Women's Health Supplements Town & Country Compounding Peptide Therapy in Atlanta Xperience Health Pigmentation (melanosis) of the colon Stock Image C009 6107 Science Photo Library Leopard skin appearance on colonoscopy. Melanosis coli is a condition characterized by dark brown or black pigmentation of the colon lining, often resulting from the prolonged use of anthraquinone laxatives like senna Photomicrograph of an endoscopic colon biopsy (colonoscopy) showing melanosis coli, an accumulation of brown pigment (lipofuscin) within macrophages of the colonic mucosa, related to use of laxatives. Stock Photo Adobe Stock 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