Lichenoid lesions of oral mucosa. Diagnostic criteria and their importance in the alleged relationship to oral cancer.

Lichen planus and other lichenoid disorders of oral mucosa occur commonly, and yet they are poorly understood. Further, the question of the premalignant potential of oral lichen planus remains deeply mired in controversy. The object of this article is to delineate these problems, clarify the issues, and present evidence to support the position that true lichen planus of oral mucosa is not only less common than generally appreciated but also has no inherent predisposition to become malignant. Rationale and data from the literature are offered in support of this position.