How Can You Tell if It's Melanoma or Just a Mole? Metastatic oral malignant melanoma transformed from pre existing pigmented lesions in mandibular gingiva: Report of an unusual case 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 Melanotic macules of the tongue in a newborn Journal of the American Academy of Dermatology