Melanosis Coli and Colorectal Neoplasia

Melanosis coli is a reversible pigmentation of the colonic mucosa characterised by brown or black discoloration caused by the accumulation of lipofuscin in macrophages. It most often arises after prolonged use of stimulant laxatives, particularly those containing anthraquinones, but may also be seen with herbal remedies or other medications. Historically regarded as a benign and incidental finding, recent attention has focused on its potential role as a marker of chronic mucosal injury and its association with colorectal neoplasia. Colorectal neoplasia spans a spectrum from non-neoplastic hyperplastic polyps through adenomatous lesions to invasive adenocarcinoma. Emerging evidence suggests that melanosis coli may coexist with a higher burden of small intestinal ulcers, low-grade adenomas and non-adenoma polyps, raising questions about underlying mechanisms such as increased epithelial turnover, oxidative stress and apoptotic dysregulation. Colonoscopic surveillance often reveals a dose-dependent and distributional pattern of pigmentation, with right-sided and total-colon involvement linked to differing polyp prevalences. Understanding the interplay between melanosis coli and neoplastic transformation has implications for risk stratification, endoscopic detection and patient counselling on long-term laxative use.

Research from Nature Portfolio

No recent Nature Portfolio content available.

Melanosis Coli and Colorectal Neoplasia publication trend

The graph below shows the total number of articles in melanosis coli and colorectal neoplasia across all publications each year (not limited to Nature Index journals).

Technical terms

Melanosis coli: Pigmentation of the colonic mucosa due to lipofuscin-laden macrophages, often reversible and linked to laxative use.

Colorectal neoplasia: Abnormal growth in the colon or rectum ranging from benign polyps (adenomas) to malignant adenocarcinoma.

Anthraquinone laxatives: Stimulant laxatives derived from anthraquinone compounds found in certain plants, which accelerate colonic transit and may induce melanosis coli.

Lipofuscin: A brown-yellow pigment composed of oxidised lipids and proteins, accumulating in long-lived cells or following chronic injury.

Adenoma: A benign epithelial tumour of glandular origin that may serve as a precursor to colorectal carcinoma.

References

1. Review on melanosis coli and anthraquinone-containing traditional Chinese herbs that cause melanosis coli. Frontiers in Pharmacology (2023).
2. Melanosis coli: Harmless pigmentation? A case-control retrospective study of 657 cases. PLOS ONE (2017).
3. Case report: Melanosis coli combined with colon cancer, causality or coincidence?. Frontiers in Surgery (2022).