Pathology Associates Of Lexington, P.A.
Pathology Associates Of Lexington, P.A.
Pathology Associates Of Lexington, P.A.
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        Lymph Node Dissection

[disclaimer] This degree of effort on all node dissections is controversial nationally & internationally, and none of the techniques are FDA approved or rejected. We determined in about 1980 that use of an inexpensive special fixative would aid in both the visual and palpable detection of lymph nodes even as small as 1-2 mm. in diameter. Hartmann's fixative is an alcoholic formalin solution which also contains acetic acid. It is a rapidly penetrating fixative which keeps fat soft and firms up almost all other tissues. By palpation, one can more readily feel the rounded to oval lymph nodes which fix distinctly firmer. The solution turns DNA-rich foci (nodes) white on cut surface, nodes often containing excessive amounts of DNA-rich lymphocytes.


PAs have given us a huge advantage! As our pathology group enlarged, it became apparent that optimal performance of a lymph node dissection appealed far more strongly to the pride-of-performance of a really good PA (pathologist assistant) than to the average pathologist. It is a thing of high importance to a properly motivated PA, while it is drudgery at the end of a mentally intense day for the average pathologist. Our PAs do node dissections on most of the breast, melanoma, and colon cancer cases. And, IHC has been a huge help in detecting positive nodes, especially in cancers such is invasive lobular breast cancer...which tends to invade nodes as single cells.

Does the throughness of histological sectioning of recovered nodes make any difference? When I began practicing in 1975, little or no effort was made to recover small nodes (the unofficial cut-off maybe being less than 0.5 cm). And large nodes were typically sampled (maybe a representative block for a 1-2cm node). I remember numerous "poster presentations" at national meetings assuring us that small mets weren't of any definite prognostic consequence. But, in intervening years, oncologic treatment decisions have become much more complex. As of May 2001, all outcomes data was based on "ordinary processing". So, in 1978, a report came out which seemed to explain why 25% of node negative breast cancers behaved like node positive: stepcut sectioning through archived node blocks (which were quite likely non-thorough dissections from many years prior) converted about 25% of node negative cases to node positive...the mets were in the parafin blocks, undetected2. Those "negative" cases were NOT NEGATIVE!

OUR INTENSE PROCESS: We intensify the gross dissection by using Hartmann's acetic alcohol as an initial "node revealing" fixative. We have most dissections performed by PAs who clearly understand the importance of the node dissection who are un-distracted by the pressure to sign out the daily case load (though they have their pressure to keep the daily grossing moving on time). Except for bulky, obviously positive nodes, all of every node is submitted for histology. For breast and melanoma cases, we agar pre-embed the nodes with depth sticks to discipline the sectioning through the completely submitted node slices by the histotechnologist. The depth sticks are composed of colored agar of 3 colors, each color zone about 1.5-2.0 mm thick. The sectioning is with stepcuts producing at least 4 slides per block: first in first color, second in middle color...also at least one IHC @ this level, 3rd in the 3rd color and 4th nearly thru that 3rd color.

Does the number of nodes...the thoroughness of node dissection make any difference? Feb. 2002 issue of American Journal of Surgical Pathology reports a massive study proving that a maximal intensity of effort to recover all nodes actually resected from the colorectal cancer (CRC) patient is of high prognostic value ( 26:179-189, 2002) include 1 and 2 mm nodes! We have an even more intense protocol using agar depth sticks for node dissections in breast cancer, melanoma, and Merkel cell cancer cases (an intensity not needed in CRC), see above.

Does the size & location of mets in a node make any difference? The finding of malignant cells in nodes means that the node is not negative. If it has a pattern of parenchymal invasion in the node, it is highly unlikely to be a cancer-cell-cluster caught in "mechaninical transport". And, if it is found in the efferent (exiting) aspect of the node, there is high risk that the next node in the chain is positive, too. Yet, even in early 2017, there is reluctance in the AJCC TNM system to regard nodes with individual tumor cells as "positive nodes". The TRUTH is that such nodes are not negative.

