Unsuspected very small foci of carcinoma of the prostate in transurethral resection specimens

Twenty cases of prostatic carcinoma discovered as small foci in specimens from transurethral resections performed for clinically benign prostatic disease were studied. A representative photomicrograph from each case is shown and the size of the tumor foci in each specimen is demonstrated graphically. As a group, the cases were not significantly different from a control group of 38 clinically apparent but localized cases of carcinoma of the prostate with respect to age at diagnosis, 5-year survival rate, average length of survival and rate of local recurrence. The control group had a significantly higher rate of metastasis during the follow-up period but this was probably attributable to an unusually high proportion of less-differentiated carcinomas. One of the incidentally discovered tumors remained latent until death 11 years, 8 months after diagnosis.