Lymph nodes - Revision history

Mikael Häggström: Moved to talk page

2026-01-06T21:53:01Z

Moved to talk page

@@ Line 23: / Line 23: @@
 *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).
 ===Urgency===

Mikael Häggström: /* Gross procedure */ Touch prep

2022-09-01T22:28:14Z

Gross procedure: Touch prep

← Older revision		Revision as of 18:28, 1 September 2022
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	*'''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>		*'''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.		*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.
	*If suspected '''[[lymphoma]]''', such as an enlarged lymph node without any adjacent tumor or another almost certain cause, make 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)~~. Also, take a small fresh sample for flow cytometry:		[[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).		:*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).

Mikael Häggström: Integrated

2022-06-22T16:17:13Z

Integrated

← Older revision		Revision as of 12:17, 22 June 2022
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	:*'''Enlargement''', as preferably measured during grossing, but can possibly be made on the microscopy slide. If present, see separate section below.		:*'''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>		<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).~~<ref group=notes>Urothelial~~ cancers, however, have a tendency to show up anywhere in lymph nodes.~~</ref>~~		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: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.		File:Granuloma 20x.jpg\|'''Granulomas''' (non-necrotizing granuloma pictured). If seen generally perform staining for acid-fast bacilli, and GMS stain for fungi.

Mikael Häggström: /* Defining a lymph node */ Integrated

2022-06-22T16:12:34Z

Defining a lymph node: Integrated

← Older revision		Revision as of 12:12, 22 June 2022
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	==Microscopic examination==		==Microscopic examination==
	===Defining a lymph node===		===Defining a lymph node===
	For counting lymph nodes, each should have a discernible capsule around lymphoid cells. Also count larger free-standing lymphoid aggregates.~~<ref group=notes>~~However, the definition of what constitutes a lymph node is largely subjective.<br> -{{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.		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.

	===General screening===		===General screening===

Mikael Häggström: /* Gross processing */ note

2022-06-22T13:00:34Z

Gross processing: note

← Older revision		Revision as of 09:00, 22 June 2022
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	In samples with '''tumors''', slice through all included fat while palpating and looking for lymph nodes, and submit all that are found.		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=~~notes~~>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>		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===		===Gross procedure===

Mikael Häggström: Not necessary for non-sentinel

2022-03-01T16:00:32Z

Not necessary for non-sentinel

← Older revision		Revision as of 12:00, 1 March 2022
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	===Urgency===		===Urgency===
	The processing of lymph nodes ~~may be~~ 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 ~~may be~~ 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:		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 [[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]].		*A [[uterus]] specimen of a suspected or previously confirmed [[endometrial cancer]].
			Rushing is not necessary for non-sentinel lymph nodes.

	===Gross report===		===Gross report===

Mikael Häggström: /* Gross processing */ +Urgency

2022-02-24T15:18:18Z

Gross processing: +Urgency

← Older revision		Revision as of 11:18, 24 February 2022
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	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.<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>		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.<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 may be 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 may be 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]].

	===Gross report===		===Gross report===

Mikael Häggström: /* General screening */ +Workup

2021-11-22T19:15:08Z

General screening: +Workup

← Older revision		Revision as of 15:15, 22 November 2021
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	Look for:		Look for:
	*Whatever pathology is '''indicated''' by the referral, or findings in other submitted specimens.		*Whatever pathology is '''indicated''' by the referral, or findings in other submitted specimens.
	*General '''screening''':		:*'''Enlargement''', as preferably measured during grossing, but can possibly be made on the microscopy slide. If present, see separate section below.
	~~:*Any '''metastasis''', which usually looks similar to the primary tumor (neuroendocrine tumor in picture at right).~~
	:*'''Enlargement''', as preferably measured during grossing, but can possibly be made on the microscopy slide. If present, see section below:

	<gallery mode=packed heights=200>		<gallery mode=packed heights=200>
	File:Microscopic lymph node screening.jpg\|~~When looking for~~ '''~~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).<ref group=notes>Urothelial cancers, however, have a tendency to show up anywhere in lymph nodes.</ref>		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).<ref group=notes>Urothelial cancers, however, have a tendency to show up anywhere in lymph nodes.</ref>
	File:Lymph node metastasis from neuroendocrine tumor.jpg\|Lymph node metastasis from a [[neuroendocrine tumor of the midgut]].		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>		</gallery>

Mikael Häggström: /* Gross procedure */ °

2021-11-22T00:43:13Z

Gross procedure: °

← Older revision		Revision as of 20:43, 21 November 2021
Line 21:		Line 21:
	*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.		*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.
	*If suspected '''[[lymphoma]]''', such as an enlarged lymph node without any adjacent tumor or another almost certain cause, make 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). Also, take a small fresh sample for flow cytometry:		*If suspected '''[[lymphoma]]''', such as an enlarged lymph node without any adjacent tumor or another almost certain cause, make 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). 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<sup>o</sup>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).		:*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===		===Definition of an enlarged lymph node===

Mikael Häggström: /* Gross procedure */ +Multiple

2021-11-22T00:41:56Z

Gross procedure: +Multiple

← Older revision		Revision as of 20:41, 21 November 2021
Line 21:		Line 21:
	*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.		*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.
	*If suspected '''[[lymphoma]]''', such as an enlarged lymph node without any adjacent tumor or another almost certain cause, make 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). Also, take a small fresh sample for flow cytometry:		*If suspected '''[[lymphoma]]''', such as an enlarged lymph node without any adjacent tumor or another almost certain cause, make 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). 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<sup>o</sup>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>		:*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<sup>o</sup>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===		===Definition of an enlarged lymph node===