[Leukoplakia simplex or metaplastic keratosis of the mouth mucosa?].

Leukoplakia simplex lesions affecting the oral mucous membrane of cheeks and the floor of the mouth were characterized from the clinical, histological, electron-microscopical and stereological point of view. An integration of the various observations suggested that a combination of atrophic and metaplastic processes give rise to this type of leukoplakia-lesion which imitates epidermal structures and, therefore, could be defined as a metaplastic keratosis. Possible pathogenetic mechanisms are formulated which might be responsible for and cause this type of oral mucous membrane lesion.