Testicular tumor and crytoptorchidism.

71 (7.2%) of 990 patients with testicular tumors were either clinically cryptorchid or had a history of maldescendent testis. 3.4% of the tumors arose in untreated or unsuccessfully treated testicular nondescent. Ipsilateral and contralateral development of malignancy were equally common. Neoplastic changes were even observed in patients who had undergone corrective surgery prior to their 5th year of life. There was no predominating histologic type of tumor.