[Squamous cell carcinoma and potentially malignant disorders of the oral mucosa].

Squamous cell carcinoma is the most frequent malignant tumor of the oral mucosa. Various endogenous and exogenous factors promote its development. Therapy and prognosis depend mainly on tumor stage. Early detection is therefore of utmost importance. In most cases cancer develops from "leukoplakia". Both homogeneous leukoplakias as well as "erythroleukoplakias" should be biopsied. The"brush-biopsy", imaging techniques, molecular biologic or DNA tests are not reliable enough at present, often technically demanding and not applicable in daily practice. In extensive lesions "field cancerization" has to be considered. Further important precursor lesions are proliferative verrucous leukoplakia and erosive lichen planus. The management of oral precancerous lesions should be individually tailored: Low-grade dysplasia can be observed. If indicated, patients at risk should be biopsied in intervals. High-grade dysplasia ("carcinoma in situ") should be surgically removed.