Colonic adenocarcinoma associated with chronic colitis in cotton top marmosets, Saguinus oedipus.

Colitis is a common disease of cotton top marmosets, Saguinus oedipus, characterized by crypt abscesses and inflammation of lamina propria. In more advanced colitis there is marked irregularity of mucosal surface, distortion of crypt architecture and epithelium, increased numbers of mitoses, and decreased numbers of goblet cells. Foci of pleomorphic cells arranged in poorly formed glands or sheets, interpreted as carcinoma in situ, also occur. Many such cases have invasive colonic adenocarcinoma with metastasis to colonic lymph nodes but not elsewhere. Analysis of necropsy data from a group of 210 marmosets in captivity for 3.5 yr revealed that the incidence of advanced colitis, adenocarcinoma in situ and invasive carcinoma increased markedly over that period. A strong association between colitis and adenocarcinoma was suggested by both morphologic and epidemiologic data.