Pigmented (Purple or Brown) Lesions in the Mouth Pigmented (Purple or Brown) Lesions in the Mouth Kazemi Oral Surgery Facialart.com Oral Melanotic Macule: Symptoms and Treatment Skinsight Diagnosis of oral pigmentations and malignant transformations ScienceDirect 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.