We present a case of Zinner syndrome (ZS), where we were fortunate to diagnose a child with this rare syndrome immediately after birth. Gross hydronephrosis was observed during the prenatal period on ultrasound, and further imaging after birth confirmed the presence of a multicystic dysplastic kidney and seminal vesicle cyst. The majority of cases of ZS is asymptomatic; however, symptoms relating to urination, ejaculation or infertility may present later on in life and so regular follow-up is required to ensure interventions can be carried out if such symptoms do occur.
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Zinner syndrome (ZS) is a rare diagnosis affecting men, with only 50 cases reported in the paediatric population. Furthermore, only 12 cases have been reported in infancy; however, most patients remain asymptomatic.1 Moreover, there have been rare reported cases of malignancy in adult patients.2 Hence, careful understanding of this syndrome and follow-up of patients are necessary to avoid morbidity and mortality from this treatable condition. ZS occurs due to an abnormality of the Wolffian duct during embryogenesis, presenting with a triad of seminal vesicle cyst (SVC), ipsilateral renal agenesis or multicystic dysplastic kidney and ejaculatory duct obstruction; however, other pelvic cystic structures must be ruled out with initial investigations.3
The patient presented to the outpatient department at our institute in his early infancy, who had full-term normal vaginal delivery and normal milestones for his age. He did not have any history of surgery or medical comorbidities at presentation. The patient had been asymptomatic since birth; however, abnormalities had been noted on ultrasound during pregnancy. He was previously investigated at other hospitals.
Antenatal ultrasonography (USG) done at a private clinic at 25 weeks gestation diagnosed a left-sided gross hydroureteronephrosis with a pelvic anteroposterior diameter of 12 mm and 21 × 10.5 mm curved tubular structure seen posteroinferior to the urinary bladder. The remainder of the findings was normal for the patient’s age. Another USG was repeated 4 days after birth at the same private clinic, which revealed similar findings. Serum creatinine of the baby 1 week after birth was 0.6 mmg/dL, and urine routine microscopy showed 2–4 pus cells/High power field which were within normal limits for his age. At the age of 1 month, the patient underwent contrast-enhanced CT scan of the abdomen at another private clinic and was diagnosed with a 5.2 × 4.7 × 6 cm multicystic area in the left renal fossa with no renal contrast excretion on the left side suggestive of multicystic dysplastic kidney (figure 1). It also showed a tubular dilated structure along the course of the left ureter which is seen traversing posterior to the urinary bladder into the rectovesical pouch (figure 1). The patient presented to our institute with the above investigations already performed. A DMSA scan was subsequently carried out, in which the left kidney was non-functioning/not visualised.
MRI abdomen including KUB region was done at 4 months of age and showed left gross hydronephrosis with atrophic parenchyma with the left renal pelvis communicating with left ureter and the blindly ending ureter (figure 2). A 34 × 24 mm multilobulated cystic lesion adjacent to the urinary bladder communicating with the prostatic urethra was suggestive of an SVC. The left seminal vesicle was not visualised separately from the cystic structure. The right seminal vesicle was visualised.
The case was discussed with radiology department, and a repeat USG was done at 6 months of age which showed similar findings of gross hydronephrosis on the left side (6.29 × 4.3 cm) and a lobulated cystic lesion (3.5 × 2.3 cm) posteroinferior to the bladder base on the left side. A voiding cystourethrogram done at 6 months of age showed a bladder capacity of 30 mL, dilated posterior urethra, irregular bladder wall, no vesicoureteric reflux (VUR) and a postvoid residue of 5 mL (figure 3). A note was made of a saccular structure on the posteroinferior side of the bladder on the left side on anteroposterior view which was not seen on the postvoid images.
The patient was further planned for cystoscopy which was delayed due to the COVID-19 pandemic and the subsequent lockdown. On relaxation of stringent lockdown rules, a cystoscopy was performed, at which point the patient was over 1 year old. This showed a normal urethra and bladder wall in which the right ureteric opening was visualised as normal; however, the left ureteric orifice (UO) was not seen.
