Mucosal melanocytic macules 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 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 Labial Macules: Dark Spots on the Lip Dermatology Advisor Congenital Melanocytic Macule of the Tongue in a Newborn Cureus Laser Lip Treatment for Lip Discoloration: Patient Transformation