
*'''Section''' lymph nodes if needed. Lymph nodes less than 5 mm may be submitted whole, while larger lymph nodes may be sectioned at 2-3 mm intervals.<ref>{{cite web|url=https://documents.cap.org/protocols/cp-skin-melanoma-biopsy-19-4100.pdf|title=Protocol for the Examination of Biopsy Specimens From Patients With Melanoma of the Skin|website=College of American Pathologists}} Version: Melanoma Biopsy 4.1.0.0 Protocol Posting Date: August 2019</ref>
 +
*Generally do not submit multiple sectioned lymph nodes in the same '''cassette''', to allow exact counting of the number of involved lymph nodes on microscopy. If you will nevertheless submit multiple bisected lymph nodes in the same cassette, '''[[ink]]''' each lymph node differently.
 +
[[File:Touch prep on a lymph node.jpg|thumb|220px|Making a "touch prep": Press a glass slide against the cut surface of the lymph node, apply cytologic fixative solution immediately and stain with H&E.]]
 +
*If suspected '''[[lymphoma]]''', such as an enlarged lymph node without any adjacent tumor or another almost certain cause, make a touch prep. Also, take a small fresh sample for flow cytometry:
 +
:*For '''flow cytometry''', aim for a tissue size of approximately 5 mm<sup>3</sup>. Put it in specific flow cytometry preservative medium (such as RPMI), and ensure it gets to the flow cytometry lab. If it is after normal hours and there is no one to ask to find such medium, you can put the specimen in normal sterile saline (enough to cover the tissue) in a fridge (2-8°C) until the next morning.<ref>{{cite web|url=https://lifelabs.azureedge.net/lifelabs-wp-cdn/wp-content/uploads/2018/08/SPECIMEN-INFORMATION-AND-REQUIREMENTS-FOR-FLOW-CYTOMETRY-TESTING.pdf|title=Specimen Information and Requirements for Flow Cytometry Testing|website=Lifelabs}} Doc #8218 Ver: 7.0 Current Issued: 13-Apr-2018</ref> If you receive multiple lymph nodes for flow cytometry, still only sample one (unless the referral asks for separate flow cytometry studies, or there is a given history of one lymph node having high uptake and another having low uptake on PET scanning).
 +
 
