Pre-malignant lesions of the oral mucosa in a South African sample--a clinicopathological study.

The clinicopathological features of 130 cases of leukoplakia and 8 patients with erythroplakia of the oral mucosa are reviewed. Cases were selected on the basis of definitions agreed to at an international seminar. The patients with leukoplakia were predominantly men, (1.5:1), most were White (86.2%) and the peak age frequency was the 7th decade. The sites most frequently affected were the buccal mucosa (28.8%), floor of mouth (18.3%), alveolar ridge and gingivae (17.3%) and tongue (12.0%). Clinically, they were classified as homogeneous leukoplakia (70.6%), erythroleukoplakia (11.2%), verrucous leukoplakia (10.6%) and nodular leukoplakia (7.6%). There were no differences in age or site distribution between the sexes but the women tended to have more nodular and verrucous lesions. Most of the patients were smokers (71.5%). There was a highly significant sex difference (p less than 0.01) in the use of tobacco with 42.3 per cent of the women and 19.2 per cent of the men never having used tobacco. The tobacco users were significantly younger (p less than 0.05). Of the 143 lesions biopsied, 60.8 per cent showed no dysplasia, 28.0 per cent mild or moderate dysplasia, 4.2 per cent severe dysplasia/carcinoma-in-situ and 7.0 per cent verrucous or squamous carcinoma. Homogeneous leukoplakias have a very low frequency of dysplasia while in the case of the other clinical types the frequencies of dysplasia and malignancy are substantially higher reaching 33.3 per cent invasive malignancy in the case of the nodular lesions. The sites at greatest risk are the floor of the mouth, soft palate, alveolar ridge/gingivae, tongue and buccal mucosa in order of decreasing frequency.(ABSTRACT TRUNCATED AT 250 WORDS)