A pathologist's guide to becoming more comfortable with lymph node cytology

Cytology is an important part of day-to-day life in practice, but it can be considered a challenge, plus some veterinary schools might not have taught this to students adequately. Because of this, some general practitioners may not feel confident in their skills when it comes to cytology.

During her lecture, "Lymph Node Cytology for General Practitioners" at the 2025 Fetch Nashville conference in Nashville, Tennessee, Kate Baker, DVM, MS, DACVP (Clinical Pathology), founder and chief pathologist at Pocket Pathologist, shares practical tips that general practitioners can use in practice when it comes to lymph node cytology.

“I do want to first start by just saying, no matter how long you've been in practice, this is something that is difficult for everybody but does not have to be as difficult as it feels. There are a lot of ways to simplify cytology so that it can be something that you feel comfortable doing in practice,” Baker kicked off her lecture with.

“So I just want to give you that permission and that confidence already if you need it, because it's one of those things that after teaching this for almost 10 years now that I see time and time again, people saying I suck at cytology, but I have to do it, and I understand how that feels,” she continued.

Tips and tricks

Regarding lymph node cytology, Kate Baker, DVM, MS, DACVPM (Clinical Pathology), the biggest issue veterinary professionals have is broken cells. Baker utilized a video submitted by an oncologist where she explains that for the cytology being done for lymph nodes, the subject in the video is removing the syringe off the needle and putting the needle in the lymph node. Then, she stacks the needle around in a few other directions, withdraws it, and checks to see if there are contents in the hub of the needle. Then, the needle is reattached to the syringe, and then putting it onto the slide.

“She's distributing the contents onto several slides because she has quite a bit to spread it out. Because the second thing that we don't want to have in the cytology world are samples that are too thick, so we want to reduce the amount of cell lysis, and we want to spread the sample out,” explained Baker.

Baker emphasized the most important thing here is to not press down. She explained that she understands that things move fast in the clinic and professionals might not be fully paying attention and then just push and spread. However, she warned to not put any downward pressure on the slide, even if you think you are not you could be, so it is important to pay attention because it will help reduce cell lysis.

There are also obviously other things surrounding the lymph nodes that professionals could potentially hit on accident. One common occurrence Baker noted seeing often is veterinary professionals submitting a salivary gland sample thinking it was a lymph node, and although finding it fun, she offered some tips to help understand what the salivatory gland looks like and told attendees it is no big deal, and to not feel embarrassed.

In a salivary gland, there are epithelial cells, which have a glandular appearance to them, and within them is bony saliva. However, you may not get good tissue like the ones that she discussed during her lecture, and it's possible to just get some proteinaceous stuff in the background.

“A clue that you hit the salivary gland is [the] lining up of cells that are called windrowing. So does anybody come from a farming family? Every time we pass a field that has their hay lined up in windrows, I just geek out because I'm like, ‘Oh it's windrows.’ So that's what windrowing is. It's a borrowed term from farming, where they line the hay up and rows,” said Baker.

“We use that term too and see how these red blood cells are kind of moving along in one direction. So that is when you have cells suspended in a viscous material. And saliva is viscous, so that is something that you may see, even if you don't catch these salivary gland epithelial cells,” continued Baker.

A final important note that Baker included is she does see people trying to interpret broken cells and accidentally diagnose a patient with lymphoma because they don’t realize they are looking at the broken cells.

Conclusion

Cytology can be a daunting thing to tackle as a general practitioner, especially if you did not learn a lot about it in veterinary school. However, lymph node cytology is a great tool that veterinary professionals can utilize in their practices so understanding some of the basics involved in the process and having dos and don'ts can save time, resources, and more for veterinary practices and patients.

References

1. Baker K. Lymph Node Cytology for General Practitioners. Presented at: Fetch dvm360 conference; Nashville, TN. May 30-31, 2024.