Leukoplakia-associated multiple carcinomas in patients with tongue carcinoma.

A series of 522 patients with a diagnosis of squamous cell carcinoma or carcinoma in situ of the tongue were reviewed and followed. Leukoplakia was found in 88 of these patients before and after the diagnosis of tongue carcinoma. A high incidence of multiple carcinomas in the oral cavity and pharynx (116 times greater than expected) was encountered in tongue carcinoma patients. The observed incidence of multiple oral carcinomas in the group with tongue carcinoma with leukoplakia was five times greater than that of the subjects without leukoplakia. The incidence of secondary esophageal carcinomas was also high, 12 times greater than the statistical expection. However, there was no increased occurrence of secondary esophageal carcinomas in the patients with leukoplakia.