Nodular lymphoid hyperplasia of the colon in a vervet monkey (Cholorocebous aethiops)

Diffuse nodular lymphoid hyperplasia (DNLH) of gastrointestinal tract is regarded as a very rare disease in the adult population. It is characterized by presence of diffuse detectable small polypoid masses distributed in the small intestine, colon, or both.

A 6-year-old male in captivity suddenly died, due to myocardial infarction. During routine necropsy procedure, incidentally, numerous tan, sessile polyps, up to 0.2 cm were noticed in all segments of the colon.

Histopathological and immunohistochemical examination revealed polypoid masses as nodular lymphoid hyperplasia (NLH), comparable with DNLH of the colon in human.

In this article, the author has tried to introduce some immunosuppresive (e.g., simian retrovirus type D (SRV), simian immunodeficiency virus (SIV)) and opportunistic viruses (e.g., lymphocryptovirus, γ-herpesvirus, adenovirus), as well as, primary and opportunistic bacteria (e.g., Yersinia psedotuberculosis, and Helicobacter spp.) that may trigger benign reactive process, lymphoid hyperplasia, in non-human primates (NHPs) in captivity.