A Rare Case of Oral Mucosal Pigmentation: Differential Diagnosis and Case Presentation JCDA 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. Oral melanotic macule Stock Image C067 2477 Science Photo Library Multifocal pigmentation of the oral mucosa The Journal of the American Dental Association