Melanoma Pictures: Skin Changes and What to Look For Despite the name "melanosis," the pigment isn't melanin. The Pigment: It is actually lipofuscin, a "wear and tear" pigment. The Process: Anthraquinone laxatives cause apoptosis (cell death) of the colonic epithelial cells. Abuse of laxatives and melanosis coli Pigmented Lesions and Melanoma Plastic Surgery KeyPlastic Surgery Key Melanotic Neuroectodermal Tumor of Infancy MD Searchlight Primary Acquired Melanosis (PAM)