 +
===Definition of an enlarged lymph node===
 +
[[File:Long and short axis.png|120px|right]]
 +
*By size, where lymphadenopathy in adults is often defined as a short axis of one or more lymph nodes is greater than 10mm.<ref name="GaneshalingamKoh2009"/><ref name="Schmidt JúniorRodrigues2007"/> However, there is regional variation as detailed in this table:
 +
{|class="wikitable"
 +
|+Upper limit of lymph node sizes in adults
 +
|-
 +
| Generally || 10&nbsp;mm<ref name="GaneshalingamKoh2009">{{cite journal|last1=Ganeshalingam|first1=Skandadas|last2=Koh|first2=Dow-Mu|title=Nodal staging|journal=Cancer Imaging|volume=9|issue=1|pages=104–111|year=2009|issn=1470-7330|doi=10.1102/1470-7330.2009.0017|pmid=20080453|pmc=2821588}}</ref><ref name="Schmidt JúniorRodrigues2007">{{cite journal|last1=Schmidt Júnior|first1=Aurelino Fernandes|last2=Rodrigues|first2=Olavo Ribeiro|last3=Matheus|first3=Roberto Storte|last4=Kim|first4=Jorge Du Ub|last5=Jatene|first5=Fábio Biscegli|title=Distribuição, tamanho e número dos linfonodos mediastinais: definições por meio de estudo anatômico|journal=Jornal Brasileiro de Pneumologia|volume=33|issue=2|year=2007|pages=134–140|issn=1806-3713|doi=10.1590/S1806-37132007000200006|pmid=17724531|doi-access=free}}</ref>
 +
|-
 +
| Inguinal || 10<ref name=Torabi2004>{{cite journal | vauthors = Torabi M, Aquino SL, Harisinghani MG | title = Current concepts in lymph node imaging | journal = Journal of Nuclear Medicine | volume = 45 | issue = 9 | pages = 1509–18 | date = September 2004 | pmid = 15347718 }}</ref> – 20&nbsp;mm<ref>{{cite web|url=http://bestpractice.bmj.com/best-practice/monograph/838/diagnosis/step-by-step.html|title=Assessment of lymphadenopathy|website=[[BMJ Best Practice]]|accessdate=2017-03-04}} Last updated: Last updated: Feb 16, 2017</ref>
 +
|-
 +
| Pelvis || 10&nbsp;mm for ovoid lymph nodes, 8&nbsp;mm for rounded<ref name=Torabi2004/>
 +
|-
 +
!colspan=2|Neck
 +
|-
 +
| Generally (non-retropharyngeal) || 10&nbsp;mm<ref name=Torabi2004/><ref name=Saba2016>[https://books.google.com/books?id=q7v1CwAAQBAJ&pg=PA432 Page 432] in: {{cite book|title=Image Principles, Neck, and the Brain|author=Luca Saba|publisher=CRC Press|year=2016|isbn=9781482216202}}</ref>
 +
|-
 +
| Jugulodigastric lymph nodes || 11mm<ref name=Torabi2004/> or 15&nbsp;mm<ref name=Saba2016/>
 +
|-
 +
| Retropharyngeal || 8&nbsp;mm<ref name=Saba2016/>
 +
*Lateral retropharyngeal: 5&nbsp;mm<ref name=Torabi2004/>
 +
|-
 +
!colspan=2|Mediastinum
 +
|-
 +
| [[Mediastinum]], generally || 10&nbsp;mm<ref name=Torabi2004/>
 +
|-
 +
| Superior mediastinum and high paratracheal || 7mm<ref name="SharmaFidias2004"/>
 +
|-
 +
| Low paratracheal and subcarinal || 11&nbsp;mm<ref name="SharmaFidias2004">{{cite journal|last1=Sharma|first1=Amita|last2=Fidias|first2=Panos|last3=Hayman|first3=L. Anne|last4=Loomis|first4=Susanne L.|last5=Taber|first5=Katherine H.|last6=Aquino|first6=Suzanne L.|title=Patterns of Lymphadenopathy in Thoracic Malignancies|journal=RadioGraphics|volume=24|issue=2|year=2004|pages=419–434|issn=0271-5333|doi=10.1148/rg.242035075|pmid=15026591|url=https://semanticscholar.org/paper/145256a2605c552c77534f2a509227902440bf7b}}</ref>
 +
|-
 +
!colspan=2| Upper abdominal
 +
|-
 +
| Retrocrural space || 6&nbsp;mm<ref name="DorfmanAlpern1991">{{cite journal|last1=Dorfman|first1=R E|last2=Alpern|first2=M B|last3=Gross|first3=B H|last4=Sandler|first4=M A|title=Upper abdominal lymph nodes: criteria for normal size determined with CT.|journal=Radiology|volume=180|issue=2|year=1991|pages=319–322|issn=0033-8419|doi=10.1148/radiology.180.2.2068292|pmid=2068292}}</ref>
 +
|-
 +
| Paracardiac || 8&nbsp;mm<ref name="DorfmanAlpern1991"/>
 +
|-
 +
| Gastrohepatic ligament || 8&nbsp;mm<ref name="DorfmanAlpern1991"/>
 +
|-
 +
| Upper paraaortic region || 9&nbsp;mm<ref name="DorfmanAlpern1991"/>
 +
|-
 +
| Portacaval space || 10&nbsp;mm<ref name="DorfmanAlpern1991"/>
 +
|-
 +
| Porta hepatis || 7&nbsp;mm<ref name="DorfmanAlpern1991"/>
 +
|-
 +
| Lower paraaortic region || 11&nbsp;mm<ref name="DorfmanAlpern1991"/>
 +
|}
 +
 
 +
Lymphadenopathy of the '''axillary''' lymph nodes can be defined as solid nodes measuring more than 15&nbsp;mm without fatty hilum.<ref name=dahnert2011>[https://books.google.com/books?id=uYREa2bKNW8C&pg=PA559 Page 559] in: {{cite book|title=Radiology Review Manual|author=Wolfgang Dähnert|publisher=Lippincott Williams & Wilkins|year=2011|isbn=9781609139438}}</ref> Axillary lymph nodes may be normal up to 30&nbsp;mm if consisting largely of fat.<ref name=dahnert2011/>
 +
 
