have been ruled out, a patient is diagnosed with oral leukoplakia. While the long-term history of these. lesions is impossible to predict, it is known that true leukoplakias are considered “potentially. malignant,” meaning that they have the potential, over time, to develop into oral cancer. Oral leukoplakia occurs in 1-2% of the population and is most common in patients over age 40. It may. affect any part of the mouth.