A Rare Case of Oral Mucosal Pigmentation: Differential Diagnosis and Case Presentation JCDA 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 smokers, after Oral melanoma and other pigmentations: when to biopsy? Lambertini 2018 Journal of the European Academy of Dermatology and Venereology Wiley Online Library PT 141 (10mg) Canlab International