 +
In '''children''', a short axis of 8&nbsp;mm can be used.<ref>[https://books.google.com/books?id=nmpI1bLGCV4C&pg=PA942 Page 942] in: {{cite book|title=High Yield Imaging Gastrointestinal HIGH YIELD in Radiology|author=Richard M. Gore, Marc S. Levine|publisher=Elsevier Health Sciences|year=2010|isbn=9781455711444}}</ref> However, inguinal lymph nodes of up to 15 mm and cervical lymph nodes of up to 20 mm are generally normal in children up to age 8–12.<ref>{{cite web|website=[[Patient UK]]|url=http://patient.info/doctor/generalised-lymphadenopathy|title=Generalised Lymphadenopathy|author=Laurence Knott|accessdate=2017-03-04}} Last checked: 24 March 2014</ref>
 +
 
 +
Lymphadenopathy of more than 1.5&nbsp;cm - 2&nbsp;cm increases the risk of cancer or granulomatous disease as the cause rather than only inflammation or infection.<ref name="pmid12484692">{{cite journal | vauthors = Bazemore AW, Smucker DR | title = Lymphadenopathy and malignancy | journal = American Family Physician | volume = 66 | issue = 11 | pages = 2103–10 | date = December 2002 | pmid = 12484692  }}</ref>
 +
 
 +
===Urgency===
 +
The processing of lymph nodes is preferably rushed when the H&E stain will determine whether immunohistochemistry will be performed, especially when a lymph node is submitted together with a separate specimen that may be solved without immunostains. This rushing allows you to have the immunostained slides by a similar time as the rest of the case.<ref name="pmid12610108">{{cite journal| author=Chandler IP, Oommen R, Lawson CW| title=Invasive lobular carcinoma and cytokeratin immunohistochemistry: an audit. | journal=J Clin Pathol | year= 2003 | volume= 56 | issue= 3 | pages= 240 | pmid=12610108 | doi=10.1136/jcp.56.3.240 | pmc=1769908 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=12610108  }} </ref> Examples of cases that are preferably rushed for such reasons include those that may be stained by CK AE1/AE3 in order to visualize otherwise occult lymph node involvement if you don't see any involvement on the H&E stain, mainly in cases when one or more sentinel lymph nodes are submitted together with any of the following:
 +
*A [[breast biopsy or excision]] of a suspected or previously confirmed [[invasive lobular carcinoma]] (but not necessarily invasive carcinoma with lobular features)
 +
*A [[uterus]] specimen of a suspected or previously confirmed [[endometrial cancer]].
 +
Rushing is not necessary for non-sentinel lymph nodes.
 +
 
 +
===Gross report===
 +
;Individual lymph node, example:
 +
{{Report-begin}} __ fragment(s) of soft pink-tan tissue, measuring __ cm in greatest dimension {{Moderate-begin}}or __ x __ x __{{Moderate-begin}}.{{Report-end}}
 +
 
 +
;Multiple lymph nodes
 +
{{Report-begin|fresh=yes}} 2 irregular fragments of yellow-tan fatty and fibrous soft tissue measuring __ and ___ cm in greatest dimension.  Within the adipose tissue are multiple tan-brown lymph nodes measuring up to __ cm in greatest dimension. The cut surfaces display no gross lesions. The lymph nodes are entirely submitted for microscopic examination {{Moderate-begin}}in 10 cassettes{{Moderate-end}}.<br>KEY TO SECTIONS:
 +
*A1–A3– one lymph node, serially section
 +
*A4-A5– one lymph node, serially sectioned
 +
*A6– one lymph node, bisected
 +
*A7– one lymph node, bisected
 +
*A8– two lymph nodes, each bisected, differentially inked
 +
*A9– one lymph node, bisected
 +
*A10– multiple lymph nodes.
 +
|}
 +
 
 +
;Additional information
 +
*If potential breast cancer metastasis: The specimen was procured at __ AM/PM on (date), 2020. The specimen was placed in formalin at __ AM/PM on (date), 2020.
 +
*If '''[[lymphoma]]''' workup: A touch prep is made, and a minor part of the specimen is submitted for flow cytometry. The remainder of the specimen is submitted for microscopic examination in one cassette.
  
