[Unilateral agenesis of structures dependent on the mesonephric duct. Presentation of a case].

The mesonefric duct plays an essential role in the development of the genitourinary tract. From that duct derive structures as the ureter, the vas deferens and the seminal vesicles. Also, the ureteral bud interact with the mesonefric blastema and induce its conversion to renal tissue. The origin of these anomalies of the embrionary development is unknown. In some cases, mutations on the gene of the cystic fibrosis (CFRT) could play a role, assuming that there is a relationship between the congenital absence of the vas deferens and the cystic fibrosis. Usually, the absence of these structures has a silent course. Thus, the most important diagnostic factor is the clinical suspicion. The knowledge of this association can lead to the diagnosis of other congenital abnormalities. In addition, it is important to know that these anomalies could be present isolated as expression of other non-urological diseases, specially the cystic fibrosis, the most common hereditary disease between the Caucasian race.