Content continues after advertisement

Lymph Node Status in Canine Mast Cell Tumors

Sarah Boston, DVM, DVSc, DACVS, ACVS Founding Fellow of Surgical Oncology, ACVS Founding Fellow of Oral & Maxillofacial Surgery, VCA Canada, Newmarket, Ontario, Canada

Oncology

|December 2019

Sign in to Print/View PDF

In the Literature

Ferrari R, Marconato L, Buracco P, et al. The impact of extirpation of non-palpable/normal-sized regional lymph nodes on staging of canine cutaneous mast cell tumours: a multicentric retrospective study. Vet Comp Oncol. 2018;16(4):505-510.


FROM THE PAGE …

Identifying lymph node status in mast cell tumors (MCTs) is important for determining prognosis and whether further staging is necessary. Although palpation and cytology of regional lymph nodes are often performed, their value is limited; thus, histopathology remains the gold standard.1-3 It is generally understood that enlarged lymph nodes should be removed in all cases, but less is known regarding how to manage lymph nodes that are normal in size or nonpalpable, as well as how to definitively diagnose metastatic disease on histopathology. A recent study categorized lymph nodes as HN0 (nonmetastatic), HN1 (premetastatic), HN2 (early metastasis), or HN3 (overt metastasis), according to the degree of metastatic cell aggregates present and evaluation of lymph node architecture.4

In the current study, the authors aimed to assess the metastatic rate of nonpalpable or normal-sized regional lymph nodes in dogs with MCTs. Included in the study were 93 dogs with solitary cutaneous MCTs that were negative for distant metastasis. Regional lymph nodes that were nonpalpable or normal in size were removed, and clinical characteristics, including tumor size and histologic grade, were evaluated. Of the 93 dogs, 46 were found to have histologically detectable metastatic disease. The only clinical factor significantly associated with metastatic disease was a tumor diameter >3 cm.

These study findings highlight the importance of regional lymph node removal at the time of MCT removal. Lymph node status is important for staging and potential chemotherapy decision-making and may also guide the need for further staging, as MCTs tend to metastasize to the regional lymph nodes before becoming widely metastatic.5 Removal of metastatic lymph nodes may also provide a survival advantage.6 Regional lymph node removal was a high-yield test in this study; however, further investigation is needed to determine whether sentinel lymph node mapping would be a more effective method of staging.7


… TO YOUR PATIENTS

Key pearls to put into practice:

1

Palpation characteristics are an insensitive method for detecting metastatic disease in MCTs and many other cancers.

 

2

The use of the Patnaik 3-tier8 and Kiupel 2-tier9 histologic grading systems in this study highlights a problematic issue with the Patnaik system. Patnaik grade II MCTs are the most common MCT classification10; however, this study found discrepancies between the Patnaik grade II classification of some lymph nodes when they were compared with the Kiupel grading system. These discrepancies create a gray area in how to manage Patnaik grade II MCTs.

3

Removal of the regional lymph node with MCT resection may yield a high rate of metastatic disease, as seen in this study.

 

4

Larger MCTs (>3 cm) have a higher rate of nodal metastasis.

References

For global readers, a calculator to convert laboratory values, dosages, and other measurements to SI units can be found here.

All Clinician's Brief content is reviewed for accuracy at the time of publication. Previously published content may not reflect recent developments in research and practice.

Material from Clinician's Brief may not be reproduced, distributed, or used in whole or in part without prior permission of Educational Concepts, LLC. For questions or inquiries please contact us.

Podcasts

Clinician's Brief:
The Podcast
Listen as host Alyssa Watson, DVM, talks with the authors of your favorite Clinician’s Brief articles. Dig deeper and explore the conversations behind the content here.
Clinician's Brief provides relevant diagnostic and treatment information for small animal practitioners. It has been ranked the #1 most essential publication by small animal veterinarians for 9 years.*

*2007-2017 PERQ and Essential Media Studies

© 2023 Educational Concepts, L.L.C. dba Brief Media ™ All Rights Reserved. Terms & Conditions | DMCA Copyright | Privacy Policy | Acceptable Use Policy