Totally embedded radical prostatectomy specimens and their transurethral resections (TUR) from 32 Stage A (incidental) carcinomas were studied for severe dysplasia. These cases were selected to be representative of the majority of Stage A cancers and hence consisted of cases with predominantly low-grade centrally located tumor. In 43.75% of the cases, severe dysplasia was minimal in amount, 43.75% intermediate, and 12.5% extensive. Severe dysplasia was spatially associated with the main tumor in only 31.25% of cases. In 43.75% of the cases all of the severe dysplasia was isolated (i.e., not adjacent or intermingled with any carcinoma). Whereas this study confirms one general association between severe dysplasia and the presence of carcinoma within the gland, the data do not strongly support the concept that the dysplasia is a direct precursor to centrally located low-grade Stage A carcinomas. From a practical viewpoint, severe dysplasia in the TUR was seen in 15.6% of cases and was not predictive of the amount of tumor within the gland.