Oral Melanoma: A Rare but Aggressive Oral Cancer Oral melanoma is a rare and highly aggressive malignant tumor that develops from melanocytes within the oral mucosa. It most commonly affects the 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 05 May 03 Eng Diagnosis of oral pigmentations and malignant transformations ScienceDirect