[Carcinoma in situ of the testis].

Carcinoma in situ (C.I.S.) of the testis is the only known precancerous lesion of germ cell tumours. The prevalence and the incidence of C.I.S. are both unknown, although predisposing factors have been identified: history of germ cell tumour of the contralateral testis, cryptorchidism or history of ectopic testis, decreased fertility or sterility. The incidence is higher in the presence of a combination of several of these factors. No complementary investigations have been demonstrated to be of any value in the detection of C.I.S. which can only be diagnosed, at the present time, by means of surgical biopsy. Once C.I.C. has developed, it never resolves spontaneously. In one half of cases the C.I.S. evolves into an invasive tumour over a period of 5 years. There is no consensus concerning the population in which testicular biopsy should be proposed looking for C.I.S. A large scale C.I.S. screening and detection programme has been proposed in Denmark. However, it is not clear that there is any major gain in testicular cancer morbidity and mortality in comparison with a surveillance programme of patients at risk. Apart from conservative follow-up, two types of treatment can be proposed: orchidectomy or external beam radiotherapy which appears to eradicate the C.I.S. while preserving endocrine function.