A Case Report of Oral Malignant Melanoma: A Silent Killer Cureus Figure 7 from Pigmented lesions of the oral mucosa and perioral tissues: a flow chart for the diagnosis and some recommendations for the management. Semantic Scholar Pigmentation Document Gale OneFile: Health and Medicine 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 (OMM) (Also called focal melanosis labial melanotic macule) A benign, localized, flat pigmented lesion of the oral mucosa Caused by a focal increase in melanin production