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. Metastatic oral malignant melanoma transformed from pre existing pigmented lesions in mandibular gingiva: Report of an unusual case ScienceDirect PDF] Oral melanoacanthoma and oral melanotic macule: a report of 8 cases, review of the literature, and immunohistochemical analysis. Semantic Scholar Labial Melanotic Macules DoveMed