Differential Diagnosis of Pigmented Lesions in the Oral Mucosa: A Clinical Based Overview and Narrative Review What Caused These Multiple Hyperpigmented Macules of the Mouth? Figure 225 from Pigmentations of the Oral Mucosa and Facial Skin Semantic Scholar 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