Malacoplakia of the colon in association with colonic adenocarcinoma

We present two cases of malacoplakia of the colon in association with adenocarcinoma. The foci of malacoplakia characteristically comprised submucosal proliferations of histiocytes and chronic inflammatory cells with the typical cytoplasmic inclusions known as Michaelis-Gutmann bodies. These foci were found, respectively, adjacent to, and in contiguity with, a well- and moderately differentiated colonic adenocarcinoma. The possible pathogenetic relationship between these two processes is discussed.