Dentistry and Medicine: Pigmentation and Discoloration of Oral and Facial Tissues Diagnosis of oral pigmentations and malignant transformations ScienceDirect Pathology Outlines Melanotic macule Pigmented Lesions of the Oral Cavity Pocket Dentistry 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