There are some important diﬀerential diagnoses to consider when diagnosing pelvic cystic lesions postnatally.3 4 First, prostatic utricular cysts (PUCs) should be ruled out given their midline position and communication with the urethra, along with their association with bilateral seminal vesicles and erectile dysfunction. A very common characteristics of younger patients with PUC include differences in sex development, with other features such as VUR, hypospadias and cryptorchidism noted. Another differential diagnosis would be Müllerian duct cysts (MDCs); however, these do not communicate with the urethra. Furthermore, MDCs typically do not occur at such a young age but with older individuals. On the other hand, individuals diagnosed with MDCs often have normal external genitalia with the pelvic cyst often in the midline, as seen in ZS. It is pertinent to note that both SVCs seen in ZS and ejaculatory duct cysts (EDCs) arise from the Wolﬃan duct, whereas PUC and MDC develop from Müllerian ducts. Wolﬃan duct cysts are paramedian and often are associated with upper urinary tract abnormalities.5 6
EDCs should also be considered, again due to their midline nature. Another differential would be an ectopic hydronephrotic pelvic kidney or ureter, with further alternative diagnoses being ureterocoeles or possibly bladder diverticula explaining the retrovesical collection.5–7 Distinctions between each of these bladder abnormalities can be made using their position in relation to the bladder neck (lateral, paramedian or median) or by identifying and grouping them together with concomitant anomalies of the urogenital tract.5–8 For example, an ectopic hydronephrotic pelvic kidney appears as a cystic pelvic mass, similar to ZS. Contrast excretion would be noted along with an aberrant artery inflowing the ectopic kidney. In a similar fashion, bladder diverticula are both cystic and paramedian, again like ZS. On the other hand, bladder diverticula can be ruled out in a patient with ZS given the normal seminal vesicles and definitive diagnosis on cystoscopy. A less likely but nonetheless important differential to exclude would be ectopic ureterocoeles as they would show as pelvic structures, lateral in location; however, they are most usually found at the lower end of the ureter.9
It is important to note that although we have focused mainly on the differential diagnoses of pelvic cysts postnatally, but antenatally also, pelvic cysts can have a wide range of differentials. These may be urinary tract related such as ureterocoeles, urachal abnormalities, urinomas and renal cysts. Other non-urinary tract related abdominal cysts can be observed antenatally, such as cystic neuroblastomas, choledocal cysts, meconium cysts, lymphangiomas or enteric duplication cysts to name just a few .10 It is also extremely important to mention the possibility of abdominal neoplasms such as teratomas which may be a reason for early delivery of the fetus.11 Despite this, it is rare for intra-abdominal cysts to affect management in the prenatal period or require early delivery of a fetus; however, many fetuses that have persisting cysts after birth do require some form of surgical intervention.
Given the asymptomatic presentation of our patient, he was treated conservatively. Cystoscopy was done which revealed normal urethra and normal right UO. The left UO was absent, and the rest of the findings was normal.
Outcome and follow-up
Asymptomatic or minimally symptomatic patients can safely be managed conservatively with long-term follow-up; therefore, we have planned for a long-term follow-up of our patient, at least until he reaches adolescence.
ZS is a rare congenital disorder, first described in 1914 by A Zinner.12 It is characterised by an ipsilateral upper urinary tract along with malformation of the seminal vesicles. The syndrome can also be identified by the triad of an SVC, ipsilateral renal agenesis or multicystic dysplastic kidney and ejaculatory duct obstruction. The patients are usually diagnosed in their second to third decade of life when they become sexually active. Common symptoms at presentation include epididymitis (27%), dysuria (37%), perineal pain (29%) and frequency (33%).13 14 It is considered to be the male equivalent of Mayer-Rokitanksky-Kuster-Hauser syndrome seen in women,15 which presents as an underdeveloped or non-existent uterus and vagina, often diagnosed following investigations for primary amenorrhoea. Occasionally, the cysts in ZS can be greater than 12 cm, and these are aptly named ‘giant’ cysts. Their large size can cause obstructive symptoms of both the bladder and colon.16 Conversely, smaller cysts can also be seen in ZS, and patients with cysts less than 5 cm in size often remain asymptomatic. As a consequence of this, they may only be found incidentally on digital rectal exam, presenting as a palpable fluctuant mass on the superior aspect of prostate gland. Alternatively, patients with ZS with small cysts may present with vague, varied symptoms, such as ejaculatory pain, haematospermia and infertility.17 Rare reports of papillary adenocarcinoma and squamous cell carcinoma have been reported in SVCs associated with renal agenesis between 17 and 41 years of age, and no patient in paediatric age group developing seminal vesicle malignancy has been mentioned in literature.18 19 Although there are no clear guidelines to screen patients for carcinoma, but in our opinion patients with rapid and progressive symptoms should be observed and kept under regular follow-ups considering the possibility of development of malignant tumours in seminal vesicle.
