Clinical and histopathological evaluation of 13 cases of adenocarcinoma in aged rhesus macaques (Macaca mulatta)

In recent years, the emphasis on aging research, has led to an increase in the number of aged macaques being maintained in some research facilities with a subsequent increase in the occurrence of age:elated diseases. One of the most commonly reported age related diseases is intestinal adenocarcinoma. At the University of Illinois at Chicago (UIC), which maintains a colony of approximately 55 aged rhesus macaques 13 cases of intestinal adenocarcinoma were diagnosed within a 25-month period. This report provides a comprehensive description of the clinical findings for intestinal adenocaremoma in aged rhesus macaques, including results from physical examinations, laboratory tests, radiographic evaluations, gross and histopathologic findings as well as a comparison with the disease condition in humans. The use of carcinoembryonic antigen as a potential tumor marker was evaluated by immunohistochemical analysis of tissue specimens in 10 cases. Intestinal adenocarcinoma is a disease condition that should be of concern to individuals responsible for the care of aged rhesus macaques.