On this resource, the following formatting is used for comprehensiveness:
- Minimal depth
- (Moderate depth)
If suspected lymphoma, before putting tissue in formalin, ensure that tissue is preserved in appropriate media for any special tests (usually cytometry).
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.[notes 2]
- 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.
- 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.
Definition of an enlarged lymph node
- By size, where lymphadenopathy in adults is often defined as a short axis of one or more lymph nodes is greater than 10mm. However, there is regional variation as detailed in this table:
|Inguinal||10 – 20 mm|
|Pelvis||10 mm for ovoid lymph nodes, 8 mm for rounded|
|Generally (non-retropharyngeal)||10 mm|
|Jugulodigastric lymph nodes||11mm or 15 mm|
|Mediastinum, generally||10 mm|
|Superior mediastinum and high paratracheal||7mm|
|Low paratracheal and subcarinal||11 mm|
|Retrocrural space||6 mm|
|Gastrohepatic ligament||8 mm|
|Upper paraaortic region||9 mm|
|Portacaval space||10 mm|
|Porta hepatis||7 mm|
|Lower paraaortic region||11 mm|
Lymphadenopathy of the axillary lymph nodes can be defined as solid nodes measuring more than 15 mm without fatty hilum. Axillary lymph nodes may be normal up to 30 mm if consisting largely of fat.
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.
- 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:
- 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.
Defining a lymph node
For counting lymph nodes, each should have a discernible capsule around lymphoid cells. Also count larger free-standing lymphoid aggregates.[notes 3] A defining question is: If a known cancer was found in there, would it be classified as a lymph node metastasis, lymphovascular invasion or for example tumor budding?
- Whatever pathology is indicated by the referral, or findings in other submitted specimens.
- General screening:
- 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:
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).[notes 4]
Lymph node metastasis from a neuroendocrine tumor of the midgut.
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. 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.
- 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".
- 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.
- 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.
- However, the definition of what constitutes a lymph node is largely subjective.
-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. .
- Urothelial cancers, however, have a tendency to show up anywhere in lymph nodes.
- . Protocol for the Examination of Biopsy Specimens From Patients With Melanoma of the Skin. College of American Pathologists. Version: Melanoma Biopsy 22.214.171.124 Protocol Posting Date: August 2019
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- Schmidt Júnior, Aurelino Fernandes; Rodrigues, Olavo Ribeiro; Matheus, Roberto Storte; Kim, Jorge Du Ub; Jatene, Fábio Biscegli (2007). "Distribuição, tamanho e número dos linfonodos mediastinais: definições por meio de estudo anatômico ". Jornal Brasileiro de Pneumologia 33 (2): 134–140. doi:10.1590/S1806-37132007000200006. ISSN 1806-3713. PMID 17724531.
- "Current concepts in lymph node imaging ". Journal of Nuclear Medicine 45 (9): 1509–18. September 2004. PMID 15347718.
- . Assessment of lymphadenopathy. BMJ Best Practice. Retrieved on 2017-03-04. Last updated: Last updated: Feb 16, 2017
- Page 432 in: Luca Saba (2016). Image Principles, Neck, and the Brain . CRC Press. ISBN 9781482216202.
- Sharma, Amita; Fidias, Panos; Hayman, L. Anne; Loomis, Susanne L.; Taber, Katherine H.; Aquino, Suzanne L. (2004). "Patterns of Lymphadenopathy in Thoracic Malignancies ". RadioGraphics 24 (2): 419–434. doi:10.1148/rg.242035075. ISSN 0271-5333. PMID 15026591. Archived from the original. .
- Dorfman, R E; Alpern, M B; Gross, B H; Sandler, M A (1991). "Upper abdominal lymph nodes: criteria for normal size determined with CT. ". Radiology 180 (2): 319–322. doi:10.1148/radiology.180.2.2068292. ISSN 0033-8419. PMID 2068292.
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- Laurence Knott. Generalised Lymphadenopathy. Patient UK. Retrieved on 2017-03-04. Last checked: 24 March 2014
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- 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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