[Tumours of the undescended testis (author's transl)].

It has now been clearly demonstrated that cryptorchidism is accompanied by a very marked increase in malignancy of the ectopic testis as well as in that in place. Amongst 80 patients undergoing surgery for carcinoma of the testis 14 (17.5%) had a past history of unilateral undescended. The risk of malignancy developing in an ectopic testis is 12 to 48 times greater than that of a testis which has descended normally. It would appear that the higher the position of the testis, the greater is the risk. Orchidopexy may decreased the risk if performed before the age of 11. When the tumour is situated in an ectopic testis, the clinical picture is often misleading. When the ectopic testis has been brought down the special feature of these tumours is the frequency of spread to inguinal lymph nodes. In terms of its basic principles the treatment of these tumours does not differ from that of those affecting normal testis. The aetiology of these tumours remains uncertain. There would seem to be a consensus in favour of a disgenetic origin, possible secondary to hormonal deficiency.