Influence of Epididymal Anomalies and Development of Processus Vaginalis on Testicular Migration And Cryptorchidism. A Narrative Review.

The objective of this narrative review is to show the most relevant aspects of the structure of epidydimal anomalies (EAs) and processus vaginalis (PV) during testicular migration and in patients with undescended testis. Smooth and striated muscles develop around the processus vaginalis (PV) within the gubernaculum during fetal life. The testis migrates through the PV by the means of peristaltic activity generated by those muscles. After migration is completed, the smooth muscle undergoes programmed cell death, resulting in obliteration of PV and leaving only the dartos muscle. Initiation of programmed cell death requires a shift in autonomic balance characterized by a decrease in sympathetic tone and a concomitant increase in parasympathetic tone. The shift represents a critical step in the migration process. If the shift occurs prematurely, smooth muscle mass decreases before migration is completed, potentially preventing adequate propulsion of the testis and resulting in undescended testis. Premature shift is persistent. Persistence of this shift links the clinical features associated with failed migration. Conversely, if the shift fails to occur or is insufficient, smooth muscle persists and inhibits obliteration of the PV, leading to inguinal hernia or hydrocele depending on the remaining amount of smooth muscle. Epididymal disjunctions anomalies and epididymis atresia could be associated with infertility and are very usual in undescended testis. We can divided EAs in 3 groups: normal variant, disjunction anomalies and epididymis atresia. In the normal variant the epididymis is attached to the testis at the head and tail and totally attached to the testis. The transient presence of SM, its programmed elimination, and regulation by autonomic tone together offer a coherent model that integrates developmental, physiological, and clinical observations. EAs are frequently found in cryptorchidism. Knowledge of anomalies associated with cryptorchidism is relevant in clinical practice, both to prevent accidents during orchidopexy and to counsel and predict infertility in the future, such as in cases of epididymis atresia and total disjunction between the testis and the epididymis.