Canine Gastrointestinal Neoplasms

Abstract

In a review of 10 270 canine necropsies, 55 neoplasms of the stomach and 64 neoplasms of the small and large intestines were diagnosed. A significant number of these neoplasms were malignant ( P < 0.005) and epithelial ( P < 0.005). Adenocarcinomas of gastric and intestinal origin were in dogs younger than the average age of 10 years. Average age for dogs with connective tissue neoplasms was higher than that for those with adenocarcinomas, and there was a difference in median ages of the various types of neoplasms. There was a higher percentage (65%) of gastric and intestinal adenocarcinomas in male dogs, whereas leiomyosarcomas of the intestines were more frequent in female dogs. Although no breed predisposition was found in dogs with gastric neoplasms, a significant number of the intestinal neoplasms ( P < 0.005), especially the adenocarcinomas, occurred in the Collie ( P < 0.05) and German Shepherd ( P < 0.05) breeds. Twenty-six percent of the leiomyosarcomas also occurred in the German Shepherds. Half of the gastric adenocarcinomas occurred in the pyloric region ( P < 0.005), and the greater curvature was the next most common site. The rectum was the most common site of intestinal adenocarcinomas, then the colon and duodenum. Leiomyosarcomas were more frequent in the intestines and occurred more commonly at sites where adenocarcinomas were less frequent. In contrast to all other types of intestinal neoplasms, primary lymphosarcomas of the intestines usually affected many segments. Four carcinoid tumors of the duodenum and colon were seen. Of the very rare neoplasms, there were two neurilemomas, both of the duodenum and having the same gross and histologic characteristics of this tumor in other locations.