Scrotal ultrasound findings in previously congenital and acquired unilateral undescended testes and their contralateral normally descended testis

The aim of this study was to report on different anomalies found by physical examination and scrotal ultrasound in men with previously unilateral congenital undescended testes (UDT; N = 50), acquired UDT (N = 49), their contralateral normally descended testis (CNDT) and control testes (N = 53). Acquired UDT significantly more often had a testicular volume being <15 mL than congenital UDT (88% vs. 68%). In the congenital group, significant differences were found between UDT and CNDT for soft consistency (UDT 36% vs. CNDT 14%), epididymal diameter (UDT 7.6 mm vs. CNDT 8.9 mm), testicular volume (UDT 9.8 mL vs. CNDT 13.8 mL), and inhomogeneous parenchyma (UDT 38% vs. CNDT 14%). In the acquired group, significant differences were found between UDT and CNDT for epididymal diameter (UDT 7.5 mm vs. CNDT 8 mm), testicular volume (UDT 9.3 mL vs. CNDT 14.1 mL), testicular volume <15 mL (UDT 88% vs. CNDT 59%), and inhomogeneous parenchyma (UDT 27% vs. CNDT 6%). The following parameters of congenital UDT, acquired UDT, congenital CNDT, and/or acquired CNDT significantly differed compared with controls: soft testicular consistency (congenital UDT 36%, acquired UDT 20%, congenital CNDT 14%, acquired CNDT 12% vs. controls 0%), epididymal diameter (congenital UDT 7.6 mm, acquired UDT 7.5 mm, acquired CNDT 8 mm vs. controls 9.2 mm), testicular volume (congenital UDT 9.8 mL, acquired UDT 9.3 mL, congenital CNDT 13.8 mL, acquired CNDT 14.1 mL vs. control testes 15.8 mL), testicular volume <15 mL (congenital UDT 68%, acquired UDT 88%, congenital CNDT 66% vs. controls 43%), inhomogeneous parenchyma (congenital UDT 38%, acquired UDT 27%, congenital CNDT 14% vs. controls 0%), and testicular microlithiasis (congenital CNDT 24% vs. control testes 8%). Few differences between congenital and acquired unilateral UDT and congenital and acquired CNDT support the hypothesis of a spectrum of maldescended testes containing congenital and acquired UDT instead of them being two different entities. The CNDT also has anomalies albeit less severe than the UDT, indicating that in unilateral UDT both testes are affected.