a Melanotic macule at the wetdry line of the lower lip. b Melanotic Download Scientific Diagram 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 Table 3 from Dermoscopy of venous lake on the lips: A comparative study with labial melanotic macule Semantic Scholar 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