Complete Testis-Epididymis Nonfusion Anomaly: A Typical Association with Cryptorchid Testis

Introduction: Fusion anomalies of the testis and epididymis are associated with cryptorchidism. We present an analysis of the fusion anomalies of the epididymis in cryptorchid boys. Patients and Methods: We performed a retrospective review of patients presenting with undescended testes between 1986 and 1993. Patients were stratified among four groups based on the degree of testis-epididymis nonfusion. Results: A total of 880 testes were eligible for review, of which 93% (815/880) had normal fusion, 3.6% (32/880) had epididymal head nonfusion, 2% (19/880) had epididymal tail nonfusion, and 1.6% (14/880) had complete nonfusion. Increasing degree of nonfusion was associated with higher perioperative testes position. Head and tail nonfusion were observed together with a contralateral descended testis, but less frequently than in bilateral undescended testes (p = 3.89×E–10). Complete nonfusion was not observed in the contralateral descended testes in unilateral cryptorchid boys. Conclusions: Different degrees of fusion anomalies of the epididymis are associated with unilateral and bilateral undescended testis, indicating that nonfusion anomalies interact with epididymal-testicular descent because of impaired epididymal function.