Quantitative histologial studies on 4 testes removed because of carcinoma-in-situ (CIS) were performed in order to determine the distribution of CIS within the testis and to estimate the likelihood of diagnosing testicular CIS by biopsy. The CIS changes were distributed in all parts of the testes but were less frequent in the parts adjacent to the epididymis. In the 4 testes examined 1.4 to 599 of the entire testicular volume contained seminiferous tubules with CIS. In parts of the testes where more than approximately 10% of the testicular volume consisted of tubules with CIS all simulated biopsies measuring 3 mm contained the lesion. The same was true for simulated biopsies measuring 1.5 mm when more then approximately 30% of the testicular volume consisted of tubules with CIS. If the distribution of CIS generally is similar to that found in the 4 analysed testes there seems to be a high probability of detecting the disease by one or two testicular biopsies.
Keywords: atypical germ cell; carcinoma-in-situ; human; infertility; morphometry; testicular histology; testis.