Differential Diagnosis of Pigmented Lesions in the Oral Mucosa: A Clinical Based Overview and Narrative Review 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 This lovely patient was thrilled with her beautiful result after laser treatment of oral melanotic macules. I share this case to educate: laser treatment requires accurate diagnosis, an understanding Melanotic macule. Benign. Dark spot on labia (or lip). Analogous to lentigo simplex. Hyperpigmented basal keratinocytes & dermal melanophages. Slight in single basal melanocytes; NO nests. More info like this in Treatment of labial melanotic macules on the lip. These are benign spots that appear on the lips for no apparent reason. The causes are mostly genetic, but similar spots can appear in Laser Lip Treatment for Lip Discoloration: Patient Transformation