Melanotan 1 Reviews, Clinical Trials, and Safety Oral Malignant Melanoma Oral Cancer Foundation Information and Resources about Oral Head and Neck Cancer 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. Differential diagnosis of an oral mucosal pigmented lesion: a case of essential melanosis