Multicystic kidney joined to the homolateral testis by an ectopic vas deferens: embryological hypothesis for a new description.

Ectopic location of the vas deferens is a rare congenital anomaly with multiple variations. The frequent association with ano-rectal abnormalities and hypospadias is well known. We report two cases of a newborn and a 3-year-old child with ectopic vas deferens coupled with a left multicystic kidney without any ureteral structure. Furthermore, the latter had a contralateral vesicoureteral reflux and anal agenesis with recto-bulbar fistula. Our attempt with this report is to explain the development of such anomalous deferential outlet into the multicystic kidney, according to the most qualified theory of the Wolffian duct embryology.