Diagnóstico diferencial del linfoma intestinal y la enfermedad inflamatoria crónica intestinal en biopsias endoscópicas caninas

Abstract

Inflammatory bowel disease (IBD) and small intestinal lymphoma are relevant diseases in canines, responsible of a large number of cases of chronic vomiting and diarrhea. Both conditions share clinical presentation; however, a correct diagnosis is essential for proper treatment and prognosis. The differentiation of intestinal lymphoma from IBD is based on the histological evaluation of intestinal biopsy specimens. However, when IBD is severe and intestinal lymphoma diffuse, the differential diagnosis can be difficult, especially in endoscopic biopsies. For this reason, this study focuses on the evaluation of complementary diagnostic procedures such as immunophenotyping, proliferation index Ki-67 and PCR to determine clonality of the infiltrating cells, in order to establish a differential diagnosis between the two diseases. Endoscopic intestinal biopsies from 32 dogs that presented with diffuse, severe, intestinal disease were selected. All dogs were divided into three groups after morphologic evaluation with routine stains and assessment of CD3 and CD20 stained slides. Groups were: Lymphoma group (n = 9), IBD group (n = 8), and LPD group (lymphoproliferative disorder, n = 9). LPD group included dogs with a non conclusive diagnosis of lymphoma suspect. Results of the current study demonstrate no significant differences among groups in terms of presenting complaint, clinical signs and blood tests. Ultrasonographic data revealed that increased intestinal wall thickness and loss of intestinal wall layers are significantly more frequent in Lymphoma group (p = 0,020 and p = 0,001 respectively). Endoscopic visualization of the intestinal mucosa is similar within the three groups, showing an irregular, hyperemic mucosa, with the presence of erosions or white foci in some animals. Mucosal consistency at the time of biopsy collection differed significantly among groups. Friability was more frequent in IBD group (p = 0,015) whereas increased mucosal consistency was more frequent in Lymphoma group. WSAVA histopathological standards for the diagnosis of intestinal inflammation in endoscopic biopsy samples (Day et al., 2008) were evaluated. All cases of Lymphoma group presented an inflammatory background, associated with the neoplastic process. WSAVA index appeared significantly higher in Lymphoma group (p = 0,005). Furthermore, villous stunting and villous epithelial injury were significantly more intense in Lymphoma group (p = 0,022 and p = 0,004 respectively) ...