The spermatocytic seminoma: views on pathogenesis.

The spermatocytic seminoma has clinical and histological characteristics which differ from those of other germ cell tumours of the testis. Classical seminomas and teratomas are believed to originate from intratubular carcinoma-in-situ (CIS), which is almost invariably found adjacent to these neoplasms. In addition, DNA analysis of these tumours and the surrounding CIS has shown both to have an aneuploid distribution. In order to throw light on the origin of the spermatocytic seminoma, we have examined the testicular tissue adjacent to fifteen spermatocytic seminomas for the presence of CIS and assessed the DNA content of the tumour cells densitometrically. In twelve specimens seminiferous tubules were present adjacent to the tumour, and in none of these cases was CIS seen. Nuclear DNA measurements were possible in eleven tumours and in five cases the distribution was diploid, in three cases tetraploid, and only in three cases aneuploid. Therefore, we suggest that the spermatocytic seminoma has a different cell of origin from that of other germ cell tumours of the testis.