Quantitative Analysis of Melanosis Coli Colonic Mucosa Using Textural Patterns This is a very rare case of metastatic oral mucosal melanoma to the colon with an unusual presentation mimicking melanosis coli. The colonoscopy findings show no mass effect but multiple hyperpigmented lesions Melanosis coli is dark brown black pigmentation of colorectal mucosa associated with chronic use of laxatives containing anthraquinone. Examples of such laxatives include senna and rhubarb derivatives. Clinical Importance: There is no association Pathology Outlines Melanosis coli An unusually pigmented colon The Lancet Gastroenterology & Hepatology