Pigmented lesions of the oral mucosa and perioral tissues: a flow chart for the diagnosis and some recommendations for the management ScienceDirect ORAL MELANOTIC MACULE (OMM) (Also called focal melanosis labial melanotic macule) A benign, localized, flat pigmented lesion of the oral mucosa Caused by a focal increase in melanin production Indian patient (mid 70s) with chief concern tongue is turning black. Swipe for more photos. These post inflammatory changes are more common in folks with more melanin in their skin. The underlying Congenital Melanocytic Macule of the Tongue in a Newborn Cureus