Dental Update Malignant oral melanoma: how to spot it and how it is managed Dental Update Oral Malignant Melanoma Oral Cancer Foundation Information and Resources about Oral Head and Neck Cancer COM Jan. 2008 Diagnosis UW School of Dentistry 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.