Pseudomelanosis coli, its relation to laxative use and association with colorectal neoplasms: A comprehensive review

Abstract

Pseudomelanosis coli is historically associated with anthraquinone laxatives and is often used as a surrogate marker for chronic laxative use. The opioid epidemic has seen an increase in laxative use for chronic constipation. Anthraquinone laxatives have demonstrated tumorigenic potential in animal studies due to their apoptotic effects on colonic epithelial cells. Colorectal cancer is associated with significant mortality and morbidity worldwide. Human studies have not shown a significant correlation between anthraquinone laxative use, pseudomelanosis coli, and colorectal carcinoma. The characteristic pigmentation of pseudomelanosis also appears to be absent macroscopically and on histology of neoplastic epithelium. However, there appears to be a slightly higher risk of adenoma development. This has been attributed to a higher polyp detection rate during endoscopy on account of the color contrast between the polyp against a darker background of pseudomelanosis.

Clinicopathological Appearance of Epidermal Growth Factor-Containing Fibulin-Like Extracellular Matrix Protein 1 Deposition in the Lower Gastrointestinal Tract: An Autopsy-Based Study

“…Five cases in the small intestine case group and 10 in the colon case group had a medical history of constipation and/or were taking laxatives, including magnesium oxide, sennoside, and lubiprostone, and/or showed pseudomelanosis coli, which suggests the presence of constipation [16]. One patient had diverticulosis.…”

Review on melanosis coli and anthraquinone-containing traditional Chinese herbs that cause melanosis coli

“…Anthraquinone laxatives have been demonstrated to have tumor-inducing potential in animal studies. Exposing to an anthraquinone-containing diet for 480 days induced 25 colorectal cancer in rats; another animal study showed that using anthraquinone laxatives for 112 days developed 4 adenocarcinomas and 5 adenomas in the large intestine of rats ( Mohammed et al, 2021 ). However, a prospective case control study demonstrated that the long-term use of anthraquinone laxatives was not associated with increased risk for colorectal adenoma or colorectal cancer ( Nusko et al, 2000 ).…”

A Rare Finding of Gastric Pseudomelanosis in Chronic Kidney Disease: A Case Report

“…Pseudomelanosis is defined as a benign, dark, speckled pigmentation within the subepithelial macrophages of the lamina propria layer in the enteric wall [ 1 ]. While it is most commonly found in the colon and associated with anthraquinone laxative use, cases have been reported in the small intestine as well as the stomach, with the incidence significantly decreasing more proximally [ 2 ]. The incidence in the large intestine has been reported between 0.82% and 1.13%, with a staggering 95% of those patients disclosing they take anthraquinone laxatives [ 2 ].…”

“…While it is most commonly found in the colon and associated with anthraquinone laxative use, cases have been reported in the small intestine as well as the stomach, with the incidence significantly decreasing more proximally [ 2 ]. The incidence in the large intestine has been reported between 0.82% and 1.13%, with a staggering 95% of those patients disclosing they take anthraquinone laxatives [ 2 ]. On the contrary, to the best of our knowledge, only eight other reported cases of gastric pseudomelanosis were previously found in the literature [ 3 , 4 ].…”