[Atypical hyperplasia and latent carcinoma of the prostate as an early stage of carcinoma].

The prostate gland exhibits various borderline lesions and latent prostatic carcinoma is important as a preceding lesion of clinically manifest carcinoma. In this report, we describe a study of these lesions which was carried out using preparations from five different races. Atypical hyperplasia (AH) is the most important of these borderline lesions. Histologically, latent carcinoma exhibits a wide range, from poorly to well differentiated types, and is widely accepted to be the preceding state of clinically manifest carcinoma. Both lesions were common in all five races with a frequency several hundred times greater than the mortality rate for prostatic carcinoma. A significant correlation was found between the prevalences of AH and latent carcinoma, both of which had a tendency to show multifocal growth. Although there were many latent carcinoma cases exceeding 130 mm3 in size and poorly or moderately differentiated, rare cases would advance to clinically manifest carcinoma. Since the formation of tiny carcinomas and progression to clinically manifest carcinoma are two different phenomena, it is considered important to study the factors affecting the latter phenomenon.