DermDx: Brown Macule on Lip Dermatology Advisor 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 Labial lentigines, also called labial melanotic macules, is a benign skin condition that is more common in individuals with darker skin. They most often appear during adulthood although they can develop at Oral pathology: Noting a pigmented macule that often presents a diagnostic dilemma Registered Dental Hygienists Labial Macules: Dark Spots on the Lip Dermatology Advisor