 
==Microscopic examination==
 
==Microscopic examination==
Look for whatever pathology is indicated by the referral, or findings in other submitted specimens. The main target conditions are:
+
===Defining a lymph node===
*'''Metastasis''', which usually looks similar to the primary tumor (neuroendocrine tumor in picture at right).
+
For counting lymph nodes, each should have a discernible capsule around lymphoid cells. Also count larger free-standing lymphoid aggregates. However, the definition of what constitutes a lymph node is largely subjective.<ref>{{cite journal| author=Parkash V, Bifulco C, Feinn R, Concato J, Jain D| title=To count and how to count, that is the question: interobserver and intraobserver variability among pathologists in lymph node counting. | journal=Am J Clin Pathol | year= 2010 | volume= 134 | issue= 1 | pages= 42-9 | pmid=20551265 | doi=10.1309/AJCPO92DZMUCGEUF | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=20551265  }}</ref> Also strive to keep a consistency with the gross description. In addition, any cancer involvement is in itself a relative indication of being a lymph node.
*'''Reactive''' lymphadenopathy, by inflammation in an adjacent area, or systemic.
 
  
===Reactive lymphadenopathy===
+
===General screening===
Follicular hyperplasia is the most common pattern of reactive lymphadenopathy.<ref name="WeissO'Malley2013">{{cite journal|last1=Weiss|first1=Lawrence M|last2=O'Malley|first2=Dennis|title=Benign lymphadenopathies|journal=Modern Pathology|volume=26|issue=S1|year=2013|pages=S88–S96|issn=0893-3952|doi=10.1038/modpathol.2012.176}}</ref> It is usually associated with varying degrees of paracortical and/or sinus hyperplasia.
+
Look for:
 +
*Whatever pathology is '''indicated''' by the referral, or findings in other submitted specimens.
 +
:*'''Enlargement''', as preferably measured during grossing, but can possibly be made on the microscopy slide. If present, see separate section below.
 +
<gallery mode=packed heights=200>
 +
File:Microscopic lymph node screening.jpg|'''Metastases''': generally first look around the edges with intermediate magnification, and low mag in the middle, since cancer metastases usually occur at edges (as in this case). For suspected urothelial cancers, however, look closely throughout the node, as they have a tendency to show up anywhere in lymph nodes.
 +
File:Lymph node metastasis from neuroendocrine tumor.jpg|Lymph node '''metastasis''' from a [[neuroendocrine tumor of the midgut]]. Metastates generally look similar to its primary tumor.
 +
File:Granuloma 20x.jpg|'''Granulomas''' (non-necrotizing granuloma pictured). If seen generally perform staining for acid-fast bacilli, and GMS stain for fungi.
 +
</gallery>
 +
 
 +
===Microscopy of enlarged lymph nodes===
 +
Look at any '''other slides''' for the same case first, in order to find any pathology that may be reflected in in the lymph nodes as well, mainly cancer metastasis or '''[[reactive lymph node]]s''' from inflammation.
 +
 
 +
Look primarily at the overall '''architecture''', with main findings being:
 
<gallery mode=packed heights=220>
 
<gallery mode=packed heights=220>
File:Histopathology of reactive follicular hyperplasia.jpg|thumb|Histopathology of reactive follicular hyperplasia
+
File:Histopathology of reactive follicular hyperplasia.jpg|'''Follicular hyperplasia''': Indicates mainly ''follicular hyperplasia of a '''[[reactive lymph node]]''''' (pictured) or ''follicular lymphoma''. {{Further|Follicular hyperplasia|linebreak=no}}
 +
File:Sinus histiocytosis (intermediate magnification).jpg|'''Dilated sinuses'''. The most cellular expansion is '''sinus histiocytosis''' (pictured). If it appears as such, look for a ''signet ring appearance'', which may be a [[signet ring carcinoma]] or [[melanoma]]. If unsure, use immunostains for CD68, cytokeratin, S100 and mucin.<ref name="EganJaffe2018">{{cite journal|last1=Egan|first1=Caoimhe|last2=Jaffe|first2=Elaine S.|title=Non-neoplastic histiocytic and dendritic cell disorders in lymph nodes|journal=Seminars in Diagnostic Pathology|volume=35|issue=1|year=2018|pages=20–33|issn=07402570|doi=10.1053/j.semdp.2017.11.002}}</ref>
 
