COM Dec. 2011 Diagnosis UW School of Dentistry Oral Melanotic Macule An Unusual Occurrence In Gingiva Journal of Health and Allied Sciences NU Differential Diagnosis of Pigmented Lesions in the Oral Mucosa: A Clinical Based Overview and Narrative Review 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.