[Therapy of cryptorchidism. Viewpoints for optimizing fertility].

The pathophysiology of cryptorchidism--the most common anomaly of the urogenital tract--is still not well understood. Delayed treatment results in reduced fertility and even after correct therapy the risk of malignancy after puberty remains elevated. Intra-uterine maternal hCG stimulation and a postpartal GnRH rise in conjunction with a nor-mal hypothalamus-pituitary-gonadal-axis are essential for the normal development of the germ cells. Disturbances in these key-events of hormonal stimulation lead to a pre-pubertal hypogonadotropic hypogonadism with impaired fertility. Only the early beginning of hormonal therapy, best done sequentially (GnRH + hCG), can promote the physiologic descend and normal fertility. Surgery, even if performed early enough, has little impact on the physiology of germ cell development, cannot alter the risk of subsequent malignancy and improves only the cosmetic appearance. To reach optimal fertility each not descended testicle should be treated primarily using hormonal therapy.