Carcinoma in situ of the testis in the presence of contralateral germ cell tumor.

Carcinoma in situ (CIS) of the testis is considered a precursor of germ cell tumor. Diagnosis is made by biopsy, a procedure which is justifiable for patients with increased tumor risk. This group includes patients with testicular tumors who may develop contralateral second malignancies. After obtaining contralateral biopsies from 21 such patients we found one CIS. Treatment consisted of local irradiation (20 Gy) of the remaining testis. No clinical side effects were observed. In a control biopsy 6 months later, no evidence of CIS was found. Leydig cells were morphologically normal. Nine months after therapy, plasma testosterone levels were still normal, LH and FSH levels were increased. Long-term observations are needed to assess the value of radiotherapy as compared to orchiectomy.