SVCs may be congenital or acquired. Insufficient drainage of gland secretions is the basis of cyst formation, and when linked with atresia, can go on to cause distention of the seminal vesicles.20 Importantly, the seminal vesicles and kidneys have an inter-related embryological origin. The adult kidney arises from the metanephric blastema, the differentiation of which is induced by the ureteral bud arising from the dorsal aspect of distal mesonephric duct. Following this, the mesonephric duct will go on to form many structures, importantly for ZS, including the seminal vesicle, ejaculatory duct and hemitrigone.21 Embryological development of the kidney is reliant on the stimulation of the ureteric bud and mesonephric duct. In cases where the mesonephric duct fails, this causes the ipsilateral kidney to not develop, along with failure of development of ipsilateral ureter, hemitrigone and seminal vesicle. Emptying of the distal ureteral bud into structures derived from the mesonephric duct, such as the bladder neck, seminal vesicle, vas deferens, ejaculatory duct or urethra can be explained by delayed absorption of the caudal mesonephric duct. This occurs when the ureteral bud arises in a more cephalic position off the mesonephric duct.21 22 As such, the embryological origins of the urinary tract and genitalia combined with the causes of failure of correct development provide the background for the rare association of SVCs and agenesis or dysplasia of the ipsilateral kidney. Ipsilateral renal agenesis combined with SVCs communicating with ectopic ureters is rare, and may be further complicated by obstruction or reflux; however, cases describing this have been published.23
Many paediatric patients with ZS are now being diagnosed incidentally on antenatal imaging, and USG is usually the first technique used for imaging.24–26 Despite this, other imaging modalities provide important information not available on USG. Pelvic anatomy can be accurately imaged and renal anomalies can be identified on a CT scan, along with the classical thick irregular bladder wall, solid mass and enlargement of the ipsilateral seminal vesicle describing a cystic pelvic mass. Associated renal anomalies can also be clearly identified on CT, as well as the retrovesical mass and its communication with the seminal vesicle, cephalic to the prostate gland. Despite this, MRI is the imaging study of choice for ZS. This is mainly due to the increased signal intensity of SVCs on both T1- and T2-weight scans. This may possibly be reflecting the increased concentration of proteinaceous material or haemorrhage. Furthermore, MRI may be in surgical planning when preparing to excise SVCs as the patient’s anatomy, and anatomic relationships can be accurately visualised. In our case CT was already done by some other clinicians, but since MRI is better, therefore we performed MRI.
Congenital SVC treatment remains a widely debated subject with the gold standard a controversial topic. Conservative management is commonplace for patients who are either asymptomatic or minimally symptomatic, but they remain under long-term monitoring.25 Surgical treatment during childhood is advocated only in symptomatic cases. Open or transurethral unrooﬁng of the cysts,26 vesiculectomy with the resection of renal remnants, with or without vasoligation are the other options available in the armamentarium for treatment of this condition. Surgical management is more common in the adult population, with numerous techniques described, such as retropubic, transvesical, perineal, transrectal and transanal approach. There has been a description of a seminal vesicle sparing surgery treatment by Valla et al who performed a near-total cystectomy, with a thin strip of cyst wall left remaining together with the vas, thus aiding the possibility of preserving the patient’s fertility and sexual potency.27
I was worried when I came to know about my son during initial investigation. My child was referred from various general practitioners after multiple investigations. As a mother I was concerned about the prognosis of the child. All their worries were addressed in a sequential manner and the need for regular follow up was explained to me and I am happy that a diagnosis has been made and I will definitely follow the plan of management.
Zinner syndrome (ZS) is diagnosed very rarely in the paediatric age group.
ZS is a key differential diagnosis of cystic pelvic masses with associated ipsilateral renal anomalies in men.
MRI is the imaging study of choice with ultrasonography and CT also playing vital roles in both the diagnosis and management of ZS.
Asymptomatic or minimally symptomatic patients can be safely managed conservatively with long-term monitoring allowing surgical treatments to be reserved for symptomatic patients.
Patient consent for publication
Twitter @joanne_m_rose, @RaviBanthia_uro
Contributors This report was supervised by HL, he conceived the manuscript and provided MRI and voiding cystourethrogram images. RB, ZT and JMOR prepared the manuscript. Consent was taken by RB. JMOR did editing and grammer check . HL and JMOR reviewed the manuscript. The final draft was read and approved by all authors.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Case reports provide a valuable learning resource for the scientific community and can indicate areas of interest for future research. They should not be used in isolation to guide treatment choices or public health policy.
Competing interests None declared.
Provenance and peer review Not commissioned; externally peer reviewed.