The diagnosis of carcinoma in transurethral resectates of of the prostate. A study of the probability of overlooking malignant tissue when only part of the material is embedded for histological examination.

The purpose of this retrospective study based on the findings in routinely processed material from fifty-two consecutive cases of prostatic carcinomas is a mathematical calculation of the probability of including a carcinoma in the histological sections from tissue obtained by transurethral resection of the prostate when different embedding practices are followed. The analysis shows that if a material of a composition similar to ours were examined, the calculated probability to include at least one prostatic chip with malgnant tissue in the histological sections would be about 91% if one paraffin-block is made. The probability increases to about 96% when two blocks are used and comes close to 99% with four blocks.