Zinner Syndrome: A Diagnostic Challenge. The Aid of Morphology, Embryology, and Immunohistochemistry.

We investigate a patient with right kidney agenesis. Imaging showed the presence of a cystic mass dislocating the bladder. The specimen showed three formations: a kidney remnant, a ureter with blind-ending branch, and a cyst, from which departed another tubular structure, considered the deferential duct. The specimen was sampled. The supposed kidney was formed by cystic structures. Examination of the tubular structures disclosed smooth muscle fibers with no lumen, whereas the cyst was surrounded by fibrous and hemorrhagic walls. Collaboration among specialists allowed the diagnosis of Zinner syndrome, a congenital malformation due to an abnormal development of the Wolffian duct.