Maldescendus testis

Maldescendus testis is a common congenital abnormality occurring in 2-5% of full-term boys at birth in the Western countries. By 3 months of age, the incidence rate spontaneously reduces to 1-2% in this group. The etiology of the disorder is not known, but normal hypothalamo-pituitary-gonadal axis i s usually a prerequisite for normal descent of the testes. Abnormal sexual differentiation is associated with maldescent. However, the majority of boy s with maldescended testes show no endocrine abnormalities after birth. Sev eral defects in developmental genes, such as homeobox genes and Insl3, have been described to cause cryptorchidism in mice, and disturbances in the re gulation of these genes or their mutations may explain etiology of a large pa rt of human testicular maldescent in the future. Increased degeneration of germ cells can be observed in undescended testes after the first year, a nd therefore early treatment is recommended. Surgical treatment is the most effective and reliable method to bring testes into the scrotum, but hormon e treatment with either hCG or GnRH analogues can be considered, particular ly in cases where testes can be palpated in high scrotal position. The effi cacy of hormone treatment is less than 20% and depends on the initial locat ion of the testis. Nonpalpable testes rarely descend with hormone treatment . Both surgery and hormone treatment can have untoward effects. Treatment w ith hCG has been associated with an inflammation-like reaction in the teste s and an increased rate of apoptosis of germ cells leading to a reduced adu lt size of the testes. Vascular complications can occur during surgery, par ticularly in staged orchidopexies. Men with a history of undescended testis have an increased risk of testicular cancer. Impaired fertility is another long-term risk associated to maldescended testes. Fertility potential may be improved by early treatment. Although our knowledge on cryptorchidism ha s increased considerably during the last decades, many questions remain to be answered: Is the incidence rate increasing? What is causing maldescent? Do hormones have any role in the treatment? Copyright (C) 2000 S. Karger AG , Basel.