</gallery>
 
</gallery>
It usually has varying amount of paracortical and/or sinus hyperplasia.<ref name="WeissO'Malley2013"/> Older age, increased follicular density (especially back-to-back arrangement) and areas of diffuse nodal effacement leads to a suspicion of '''[[follicular lymphoma]]'''.<ref name="WeissO'Malley2013"/> {{Further|Follicular lymphoma versus reactive follicular hyperplasia}}
+
*'''Paracortical hyperplasia''': Paracortical hyperplasia of a '''[[reactive lymph node]]''' shows expansion of paracortical areas by a mixed infiltrate, often having a mottled appearance, and it usually has a concomitant reactive follicular hyperplasia.<ref name="WeissO'Malley2013">{{cite journal|last1=Weiss|first1=Lawrence M|last2=O'Malley|first2=Dennis|title=Benign lymphadenopathies|journal=Modern Pathology|volume=26|issue=S1|year=2013|pages=S88–S96|issn=0893-3952|doi=10.1038/modpathol.2012.176}}</ref> A [[T-cell lymphoma]] should be suspected if there is obliteration or marked diminution of the B-cell cortical region, or highly irregular or hyperchromatic nuclei.<ref name="WeissO'Malley2013"/>
 +
*'''Unspecific hyperplasia''': An unspecific pattern of lymph node enlargement, without atypical cells, in the lymphatic drainage direction from an inflamed area, may simply be diagnosed as "benign '''[[reactive lymph node]]'''".
 +
 
 +
===Workup of cancerous lymph nodes===
 +
If cancer is detected in a lymph node:
 +
*Attempt to specify a specific cancer ''diagnosis'''. If the patient has a known carcinoma or sarcoma etc, it is generally enough to confirm that it is consistent with a metastasis thereof.
 +
*Measure the '''size''' of involvement.
 +
*Look for '''extranodal extension'''.
 +
 
 +
==Reporting==
 +
A non-involved lymph node in a patient with cancer can be reported for example as:
 +
{|class=wikitable
 +
| Sentinel lymph node #1, left axilla, {{Moderate-begin}}excision{{Moderate-end}}:<br>One benign lymph node{{Comprehensive-begin}}, negative for malignancy (0/1){{Comprehensive-end}}.
 +
|}
  
===Common findings===
+
Cancerous lymph nodes with patients with known consistent cancer primary can be reported as metastatic,, such as:
<gallery mode=packed heights=210>
+
{|class=wikitable
File:Histopathology of a reactive lymph node in cholecystitis.jpg|Reactive lymph node
+
| Sentinel lymph node #2, left axilla, {{Moderate-begin}}excision{{Moderate-end}}:<br>Macrometastatic carcinoma involving one of one (1/1) lymph node.<br>Metastatic carcinoma measures 0.4 cm in greatest dimension.<br>{{Moderate-begin}}Negative for extranodal extension{{Moderate-end}}.
</gallery>
+
|}
 
{{Bottom}}
 
{{Bottom}}

Latest revision as of 18:28, 1 September 2022

Author: Mikael Häggström [note 1]

Comprehensiveness

On this resource, the following formatting is used for comprehensiveness:

  • Minimal depth
  • (Moderate depth)
  • ((Comprehensive))

Gross processing

If suspected lymphoma, before putting tissue in formalin, ensure that tissue is preserved in appropriate media for any special tests (usually flow cytometry). Further information: Lymphoma

In samples with tumors, slice through all included fat while palpating and looking for lymph nodes, and submit all that are found.

For lymph nodes taken for potential breast cancer metastasis, find out and report the procurement time and the time when put in formalin.[note 2]

Gross procedure

  • Measure the dimensions. For a lymph node with minimal surrounding fatty tissue, measure the greatest dimension (or 3 dimensions). For specimens with substantial amount of fatty tissue, measure the specimen in 3 dimensions, and measure the greatest dimension seen for individual lymph nodes therein after serial sectioning.
  • Find as many lymph nodes as you can in a specimen. Good locations to start include the presumed lymphatic drainage directions from a tumor, as well as when following the lymphatic directions from the vascular margins of a specimen. Serially section fatty tissue into slices that are thin enough to be palpated for small ovoid resistances. If you still have trouble finding enough lymph nodes, put fatty tissue in a vinegar and acetic acid solution made for the purpose of turning lymph nodes pale/white as well as making them more firm for palpation. Colon tumors are sometimes tattooed during endoscopy, and in such cases the tatoo ink often stains lymph nodes as well.
  • Section lymph nodes if needed. Lymph nodes less than 5 mm may be submitted whole, while larger lymph nodes may be sectioned at 2-3 mm intervals.[1]
  • Generally do not submit multiple sectioned lymph nodes in the same cassette, to allow exact counting of the number of involved lymph nodes on microscopy. If you will nevertheless submit multiple bisected lymph nodes in the same cassette, ink each lymph node differently.
Making a "touch prep": Press a glass slide against the cut surface of the lymph node, apply cytologic fixative solution immediately and stain with H&E.
  • If suspected lymphoma, such as an enlarged lymph node without any adjacent tumor or another almost certain cause, make a touch prep. Also, take a small fresh sample for flow cytometry:
  • For flow cytometry, aim for a tissue size of approximately 5 mm3. Put it in specific flow cytometry preservative medium (such as RPMI), and ensure it gets to the flow cytometry lab. If it is after normal hours and there is no one to ask to find such medium, you can put the specimen in normal sterile saline (enough to cover the tissue) in a fridge (2-8°C) until the next morning.[2] If you receive multiple lymph nodes for flow cytometry, still only sample one (unless the referral asks for separate flow cytometry studies, or there is a given history of one lymph node having high uptake and another having low uptake on PET scanning).

