Labial Lentigo (labial melanotic macule) Cancer Therapy Advisor 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 Brown spots, especially on the lips, can be alarming to some. In some instances it can indicate rare oral mucosal melanoma, however in this case it was a non cancerous labial melanotic macule. a Melanotic macule at the wetdry line of the lower lip. b Melanotic Download Scientific Diagram