Incidence of carcinoma in situ of germ cells in contralateral testis of men with testicular tumours.

Biopsy specimens from the contralateral testicle in 50 consecutive patients with germinal testicular cancer were examined for carcinoma in situ. Three out of 21 men with seminomas and one out of 29 with other types of germinal cancer (8%) had carcinoma in situ in the contralateral testicle without any clinical signs. One of these men developed early invasive germ-cell cancer 46 months after carcinoma in situ was first diagnosed. The others have been followed up for less than a year without signs of tumour growth. If these results are confirmed routine biopsy of the contralateral testicle in patients with germinal cancer may be indicated.