[Leukoplakia of the oral cavity].

The definition of oral leukoplakia is presently under revision. Most authors do not include anymore the clinical conditions known as cheek and lip biting, frictional keratosis, actinic cheilitis, smoker's palate and other lesions attributed to tobacco, e.g., snuff dipper's lesion. An epidemiological review reveals a prevalence ranging from 0.2 to 11.7% among various population groups. As malignant transformation rate of leukoplakia increases up to 17.5% with time, there is a need for continued observations no matter how long the lesions have been present. Among the aetiological factors, smoking is probably the most important, but industrial hazards in certain factories are responsible for a high prevalence of oral leukoplakia. The tongue and the floor of the mouth are predilection sites for carcinomatous transformation. A histological examination is essential to the diagnosis or confirmation of this premalignant lesion.