Definition of an enlarged lymph node

Long and short axis.png
  • By size, where lymphadenopathy in adults is often defined as a short axis of one or more lymph nodes is greater than 10mm.[3][4] However, there is regional variation as detailed in this table:
Upper limit of lymph node sizes in adults
Generally 10 mm[3][4]
Inguinal 10[5] – 20 mm[6]
Pelvis 10 mm for ovoid lymph nodes, 8 mm for rounded[5]
Neck
Generally (non-retropharyngeal) 10 mm[5][7]
Jugulodigastric lymph nodes 11mm[5] or 15 mm[7]
Retropharyngeal 8 mm[7]
  • Lateral retropharyngeal: 5 mm[5]
Mediastinum
Mediastinum, generally 10 mm[5]
Superior mediastinum and high paratracheal 7mm[8]
Low paratracheal and subcarinal 11 mm[8]
Upper abdominal
Retrocrural space 6 mm[9]
Paracardiac 8 mm[9]
Gastrohepatic ligament 8 mm[9]
Upper paraaortic region 9 mm[9]
Portacaval space 10 mm[9]
Porta hepatis 7 mm[9]
Lower paraaortic region 11 mm[9]

Lymphadenopathy of the axillary lymph nodes can be defined as solid nodes measuring more than 15 mm without fatty hilum.[10] Axillary lymph nodes may be normal up to 30 mm if consisting largely of fat.[10]

In children, a short axis of 8 mm can be used.[11] However, inguinal lymph nodes of up to 15 mm and cervical lymph nodes of up to 20 mm are generally normal in children up to age 8–12.[12]

Lymphadenopathy of more than 1.5 cm - 2 cm increases the risk of cancer or granulomatous disease as the cause rather than only inflammation or infection.[13]

Urgency

The processing of lymph nodes is preferably rushed when the H&E stain will determine whether immunohistochemistry will be performed, especially when a lymph node is submitted together with a separate specimen that may be solved without immunostains. This rushing allows you to have the immunostained slides by a similar time as the rest of the case.[14] Examples of cases that are preferably rushed for such reasons include those that may be stained by CK AE1/AE3 in order to visualize otherwise occult lymph node involvement if you don't see any involvement on the H&E stain, mainly in cases when one or more sentinel lymph nodes are submitted together with any of the following:

Rushing is not necessary for non-sentinel lymph nodes.

Gross report

Individual lymph node, example
((A. Labeled - ___. The specimen is received in formalin and consists of)) __ fragment(s) of soft pink-tan tissue, measuring __ cm in greatest dimension (or __ x __ x __(. (Representative sections are submitted for microscopic examination in __ cassettes.)
Multiple lymph nodes
((A. Labeled - ___. The specimen is received fresh and consists of)) 2 irregular fragments of yellow-tan fatty and fibrous soft tissue measuring __ and ___ cm in greatest dimension. Within the adipose tissue are multiple tan-brown lymph nodes measuring up to __ cm in greatest dimension. The cut surfaces display no gross lesions. The lymph nodes are entirely submitted for microscopic examination (in 10 cassettes).
KEY TO SECTIONS:
  • A1–A3– one lymph node, serially section
  • A4-A5– one lymph node, serially sectioned
  • A6– one lymph node, bisected
  • A7– one lymph node, bisected
  • A8– two lymph nodes, each bisected, differentially inked
  • A9– one lymph node, bisected
  • A10– multiple lymph nodes.
Additional information
  • If potential breast cancer metastasis: The specimen was procured at __ AM/PM on (date), 2020. The specimen was placed in formalin at __ AM/PM on (date), 2020.
  • If lymphoma workup: A touch prep is made, and a minor part of the specimen is submitted for flow cytometry. The remainder of the specimen is submitted for microscopic examination in one cassette.

