Canine colorectal proliferative lesions: a retrospective study of 217 cases

BackgroundColorectal proliferative lesions are not common in dogs. However, recently we have observed an increase in the number of diagnosed cases and a lack of publications providing current epidemiological data on lesions of the large intestine in dogs. The aim of this study was a retrospective analysis of 217 canine colorectal non-neoplastic and neoplastic nodular lesions, and assessment of the frequency of occurrence of individual lesions and whether there is a risk of their occurrence depending on age, sex, or dog breed.ResultsHalf of the cases (52.5%) were malignant tumours with a significant predominance of adenocarcinoma (42.9%). In the group of malignant non-epithelial lesions, lymphoma and sarcomas predominated (4.1% and 4.1%, respectively) followed by three cases of plasmacytoma. Benign neoplastic tumours constituted almost one-third of all cases (26.7%) with obvious dominance of adenoma (24.0%). Benign mesenchymal tumours were represented only by leiomyoma (2.8%). The non-neoplastic lesions were represented by a heterogeneous group of polyps (20.3%) with a slight advantage of hyperplastic type (9.7%) and less numerous inflammatory, fibroblastic, lymphoid, and hamartomatous polyps. One case of ganglioneuromatosis in hamartomatous polyp was diagnosed. The vast majority of lesions, both non-neoplastic and neoplastic, were found in the rectum. French Bulldogs were the most numerous breeds in our study, especially among adenomas. Furthermore, benign tumours were diagnosed in younger animals than malignant tumours.ConclusionsThe results of our research provided new data expanding knowledge about the epidemiology of colorectal neoplastic and non-neoplastic proliferative lesions in dogs. Our results indicate that the majority of colorectal proliferative lesions in dogs are malignant, which is alarming. French Bulldogs could possibly be predisposed to proliferative lesions of the large intestine, and this predisposition was statistically confirmed in adenomas. Moreover, benign tumours may occur in animals as young as 1-2 years old.