Pathogenesis and treatment of undescended testes.

Impaired intrauterine gonadotropin secretion was the cause of cryptorchidism in 78% of cryptorchid boys studied. On the one hand, this impairment implied the underdevelopment of the epididymis and thus the cryptorchid state of the gonad. On the other hand, the histological alterations of the testis, due to impaired gonadotropin secretion were Leydig cell atrophy and an impairment in the number of the germ cells. The secondary damage, due to the unfavorable position, started during the second year of life. To avoid this damage, early treatment is highly recommended. Hormonal treatment with GnRH is the treatment of first choice. This treatment was successful in 60% of cryptorchid boys. An additional treatment of nonresponders with low doses of hCG increased the overall success rate to 80%. Six months after treatment, 14.5% of those successfully treated suffered a relapse.