RESUMO
An important part of tumor prevention is early detection, dia-gnosis, treatment and screening of precancerous conditions. Correct detection and screening of premalignant lesions leads to early dia-gnosis of a malignant process which provides a better chance to completely cure the patient and also predicts better quality of life. Precancerous conditions look like whitish, red or mixed mucose lesions (leukoplakia, erytroplakia, erytroleukoplakia) which are visible during clinical examination. Nevertheless, these mucose changes are not absolutely conclusive. Therefore, histological testing is necessary for dia-gnosis and determination of bio-logical potencial of precancerous lesions. Precancerous lesions as a term of histological terminology means dysplasia. The risk of progression of dysplasia into a carcinoma depends on a grade of dysplasia. The conservative or surgical treatment is chosen according to localisation and grade of dysplasia.
