Riehl Melanosis MD Searchlight Melanoma Skin Cancer Happy Wednesday! , In this video, a patients labial melanotic macule (a benign pigmented lesion) is being treated with liquid nitrogen. Labial melanotic macules are flat and asymmetrical with a Melanosis coli: a contrast effect or an oncogenic effect? A large scale retrospective cohort study International Journal of Colorectal Disease Springer Nature Link Melanoma Pictures: Skin Changes and What to Look For Melanoma Pictures: Skin Changes and What to Look For