Colitis cystica profunda in rhesus monkeys.

Spontaneously occurring colitis cystica profunda, characterized by the presence of non-neoplastic glands and mucin-containing cysts in the submucosa of the large intestine, was observed post mortem in 4 of 28 rhesus monkeys (Macaca mulatta) but in none of 20 squirrel monkeys (Saimiri sciuresu) necropsied during the same period of time. An analogous lesion in the stomach was present in 2 of the monkeys with the colonic condition. The submucosal glands and cysts resulted from extension of the mucosa through the muscularis mucosae, and inflammation was considered to have played a primary role in this process. The cause of the intestinal inflammation was not determined, and there was no known exposure to toxic chemicals, including pesticides and polychlorinated biphenyls. Colitis cystica profunda affecting man and other animals has been described infrequently in the literature, but the importance of differentiating it from intestinal adenocarcinoma has been emphasized.