Colitis cystica profunda in rhesus monkeys

Area of Science:

• Veterinary Pathology
• Primate Pathology
• Gastrointestinal Research

Background:

• Colitis cystica profunda (CCP) is a rare condition characterized by submucosal glands and cysts in the large intestine.
• Differentiating CCP from intestinal adenocarcinoma is crucial due to potential misdiagnosis.
• Previous literature describes CCP infrequently in humans and animals.

Purpose of the Study:

• To report the spontaneous occurrence of colitis cystica profunda in non-human primates.
• To compare the incidence of CCP between rhesus monkeys (Macaca mulatta) and squirrel monkeys (Saimiri sciureus).
• To investigate the potential pathogenesis and associated lesions of CCP in these primate species.

Main Methods:

• Post-mortem examination (necropsy) of 28 rhesus monkeys and 20 squirrel monkeys.
• Histopathological evaluation of gastrointestinal tissues to identify and characterize lesions.
• Macroscopic and microscopic assessment for the presence of submucosal glands and cysts.

Main Results:

• Colitis cystica profunda was identified in 4 of 28 rhesus monkeys.
• No cases of colitis cystica profunda were observed in 20 squirrel monkeys.
• An analogous gastric lesion was found in 2 rhesus monkeys with colonic CCP.
• Lesions originated from mucosal extension through the muscularis mucosae, with inflammation implicated as a primary factor.

Conclusions:

• Rhesus monkeys appear susceptible to spontaneous colitis cystica profunda, unlike squirrel monkeys.
• Inflammation likely plays a key role in the development of CCP via mucosal herniation.
• The etiology of the observed intestinal inflammation remains undetermined, with no identified exposure to common toxins.