Acquired undescended testis: When does the ascent occur?

Background Little is known about the timeframe in which acquired undescended testes occur. To guide recommendations for screening examinations, we aimed to (1) specify the ratio of acquired undescended testes in orchiopexy cases and to (2) identify a predisposing age for the development of acquired undescended testis. Methods Three-hundred-forty cases of orchiopexy were retrospectively analyzed and classified as congenital or acquired cases of undescended testis. In acquired cases, the time of the last documented physiological testicular position was obtained. The time of testicular ascent was approximated by calculating the mean between the last physiological finding and orchiopexy. Results In 151 cases (44.4%) prior physiological position of testes was documented and acquired undescended testis was assumed. In 115 of these cases (76.2%) details on the age at last physiological position were available. Ascent occurred between the age of one and fourteen. The 50th, 75th, 85th, 90th and 95th percentile for the estimated age at ascent was 5.8, 7.3, 8.4, 8.7 and 11.1 years, respectively. Conclusions Acquired undescended testes are a common cause of cryptorchidism. Ascent occurs throughout all prepubertal ages, emphasizing the need to regular follow-up of testicular position until puberty. Type of Study Prognosis study. Level of Evidence Level II.