Melanosis coli involving pericolonic lymph nodes associated with the herbal laxative Swiss Kriss: a rare and incidental finding in a patient with colonic adenocarcinoma.

Melanosis coli is a well-known condition in which macrophages filled with a lipofuscin-like pigment are found in the colonic lamina propria. The condition has been associated with the ingestion of anthracene laxatives and is believed to be caused by increased epithelial apoptosis. Although melanosis coli is a frequent finding in colonic biopsies and resection specimens, to our knowledge the presence of identical pigment in macrophages of pericolonic lymph nodes has been reported in only 4 other patients in the English literature. We report the case of a patient who underwent a left hemicolectomy for colonic adenocarcinoma and was found incidentally to have melanosis coli associated with long-term use of the herbal laxative Swiss Kriss, not only in his colonic mucosa, but also in the colonic submucosa and in his pericolonic lymph nodes.