Lichenoid dysplasia – A historical overview and current debates

Oral lichen planus and oral lichenoid mucositis are the two most common lichenoid lesions of the oral cavity. Oral lichen planus is classified as a potentially malignant condition by the World Health Organization, and lichenoid mucositis has also been shown to have malignant potential. However, some argue that lichen planus or lichenoid mucositis is only premalignant when dysplasia has developed in these lesions and that many cases of lichen planus or lichenoid mucositis with cancer development were in fact either a lichenoid lesion with dysplasia or a primary dysplasia misdiagnosed as oral lichen planus or lichenoid mucositis due to the coexistence of lichenoid features. Here, we summarize what is known about the risk of malignant transformation of these lesions and discuss the ongoing controversies surrounding the diagnostic criteria.