Objective: To investigate the significance of the acquired undescended testis (UDT), which is differentiated into congenital and acquired forms, by assessing the previous testicular position in affected boys.
Patients and methods: The study comprised 261 boys who had been referred for a non-scrotal testis to the outpatient clinic during an 8-year period (1993-2000). There was a bimodal distribution of age, with peaks at 2.0 and 10.0 years. In each boy with UDT the previous testicular position was ascertained.
Results: On referral, 340 testes were not in the scrotum (182 uni- and 79 bilateral). Of the 340 testes, 82 (24%) in 61 boys were diagnosed as retractile, whereas the remaining 258 in 221 boys were undescended. The previous testicular position was known in 208 of 221 boys (94%), with 244 UDTs. In 65 of these 244 (26.6%) the testis had never been scrotal (congenital UDT); in 179 (73.4%) a previous intrascrotal position was recorded in early childhood (acquired UDT) at least once, in 149 (61%) at least twice and in 117 (48%) at least three times. The mean age at referral for congenital UDT was 2.1 years and for acquired UDT was 8.4 years.
Conclusions: These results show that acquired UDT is frequent, and occurs at about three times the rate of congenital UDT. Because these boys are referred for treatment later in childhood, the acquired UDT probably accounts for the high rate of (late) orchidopexy.