Abstract
Zinner syndrome is a rare congenital malformation of the Wolffian duct with seminal vesicle cyst, ipsilateral renal agenesis and ejaculatory duct obstruction, seen in less than 0.002 % of the male population. An increased awareness among clinicians, urologists, and radiologists is essential, as early diagnosis and management can impact fertility outcomes. This review aims to explain and illustrate Zinner syndrome through imaging case studies. Emphasis is made on considering Zinner syndrome in the differential diagnosis of young males with pelvic pain and renal agenesis, highlighting the importance of radiological evaluation for the management of this uncommon yet clinically significant condition.
Keywords: Zinner's syndrome, Seminal vesicle cyst, Renal agenesis, Wolffian duct anomaly, Ejaculatory duct obstruction, Male Infertility, Oligospermia, Transrectal Ultrasound, MRI pelvis
Highlights
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The classic triad of Zinner's syndrome consists of renal agenesis, seminal vesicle cysts, and ejaculatory duct obstruction.
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Transabdominal ultrasound, TRUS, and MRI are essential modalities to reach an accurate diagnosis.
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Symptomatic patients benefit from surgical intervention, with recent advancements in laparoscopic and robotic-assisted techniques providing optimism for better outcomes.
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Detailed and timely imaging, clinical expertise and early intervention is crucial to diagnose and manage such unique conditions.
Abbreviations:
- CT
Computed tomography
- H&E
Hematoxylin and Eosin
- LIF
Left Iliac Fossa
- MRI
Magnetic Resonance Imaging
- OPD
Out-Patient Department
- TAS
Transabdominal Ultrasound Scan
- STIR
Short Tau Inversion Recovery
- TRUS
Transrectal Ultrasound Scan
- USG –
Ultrasound
- UTI
Urinary Tract Infection
- VUR
Vesicoureteric Reflux
1. Introduction
Zinner syndrome was first described by Zinner in 1914. It is an unusual congenital Wolffian duct malformation characterized by the triad of seminal vesicle cysts, ipsilateral renal agenesis, and ejaculatory duct obstruction. This condition's incidence is estimated to be less than 0.002 % in the male population with only a handful of 200 cases reported to date.1 Normally, both the ureteral buds and seminal vesicles arise from the mesonephric duct. A defect in the formation of the distal/dorsal mesonephric duct results in atresia of the ejaculatory duct, causing obstruction and dilatation of the seminal vesicle.2 Increasing awareness among clinicians, urologists, surgeons, and radiologists is crucial due to the significant clinical and fertility implications of Zinner syndrome. Timely and accurate diagnosis through multimodal imaging techniques is essential to guide appropriate therapeutic interventions and improve patient outcomes, reproductive health, and quality of life.3
2. Case presentation
The first patient is a 38 year old male who presented to the Out-Patient Department (OPD) with symptoms of intermittent perineal and pelvic pain, on and off fever since 8 months, dysuria with burning micturition, occasional haematuria, hematospermia confirmed by urine and semen analysis which also showed oligospermia (3,500,000/milliliter) with reduced volume. Marital history revealed secondary infertility and recent onset painful ejaculation. In view of above clinical findings, a TRUS was advised in suspicion of prostatitis.
TRUS revealed a large complex multilocular cystic lesion with internal echogenic contents, septations and fluid levels arising from the right seminal vesicle. The left seminal vesicle appeared bulky and edematous suggestive of vesiculitis. Dilated right more than left vas deferens secondary to dilated & obstructed distal ejaculatory duct were observed. The proximal ejaculatory duct could not be visualized. Prostate appeared edematous, showing heterogenous echotexture, periprostatic oedema and increased vascularity due to prostatitis (Fig. 1).
Fig. 1.
TRUS shows (A) complex cyst replacing the right seminal vesicle (orange arrow). (B) Bulky and edematous left seminal vesicle with heteroegenous echotexture and increased vascularity suggestive of vesiculitis (blue arrow). (C) Dilated right more than left vas deferens (black arrow) secondary to ejaculatory duct obstruction. Heterogenous and edematous prostate with periprostatic oedema and increased vascularity suggestive of prostatitis (red arrow). (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)
A provisional diagnosis on TRUS was suggestive of right complex seminal vesicle cyst. A differential diagnosis of right seminal vesicle abscess was also considered. Patient underwent an extensive antibiotic course and came for a follow up scan after 1 month with no significant interval change in the volume of the cystic lesion. However, there was some intermittent improvement in his clinical symptoms with no further worsening. Patient was further planned for TRUS guided aspiration and drainage.
