[Role of testicular biopsy in the investigation of a carcinoma in situ].

Carcinoma in situ (CIS) of the testis is recognized to be a precursor of cancer. Radiological examinations are not sufficient to improve the diagnosis. So the diagnosis is made by testicular biopsy. The indications are controlateral testis biopsy in man with testicular cancer and risk factors (cryptorchidism, dysgenetic gonads...) and extragonadic germ cell tumors. The authors review the risk factors. Chemotherapy is not sufficient to eradicate the CIS. A dose of 16 Gy of localized radiation is curative, excludes bilateral orchidectomy and preserves androgen function and azoospermic patient.