Journal of Veterinary Internal Medicine (Jul 2024)

The diagnostic relevance of mesenteric lymph node biopsy in small intestinal lymphoma in cats

  • Laura Marconato,
  • Valeria Martini,
  • Barbara Banco,
  • Silvia Benali,
  • Veronica Crocchianti,
  • Selina Iussich,
  • Michele Marino,
  • Maria Massaro,
  • Teresa Bruna Pagano,
  • Luca Aresu

DOI
https://doi.org/10.1111/jvim.17095
Journal volume & issue
Vol. 38, no. 4
pp. 2316 – 2323

Abstract

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Abstract Background Regional lymph nodes are frequently sampled in cats with suspected intestinal lymphoma; however, their diagnostic value has not been explored. Objectives To investigate whether histologic and immunohistochemical analysis of mesenteric lymph nodes correlates with the diagnosis of intestinal lymphoma in cats. Animals One hundred 2 client‐owned cats diagnosed with intestinal lymphoma. Methods Retrospective study. The inclusion criteria required a full‐thickness biopsy of the small intestine and concurrent excision of mesenteric lymph nodes. Histologic and immunophenotypic analyses were performed on intestinal biopsies and corresponding lymph nodes. Selected nodal samples diagnosed with reactive lymph nodes underwent clonality testing. Results Transmural T‐cell lymphomas, encompassing small and large cell types, were predominant (64 cases, 62.7%), with large B‐cell lymphomas being more frequently transmural (68.8%) than mucosal (31.2%). Among all lymph nodes examined, 44 (43.1%; 95% CI: 33.9%‐52.8%) exhibited neoplastic infiltration. Among cases of small cell lymphoma, 51 out of 72 (70.8%; 95% CI: 59.4%‐80.1%) showed no nodal involvement. Clonality results correctly identified 19/30 (63.3%; 95% CI: 45.5%‐78.2%) reactive lymph nodes. Concerns were raised regarding clonal identification in the remaining cases and potential misdiagnoses based on phenotypic characteristics. Conclusion and Clinical Importance The study underscores the potential drawbacks of relying solely on mesenteric lymph nodes for diagnosing intestinal lymphomas in cats, particularly small cell subtypes. It emphasizes the importance of full‐thickness biopsies for assessing transmural infiltration and recommends caution when utilizing mesenteric lymph nodes for histologic, immunohistochemical and clonality evaluations in mucosal lymphomas. Despite limitations, this research highlights the need for comprehensive diagnostic strategies in cats with intestinal lymphoma.

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