Labial Lentigo (labial melanotic macule) Cancer Therapy Advisor Clinical features of oral pigmented lesions: ( ) Nevus, ( ) melanotic Download Scientific Diagram a Melanotic macule at the wetdry line of the lower lip. b Melanotic Download Scientific Diagram 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.