1. Histopathologic, phenotypic, and molecular criteria to discriminate low-grade intestinal T-cell lymphoma in cats from lymphoplasmacytic enteritis.
- Author
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Freiche V, Paulin MV, Cordonnier N, Huet H, Turba ME, Macintyre E, Molina TJ, Hermine O, Couronné L, and Bruneau J
- Subjects
- Animals, Cats, Cohort Studies, Intestines, Prospective Studies, Cat Diseases diagnosis, Enteritis diagnosis, Enteritis veterinary, Lymphoma, T-Cell diagnosis, Lymphoma, T-Cell veterinary
- Abstract
Background: Differentiation of low-grade intestinal T-cell lymphoma (LGITL) from lymphoplasmacytic enteritis (LPE) in cats is a diagnostic challenge for pathologists., Objective: Characterize histologic, immunohistochemical, and molecular features of LGITL and LPE., Animals: Forty-four client-owned cats, 22 diagnosed with LGITL and 22 with LPE., Methods: Prospective, cohort study. Clinical suspicion of LGITL or LPE was based on persistent gastrointestinal signs, unresponsive to empirical treatments. All cats underwent a standardized diagnostic evaluation, including biopsy (preferentially full-thickness), and were diagnosed with LGITL or LPE after review of clinical, laboratory, sonographic, histologic, immunohistochemical, and clonality results., Results: A monomorphic lymphocytic population (22/22, 100%) and in-depth mucosal infiltration (15/22, 68%) were hallmarks of LGITL. Epithelial patterns (nests and plaques) were significantly more frequent in LGITL (11/22, 50%) than in LPE (1/22, 5%) cases (P = .001). A CD3+ lymphocytic apical-to-basal gradient was observed in 9/22 (41%) of LGITL vs 1/22 (5%) of LPE cases (P = .004). Most LPE cases (17/18, 94%) featured marked fibrosis in the superficial part of the lamina propria. The Ki-67 20%- and 30%-thresholds discriminated between LGITL and LPE within both the epithelium (specificity >95%) and lamina propria (specificity >95%), respectively. All LGITL cases were CD3+ pSTAT3- and pSTAT5+. T-cell receptor gamma chain gene rearrangements indicated monoclonality in 86% of LGITL cases. Surprisingly, 70% of LPE cases featured monoclonality (40%) or monoclonality on a polyclonal background (30%)., Conclusions and Clinical Importance: We identified new histologic, immunohistochemical, and clonality criteria to distinguish LGITL from LPE., (© 2021 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals LLC on behalf of American College of Veterinary Internal Medicine.)
- Published
- 2021
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