Relative frequency of solitary melanocytic lesions of the oral mucosa Buchner 2004 Journal of Oral Pathology & Medicine Wiley Online Library What Caused These Multiple Hyperpigmented Macules of the Mouth? 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. Congenital Melanotic Macule of the Tongue: Report of Two Cases and Literature Review Head and Neck Pathology Springer Nature Link