Microscopic examination

Defining a lymph node

For counting lymph nodes, each should have a discernible capsule around lymphoid cells. Also count larger free-standing lymphoid aggregates. However, the definition of what constitutes a lymph node is largely subjective.[15] Also strive to keep a consistency with the gross description. In addition, any cancer involvement is in itself a relative indication of being a lymph node.

General screening

Look for:

  • Whatever pathology is indicated by the referral, or findings in other submitted specimens.
  • Enlargement, as preferably measured during grossing, but can possibly be made on the microscopy slide. If present, see separate section below.

Microscopy of enlarged lymph nodes

Look at any other slides for the same case first, in order to find any pathology that may be reflected in in the lymph nodes as well, mainly cancer metastasis or reactive lymph nodes from inflammation.

Look primarily at the overall architecture, with main findings being:

  • Paracortical hyperplasia: Paracortical hyperplasia of a reactive lymph node shows expansion of paracortical areas by a mixed infiltrate, often having a mottled appearance, and it usually has a concomitant reactive follicular hyperplasia.[17] A T-cell lymphoma should be suspected if there is obliteration or marked diminution of the B-cell cortical region, or highly irregular or hyperchromatic nuclei.[17]
  • Unspecific hyperplasia: An unspecific pattern of lymph node enlargement, without atypical cells, in the lymphatic drainage direction from an inflamed area, may simply be diagnosed as "benign reactive lymph node".

Workup of cancerous lymph nodes

If cancer is detected in a lymph node:

  • Attempt to specify a specific cancer diagnosis'. If the patient has a known carcinoma or sarcoma etc, it is generally enough to confirm that it is consistent with a metastasis thereof.
  • Measure the size of involvement.
  • Look for extranodal extension.

Reporting

A non-involved lymph node in a patient with cancer can be reported for example as:

Sentinel lymph node #1, left axilla, (excision):
One benign lymph node((, negative for malignancy (0/1))).

Cancerous lymph nodes with patients with known consistent cancer primary can be reported as metastatic,, such as:

Sentinel lymph node #2, left axilla, (excision):
Macrometastatic carcinoma involving one of one (1/1) lymph node.
Metastatic carcinoma measures 0.4 cm in greatest dimension.
(Negative for extranodal extension).

Notes

  1. For a full list of contributors, see article history. Creators of images are attributed at the image description pages, seen by clicking on the images. See Patholines:Authorship for details.
  2. The duration that a specimen has been without formalin affects mainly the reliability of estreogen and progesteron receptor testing:
    - Pekmezci, Melike; Szpaderska, Anna; Osipo, Clodia; Erşahin, Çağatay (2012). "The Effect of Cold Ischemia Time and/or Formalin Fixation on Estrogen Receptor, Progesterone Receptor, and Human Epidermal Growth Factor Receptor-2 Results in Breast Carcinoma ". Pathology Research International 2012: 1–7. doi:10.1155/2012/947041. ISSN 2090-8091. 

Main page

References

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  2. . Specimen Information and Requirements for Flow Cytometry Testing. Lifelabs. Doc #8218 Ver: 7.0 Current Issued: 13-Apr-2018
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  10. 10.0 10.1 Page 559 in: Wolfgang Dähnert (2011). Radiology Review Manual . Lippincott Williams & Wilkins. ISBN 9781609139438. 
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  14. Chandler IP, Oommen R, Lawson CW (2003). "Invasive lobular carcinoma and cytokeratin immunohistochemistry: an audit. ". J Clin Pathol 56 (3): 240. doi:10.1136/jcp.56.3.240. PMID 12610108. PMC: 1769908. Archived from the original. . 
  15. Parkash V, Bifulco C, Feinn R, Concato J, Jain D (2010). "To count and how to count, that is the question: interobserver and intraobserver variability among pathologists in lymph node counting. ". Am J Clin Pathol 134 (1): 42-9. doi:10.1309/AJCPO92DZMUCGEUF. PMID 20551265. Archived from the original. . 
  16. Egan, Caoimhe; Jaffe, Elaine S. (2018). "Non-neoplastic histiocytic and dendritic cell disorders in lymph nodes ". Seminars in Diagnostic Pathology 35 (1): 20–33. doi:10.1053/j.semdp.2017.11.002. ISSN 07402570. 
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Image sources