In both genders the genital tract originates from the mesonephric duct (Wolff duct) and the paramesonephric duct (Mullerian duct), which undergo a specific differentiation trajectory. Both systems are connected to the urogenital sinus and to the external genitalia, contributing to their development.

The Vas deferens, seminal vesicles and ejaculatory ducts derive from the mesonephric duct which opens on the side of the prostatic utricle. The epididymal appendix, bladder hemitrigone and ureteral buds also derive from this structure. For this reason, an anomaly in the mesonephric duct’s evolution may induce both internal genital malformations and renal agenesis.

Anomalies of these interactions cause malformations and alterations of sexual differentiation.

Among these complex syndromes, Zinner syndrome is a rare condition which shows some similarities with the first case described and is characterized by the following triad: obstruction of ejaculatory ducts, seminal vesicles cysts and omolateral renal agenesis [3].

In patients affected by Zinner syndrome the first symptoms appear more often from the 2nd to the 4th decade of life, at the beginning of their sexual activity [3]. Symptoms include abdominal, pelvic and perineal pain, painful ejaculation, reduced sperm volume and LUTS. The first patient described presented a clinical condition that could be a variant of Zinner syndrome, considering the presence of deferens duct cyst, seminal vesicle agenesis and omolateral renal dysplasia. Another anamnestic peculiarity of this patient is the presence of Hirschprung disease (congenital megacolon). In the literature there are studies which hypothesize an association between urinary tract malformations and congenital megacolon. This is related with the presence of a correlation between a gene deletion of RET (rearranged during transfection) or GDNF (Glial Derived Neurotrophic Factor) and alterations of renal organogenesis and the enteric innervation [4, 5]. More recently, associations between urinary tract malformations, congenital megacolon and 16p11.2 microdeletions have been discovered [6]. Moreover, the fact that seminal vesicles cysts are associated with ipsilateral renal agenesis in 68% of cases should be taken into account; in the absence of genitourinary abnormalities, this condition should be considered as an acquired disease [7].

Suprapubic or transrectal ultrasound is often the initial diagnostic imaging tool. Urethrocystoscopy and voiding cystourethrography are also useful diagnostic tests for these conditions. Nevertheless, the gold standard for the diagnosis of male pelvic floor cysts is MRI [1, 2]. Differential diagnosis between intraprostatic and extraprostatic cysts is performed with clinical and radiological findings, while histopathological characterization of the cystic wall is usually not significant. However, few cases of malignant cyst of Muller duct (adenocarcinomas and squamous cells carcinomas) have been described. Surgical treatment is recommended in symptomatic patients and in case of obstructive azoospermia. There are different treatment modalities including: trans-rectal drainage, transurethral resection of ejaculatory ducts (TUR-ED), robotic, laparoscopic and open surgery. Endoscopic treatment could be reserved to small lesions. This approach is characterized by lower morbidity, but it has the disadvantage of a higher recurrence rate [7], as reported in our first case.

In our opinion, open surgery is recommended in large masses and in patients who underwent previous surgery where a laparoscopic approach could be more challenging and have a higher complication rate. The following surgical approaches have been described: extravesical, transvesical, trans-rectal, perineal. The urethral fistula and the late purulent pelvic collection described in our case could be related to a local and systemic infection confirmed by the clinical, laboratory and intra-operative findings. The surgical drainage of the purulent collection, antibiotic therapy and prolonged bladder catheterization have permitted a complete clinical resolution. During the last years, robotic and laparoscopic surgery offered advantages such as image magnification, reduced blood loss, minor invasiveness and morbidity and better preservation of anatomical structures. Nowadays, laparoscopic treatment is the gold standard while robot-assisted surgery is limited to few cases and is associated to higher costs [8, 9].

Surgical treatment is reserved for symptomatic patients. In asymptomatic patients surveillance is an acceptable option. Pre-operative counseling is important in order to inform the patient about the potential complications such as infertility and erectile dysfunction. Patients must be adequately informed about risks and benefits of the surgical approach in order to reach a shared diagnostic and therapeutic decision making. In this context semen cryopreservation is useful and advisable before surgery.