Biopsy-Proven Melanosis Coli Initially Diagnosed As Candidiasis on Colonoscopy: A Report of Two Cases From North Central Nigeria

Melanosis coli is a benign condition, often identified as an incidental finding during colonoscopy, characterized by brown or black pigmentation of the colonic mucosa due to lipofuscin deposition within the cytoplasm of cells. It has been linked to the excessive use of laxatives, particularly those that are anthraquinone-based but also stimulant laxatives and herbal remedies. White patches on colonoscopy in this condition are an extremely rare finding. We present two cases of 31- and 38-year-old, male Nigerians, with a history of chronic constipation and prolonged stimulant laxative use in whom colonoscopy findings of white patches on the colonic mucosa were confirmed on histology to be melanosis coli. Melanosis coli should be considered in the differential diagnosis of patients with chronic constipation and/or prolonged use of laxatives or herbal remedies who exhibit mucosal changes on colonoscopy even if these changes are not black or brown discolorations.