Purpose: The frequency, significance and possible etiology of testicular ascent (acquired cryptorchidism) are characterized in light of the known incidence and natural history of congenital cryptorchidism, and data provided by longitudinal and epidemiological studies of ascended testes and orchiopexy rates.
Materials and methods: We comprehensively reviewed the literature addressing the epidemiology of congenital and acquired cryptorchidism and orchiopexy.
Results: The incidence of congenital cryptorchidism in full-term males at birth (2% to 4%) and at age 1 year (approximately 1%) has not increased in the last few decades. The risk of ascent may be as high as 50% in cases where 1 testis is significantly retractile. Ascended testes are typically unilateral (77%), identified in mid childhood and located distal to the inguinal canal (77%). Ascended and significantly retractile testes may be prone to the same germ cell maldevelopment seen in congenital cryptorchidism. Cumulative orchiopexy rates in defined populations are 2% to 4%, and mean age at orchiopexy remains higher than expected (greater than 4 years), despite a long held standard of care that includes recommendation for surgery by age 2. These data suggest that cryptorchidism may be acquired in a significant subset of cases.
Conclusions: With close monitoring of young boys spontaneous ascent of testes from a scrotal to a suprascrotal position may be observed with time, due to either true or apparent testicular ascent, with possible adverse effects on germ cell development and fertility potential. Patients with significant testicular retractility appear to be at highest risk for acquired cryptorchidism, and should be followed closely at yearly intervals until puberty.