Adenocarcinoma of the cecum with Crohn's-like features in baboons.

During the past 9.5 years, 51 baboons dying as a result of chronic diarrhea and poor health and having a chronic inflammatory process of the cecum (i.e. typhlitis) were recorded. The cecum was turgid, irregularly thickened the lumen reduced and the mesenteric lymph nodes enlarged. Of the 45 baboons with well preserved histologic material, 24 had shallow ulcerations and/or focal mucosal inflammation, 3 had crypt abcesses, 3 had mucosal fissures,l aphtoid ulcerations, and 1 pseudopyloric metaplasia (ulcer associated cell lineage-UACL-). The submucosa in all 45 animals was thick due to fibrosis, 35 had focal chronic inflammation with lymphoid aggregates, 12 submucosal abcesses, 6 epithelioid cell granulomas, 5 fissures reaching the submucosa, 3 neural hyperplasia of the myenteric plexus, and 2 lymphangiectasia. Focal chronic transmural inflammation with lymphoid aggregates was recorded in 44 animals. In addition, 2 animals showed deep fissure tracts. Ten of the 45 animals had in addition a cecal adenocarcinoma; one was overlayed by a villous adenoma with high grade dysplasia. Liver metastasis was found in another animal. The present study indicated that a) baboons may develop transmural chronic focal inflammation in the proximal colon (cecum), b) the inflammation in baboons closely mimic Crohn's disease of the cecum in humans c) adenocarcinomas in baboons with Crohn's-like inflammatory changes may originate in an adenomatous growth, and d) cecal adenocarcinomas in baboons with Crohn's-like inflammatory changes of the cecum, are able to metastasize.