Labial Melanotic Macules in Atopic Dermatitis: An Observational Study Semantic Scholar In the process of removing a Labial Melanotic Macule. A Labial Melanotic Macule is a well defined, oval, brown to black, flat patch on the central third of the lower lip, as seen 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