Carcinoma-in situ of the human testis: tumour cells are distributed focally in the seminiferous tubules.

The distribution of carcinoma-in-situ was investigated in the longitudinal course of human seminiferous tubules. Serial sections of tubular segments, measuring 9330 microns and 1600 microns in length respectively, were analysed. The tubules exhibited a local accumulation of tumour cells. Areas with abundant tumour cells followed areas that were free of tumour cells. The original coiled configuration of the seminiferous tubules was reconstructed with the help of a three-dimensional crepe rubber model. The model showed that tumour-bearing tubular segments lay close together, even if they were actually situated far distant from each other in the longitudinal course of the tubule. Consequently, distant tubular segments can be attached to a common area of the interstitial tissue. This corresponds to the observation that histological sections frequently show clustered CIS-tubules surrounded by tubules exhibiting spermatogenesis. It is a subject for debate whether the interstitial tissue connects tubular segments to functional testicular units.