Differential Diagnosis of Pigmented Lesions in the Oral Mucosa: A Clinical Based Overview and Narrative Review A Rare Case of Oral Mucosal Pigmentation: Differential Diagnosis and Case Presentation JCDA Pigmentation Document Gale Academic OneFile 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 Figure 2 from Oral pigmentation Semantic Scholar