Bcl-2 Immunoexpression in Feline Epitheliotropic Intestinal T-Cell Lymphomas.

Lymphoma is the most common malignant hematopoietic neoplasm in domestic felines. Twenty-two cases of feline epitheliotropic duodenal T-cell lymphoma were characterized morphologically and immunohistochemically (CD3, Pax5, Ki-67), and Bcl-2 immunoexpression was established. Most cases were in domestic shorthair cats (88.2%), with a mean age of 11.2 years. All lymphomas were CD3+, with a low-to-moderate expression of Ki-67 (<30%). A correlation between the tumoral pattern of infiltration in the lamina propria and the intraepithelial distribution of the neoplastic lymphocytes was established (p = 0.0155). Intraepithelial nests of neoplastic lymphocytes were predominantly observed in lymphomas with a patchy distribution in the lamina propria, whereas intraepithelial plaques were seen in lymphomas with an obliteration pattern. Bcl-2 was expressed in neoplastic cells in all cases, and a higher expression was associated with increased villous stunting (p = 0.0221), and tended to be present in those cases with increased epithelial damage. The expression of Bcl-2 and the degree of epitheliotropism were correlated with neoplastic progression in epitheliotropic intestinal T-cell lymphomas; those displaying high Bcl-2 immunoexpression showed increased villous stunting and epithelial damage, suggesting that Bcl-2 is overexpressed in advanced tumor stages, and may be used as a predictor of tumoral behavior in feline epitheliotropic intestinal T-cell lymphomas. This entity showed many similarities with human MEITL, so the latter entity should be considered in further lymphoma classifications of domestic animals.

Feline Gastrointestinal Eosinophilic Sclerosing Fibroplasia-Extracellular Matrix Proteins and TGF-ß1 Immunoexpression.

Feline gastrointestinal eosinophilic sclerosing fibroplasia (FGESF) has been described as an inflammatory disorder with an eosinophilic component with etiopathogenesis that is still unknown. Sixteen intestinal samples from two veterinary diagnostic services (2014-2017) were included in the study. A histopathological criterion classified the cases into three grades (mild, moderate, and severe) according to the distribution of the lesions and the course. An immunohistochemical study of collagen I, collagen III, fibronectin, and transforming growth factor ß1 (TGF-ß1) was performed in each case. An immunohistochemical study of mild grades shows greater collagen III immunoexpression, compared to collagen I and fibronectin, which suggests an "early" stage of fibrosis. In more intense grades, an increased immunoexpression of collagen I, compared to collagen III, suggests a "late" stage of fibrosis. Otherwise, the highest expression of TGF-ß1 was observed in the moderate phase, due to the high proliferation of reactive fibroblast and intense inflammation. The results suggest that the inflammatory infiltrate is the trigger for the elevation in TGF-ß1, altering the collagen type III:I ratio. In conclusion, immunohistochemical studies can be a very useful method in diagnosing cases of FGESF of mild grades and could help to apply a differential diagnosis regarding feline eosinophilic chronic enteritis (CEE) in the context of inflammatory bowel disease (IBD).