Oral Melanotic Macule: Symptoms and Treatment Skinsight AD :: Annals of Dermatology A Rare Case of Oral Mucosal Pigmentation: Differential Diagnosis and Case Presentation JCDA Melanosis coli Wikipedia 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.