However, an out of the box follow-up scan with a vigilant and timely abdominal ultrasound beyond the eyes and need of the clinical symptoms was done which incidentally revealed an absent right kidney with compensatory hypertrophy of the left kidney (Fig. 2). Now, a diagnosis of an associated Wolffian duct abnormality was made and MRI pelvis was suggested to confirm the diagnosis.
Fig. 2.
TAS shows (A) complex cyst replacing the right seminal vesicle and abutting the bladder posterior wall (yellow arrow). (B) absent kidney with empty renal fossa (grey arrow). (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)
MRI of the abdomen and pelvis showed a large complex multilocular cystic lesion appearing T2 hyperintense with no diffusion restriction. T1 hyperintense fluid levels were noted within suggestive of haemorrhagic contents. The cyst was arising from the right seminal vesicle and abutting the bladder, right iliac vessels and levator ani. Left seminal vesicle appeared mildly bulky, edematous with T2 hyperintensity and few small cystic changes suggestive of vesiculitis. Absent right kidney with compensatory hypertrophy of left kidney was suggestive of renal agenesis. Thorax screening showed no obvious ectopic kidney. Also, the prostate appeared heterogeneously hyperintense on T2-weighted sequence with periprostatic oedema and few tiny cystic areas in the periphery with no diffusion restriction suggestive of prostatitis (Fig. 3). A final diagnosis of Zinners syndrome was made.
Fig. 3.
(A) MRI pelvis T2 axial sequence shows a complex cyst with hemorrhagic fluid levels (red arrow) arising from right seminal vesicle. (B) MRI pelvis T2 coronal sequence shows the same cyst (red arrow). Also shows left seminal vesiculitis with cystic changes (yellow arrow). (C) Coronal T2 MRI of abdomen shows absent right kidney in right renal fossa (grey arrow). (D) Axial STIR MRI pelvis shows edematous prostate with altered hyperintense signal suggestive of prostatitis. (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)
The second patient is a 26 year old male who presented with recurrent UTI and diffuse lower abdominal pain. TAS and TRUS showed a tubular dilated fluid filled structure arising from the region of left seminal vesicle extending from the pelvis to LIF. Small anechoic fluid filled outpouchings were seen at the anterior wall of urinary bladder. The prostate volume was low for age and bilateral vas deferens were dilated secondary to ejaculatory duct obstruction. There was associated left renal agenesis (Fig. 4).
Fig. 4.
TRUS depicts (A) Left seminal vesicle cyst (green arrow). (B) Tubular nature of the seminal vesicle cyst (green arrow). (C) Small blind ending outpouching in the anterior wall of urinary bladder (black arrow). (D) Small volume of prostate for age (orange arrow). Dilated right and left vas deferens (blue arrow). (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)
MRI confirmed the diagnosis of a wolffian duct abnormality variant (Zinner's syndrome). A tubulocystic lesion arising from left seminal vesicle with blind ending in LIF was possibly suggestive of an ectopic megaureter remnant. Absent left kidney was suggestive of agenesis. Small fluid signal outpouchings at anterior wall of bladder hinted at rudimentary ectopic ureters. Prostatic hypoplasia & dilated vas deferens were also seen (Fig. 5).
Fig. 5.
(A, B, C) T2/STIR MR coronal and axial sections of lower abdomen, pelvis show tubulocystic structure arising from left seminal vesicle with blind ending in LIF (yellow arrows). (D) T2/STIR MR coronal section of pelvis shows ectopic rudimentary ureter remnants (grey arrow) at anterior wall of urinary bladder in proximity with the prostate. (E) MR Urogram 3D reconstruction shows the tubulocyst in LIF (green arrow) with absent left kidney (red arrow). (F) H and E at 40X of the tubulocyst shows transitional epithelial lining (black arrow), muscularis layer (blue arrow) and adventia (red arrow) suggestive of an ureter remnant. (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)
The imaging findings for both cases were confirmed post laproscopic excision of the cyst indicating high accuracy. Both the patients showed significant resolution of the symptoms post surgery. There was no obvious recurrence of the cysts on follow up USG in both.There was an improved sperm count (5,400,000/milliliter) in the first patient at 8 months follow up. Histopathological examination of the tubulocyst from second case revealed transitional epithelial lining, muscularis and adventitia layers suggestive of an ureter remnant (Fig. 5-F).