Does the character of the malignancy increase the probability of positive nodes at time of diagnosis? Yes! Invasive micropapillary adenocarcinomas have an incredible tendency toward early node metastasis. Thick and/or high-mitotic-rate melanomas are more likely to have metastasized at the time of diagnosis. In colorectal cancer, as to H&E features, conspicuous Crohn's-like lymphoid reaction at the invasive front, lymphatic invasion, and conspicuous neutrophile infiltration of the malignant infiltration at the invasive front herald a likelihood that one should find one or more positive nodes1 (remember to look fo tiny nodes that are immediately extramuscular). Here is our intense protocol for some cancers, see above.

As an example of how well this has worked in our practice, I began the below file of examples 9/2001. It will contain some cases from the past and may be added to over time (but not by any means a complete tabulation!). Note the frequency of findings of one small positive lymph node. I promise you that no one should assume that our intensity of service and full-court press is duplicated in all pathology labs! In fact, when we first began, we were teased by other groups for being so compulsive (intense lymph node protocol used on breast & melanoma cases).

Case number Cancer organ Comments
LMC-96-2632 (CR)
54 y/o male; one of 
51 y/o male; one of 13 small nodes has a 1 mm. met.
51 y/o female; one of 13 nodes positive
38 y/o male; one 5mm. node of 23 nodes is positive
60 y/o male 1 of 72 is pos.
43 y/o male 29 neg.
breast lumpect. & ax. sample, 7 nodes
46 y/o female; one node has tiny tumor clusters afferent capsular vessel
86 y/o female; one (5 mm.) node of 17 is positive
54 y/o female; one of 23 nodes barely positive by direct extension
62 y/o female; 1 of 32
skin melanoma, arm
46 y/o female; .85 Breslow, Clark IV; 1 of 3 HMB45 "trace"+ but B9 nuclei...monocytic cells...not melanoma!
71 y/o anemia w/u finds small, thin rectal ca.; no nodes found after twice exam of tissue
breast, SLN plus 7
56 y/o female; both 1.25 cm SLNs each had an H&E micromet., 1 & .75 mm. respectively, the largest seen on FS
79 y/o male; 1 of 16 nodes has a 1.5 mm met in 8 mm. node
59 y/o male; 1 of 54 has a 6 mm. met. in a 10 mm. (prob. SLN) node
73 y/o male; 1 (?) 0f 32...(a 2mm. mucin pool in 1 node)
56 y/o female; 1 of 11 nodes, has a 1 mm. met.
42 y/o female; 7 ca. masses; 1 of 11 nodes with multiple tiny IHC pos. invasive foci
85 y/o female; 7x4 mm. met. in 1 of 4 nodes
77 y/o female; 1 of 22 nodes
45 y/o female; 1 of 5 has a 1.5 cm macromet.
57 y/o female; 1 mm. met in 3.5 mm node...of25 nodes
58 y/o female; 1 of 7 has a 7 mm met in a 1.3 cm node
62 y/o male; 2 of 23, one is 2.5 mm node directly adjacent to tumor periphery & directly invaded; of the other 22, half of a 4.5 mm node contains a met. (other half neg.)
76 y/o male; 1 of 31 small nodes...a 4mm node 80% replaced
43 y/0 female; 1 of 126 nodes...a 2mm met. in a 4mm node.
50 y/o male; 1 of 58 nodes...a 1mm met. in a 4mm node, the original polyp BX having removed the only focus of at least intramucosal cancer in a cecal tubular adenoma.
60 y/o female; 1 of 3 sentinel nodes reveals an in-transit, intracapsular 0.2 mm node met seen by IHC and H&E in just a couple of slide frames in the whole study series. NOT a negative node.


  1. Akishima-Fukasawa Y, et. al., Histopathological predictors of regional lymph node metastasis at the invasive front in early colorectal cancer, Histopathology 59(3):470-481, September, 2011.
  2. Edwin R. Fisher MD, S. Swamidoss MD, C. H. Lee MD, Howard Rockette PhD, Carol Redmond SCD, Bernard Fisher MD, "Detection and significance of occult axillary node metastases in patients with invasive breast cancer." Cancer 1978; 42(4):2025-31.
  3. This page is posted on YouTube (search YouTube using the search term "agar pre-embedding").

(posted Sept. 2001, latest update 9 February 2017)

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