Association of colonoscopy and histopathological findings of the canine large intestine and ileum abnormalities: 54 cases series

Abstract

Colonoscopy is a minimally invasive technique used to assess the large intestine through direct inspection of the intestinal mucosa. When associated with histopathological examination of fragments collected from the intestine, the definitive diagnosis can be obtained. This retrospective study evaluated colonoscopy and histopathological exams of the large intestine and ileum of dogs with gastrointestinal disorders admitted at the Veterinary Hospital of the Federal University of Minas Gerais (UFMG) and the Veterinary Hospital São Francisco de Assis to determine the frequency of injuries, their distribution in the intestinal segments, and the relationship of the findings observed in these two analyzes. The colonoscopy and histopathological findings of the case series were described using absolute and relative frequencies, as well as nature and intensity classification of the findings. Cohen’s Kappa coefficient was obtained to assess the concordance of nature and intensity classifications between colonoscopy and histopathology, and its 95% confidence interval constructed. The analyses were performed using the Software SAS University Edition. It was observed a moderate agreement between the classification of the nature of the findings by endoscopy and histopathology (Kappa coefficient = 0.39, CI = 0.20-0.59). This can also be observed when assessing the frequency of similar diagnoses between the methods, since only 39 (72.22%) were consistent, i.e., 15 (22.78%) diagnoses differed depending on the nature of the finding, which could have a great influence on the final diagnosis if histopathology was disregarded. For the intensity of the injuries, little agreement was observed between the methods (Kappa coefficient = 0.1243, C = -0.05-0.30). This was even more evident in the frequency of similar diagnoses in terms of intensity, of which 20 (37.04%) were similar and 34 (62.96%) were different. Inflammatory affections are the most frequently observed alterations in the large intestine and ileum of dogs. The most common finding that reveals inflammatory changes is the lymphoplasmacytic infiltrate. As for the proliferative and neoplastic lesions, adenomatous polyps and lymphoma were common. The most affected sites of the large intestine were the descending colon and the rectum. Findings such as edema and reddening of the mucosa were frequent by macroscopy. Although the changes observed by colonoscopy and histopathology may not be similar, these techniques are complementary, which makes biopsies mandatory for a diagnostic conclusion.