3. Discussion
Patients usually present during the third to fifth decade of life with complaints of lower abdominal pain, recurrent urinary tract infections (UTIs), perineal pain, recurrent prostatitis, hematospermia, painful ejaculation, and infertility.4 Atypical symptoms, including intermittent scrotal pain and prostatic utricle cysts, have also been observed.
Many other developmental abnormalities are associated with this pathology, such as congenital absence of the vas deferens, ipsilateral ectopic ureter, rudimentary ureter, megaureter, contralateral renal anomalies, cryptorchidism, vesicoureteric reflux, testicular hypoplasia, Müllerian duct abnormalities and prostatic abnormalities including cysts.5 It is also scarcely reported to be associated with renal cell carcinoma, prostatic adenocarcinoma, and testicular germ cell tumours.6 A rare and unique instance of villous adenoma of the colon associated with congenital seminal vesicle cyst has also been reported.7
Transabdominal ultrasound is the initial imaging modality that reveals renal agenesis and pelvic cysts. Transrectal ultrasound is extremely valuable in evaluating the seminal vesicles and prostate. The complexity of the cyst (multi-locules, septations, nodules, vascularity, calcification, wall thickness, internal contents), associated prostatitis, or ejaculatory duct obstruction can be better assessed. It is also useful in guided biopsies or aspirations if needed. CT urography helps in the detailed evaluation of the urinary tract and associated anomalies, such as vesicoureteral reflux. It helps in the detection of secondary complications like hydronephrosis or infections. A contrast study can help differentiate cystic and solid masses, aiding in the exclusion of neoplasm and in the visualization of vascular structures in relation to the cyst.8
MRI pelvis is the gold standard investigation, helping in the precise characterization of the nature of seminal vesicle cysts. T2-weighted images highlight the fluid-filled cysts while T1-weighted images can identify haemorrhagic contents within. Other associated anomalies involving the ureters, prostate, testes, kidneys and Müllerian duct derivatives can be evaluated.9 Nuclear medicine scans can help assess renal function and confirm the absence of the kidney. Early and accurate imaging diagnosis is essential for appropriate management.
Treatment depends on the symptomatology. Asymptomatic patients are managed conservatively while symptomatic patients are managed surgically with transperitoneal laparoscopic cyst excision. Laparoscopic unroofing was better than fenestration under vesiculoscopy in terms of symptoms and fertility outcome.10 The surgical criteria for cyst excision is generally less than 10 cm. However, a 12.5 cm seminal vesicle cyst was excised without any complication in one study.11 More recently, robotic assistance has been used in the excision and draining of these cysts with wall marsupialization to prevent recurrence. The prognosis of Zinner syndrome is generally favourable, particularly when the condition is diagnosed early and managed appropriately. There is a low risk of recurrence when the cyst is fully excised.12
4. Conclusion
A skillful, detailed and prompt radiological imaging coupled with clinical expertise is essential to diagnose such unique and rare conditions as Zinner syndrome. Early intervention may improve fertility outcomes and quality of life for patients.
Availability of data and material
Not applicable.
CRediT authorship contribution statement
V. Pramod: Writing – review & editing, Writing – original draft, Visualization, Methodology, Investigation, Formal analysis, Data curation, Conceptualization. S.C. Sanjay: Writing – review & editing, Validation, Supervision, Resources, Project administration. S. Tanuj Sai Kumar: Investigation, Data curation.
Patient consent
Written informed consent has been obtained for publication. The images are anonymized to protect patient identity and privacy.
Financial Support
Nil.
Use of artificial intelligence
No.
Funding
Nil.
Conflicts of interest
No.
Acknowledgment
We extend our heartfelt gratitude to the staff, residents, and technicians of the Radiodiagnosis Department at Kempegowda Institute of Medical Sciences for their unwavering assistance and support. We sincerely thank the Pathology, Urology, and Surgery Departments for their significant contributions. Lastly, we are deeply appreciative of the patients who participated in this research.
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Data Availability Statement
Not applicable.