Premalignant Lesions and Conditions of the Oral Cavity

Oral cancer develops in precursor lesions referred to as the group of premalignant disorders (PMDs) by the World Health Organization (WHO). Some lesions are relatively common affecting between 1 and 5% of the population (leukoplakia) and may resemble benign and prevalent mucosal disease. These lesions pose a risk for malignancy that is independent of tobacco or alcohol, with a wide range of transformation rates between 13 and 70%. The commonest types are white patches (leukoplakia), red patches (erythroplakia) and submucous fibrosis. Knowledge of the patterns of clinical presentation of PMDs is important in order to screen patients effectively, identifying those who benefit from a close observation, those who require from targeted biopsy and those who may be safely followed up in primary care. We describe clinical features of the most well-documented premalignant disorders discussing lesion-specific risk predictors and treatment options. We also present a brief outline of the less prevalent group or premalignant systemic conditions including those that predispose to the development of mucosal squamous carcinoma and those that associate with the development of cutaneous squamous carcinoma. Genetic pathways involved in the development and progression of PMDs are outlined, and finally, we describe best practices for carrying out a diagnostic tissue biopsy.