[The clinicopathological analysis of melanoma of the oral mucous membrane].

Forty-one cases with melanoma of the oral mucous membrane were studied by clinicopathology and immunohistochemistry. The incidence of the tumor is higher in old males. The mean age of patients is 46.15 years. The ratio of male to female is 2.15: 1. The tumor occurs most commonly in palate (46.34%), followed by gingiva, then lip, buccal and tongue membrane. The oral melanosis had been found in 41.46% of the cases months to years before tumour appeared and 51.22% of cases had concurrent or later-developing melanosis. The epithelium around tumour in 14 cases with pre-existing melanosis was observed. We found that the number of clear cells and s-100 protein positive cells in epithelium increased, and a lot of cells filled with melanin in the lamina propria were found. The result shows that the patients with this preexisting melanosis have higher risk of suffering from malignant melanoma.