A surgical oncology expert shares her tips for getting an accurate and useable biopsy for next step diagnostics
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In the realm of diagnostics, obtaining a diagnosis without resorting to a biopsy is generally more favorable for the client. A biopsy should generally not be seen as a first line diagnostic. However, in certain cases, biopsy can be the first choice such as in the skin and bones in which these areas have a diagnostic efficiency with about 90% of cases.1
In a 2024 Veterinary Meeting & Expo session, Brittany Ciepluch, DVM, MS, DACVS-SA, ACVS Fellow Surgical Oncology, stated, “For bones, cytology is my preference. Cytology is highly diagnostic for bone lesions. I mostly see neoplasia, so maybe that’s my bias, but if you can get away with doing cytology—that is the preferred method.”1 Additionally, the decision to perform a culture may come into play, particularly when diagnosing infections, where obtaining tissue samples takes precedence over surface swabbing since the infection lives inside the tissue.
Overall, primary lesions should be sampled. These could be a papulue, pustule, nodule, or erythema. Collect secondary lesions if they are extensive and mark these samples as such. Secondary samples would come from any crusts, scale, or collarettes.
Some other tips for collecting samples include the following:
For a bone diagnosis, Ciepluch recommended using cytology because, in her opinion, it is easier, less expensive, safe, and has a high accuracy. The only weakness with cytology is that histopathology agrees with only about 27% of cases with non-neoplastic bone lesions.3 “So if you’re not suspicious of neoplasia, maybe a bone biopsy will be your better bet,” Ciepluch said. However, Ciepluch stated that if your patient/client is considering a limb spare procedure, then avoid doing a bone biopsy.
In general, if cytology doesn’t give the diagnosis or it is not an option, then a bone biopsy can still be used. “A couple of additional principles for bone biopsy: we want to have strict asepsis, definitely stricter than skin or mouth biopsies. Hemostasis is important. You want to get deep into the bone, so you need to penetrate that near cortex, you don’t want to penetrate the far cortex. And then, offering the owners the risks that come with [this diagnostic], which include hematoma, infection, fracture, and possibly getting a non-diagnostic sample,” Ciepluch said. To avoid providing a nondiagnostic sample, Ciepluch stated to make sure you are taking the biopsy from the middle of the lesion and getting far enough in that you get into the medullary canal.
References
1. Ciepluch B. Perfecting the biopsy: Skin, mouth, and bones. Presented at: Veterinary Meeting & Expo; Orlando, Florida; January 13-17, 2024.
2. Henfrey JI, Thoday KL, Head KW. A Comparison of Three Local Anaesthetic Techniques for Skin Biopsy in Dogs. Vet Dermatol. 1991;2(1):21-27. doi:10.1111/j.1365-3164.1991.tb00106.x
3. Sabattini S, Renzi A, Buracco P, et al. Comparative Assessment of the Accuracy of Cytological and Histologic Biopsies in the Diagnosis of Canine Bone Lesions. J Vet Intern Med. 2017;31(3):864-871. doi:10.1111/jvim.14696
