Painful ejaculation, difficulty passing urine or trouble conceiving can have many causes. One uncommon explanation is Zinner syndrome: a condition present from birth that affects the development of a kidney and part of the male reproductive tract. Some men have no symptoms and discover it during a scan for another reason.[1,2]
The diagnosis does not automatically mean you are infertile or need surgery. Assessment should consider your symptoms, scan findings and plans for children.
What is Zinner syndrome?
Zinner syndrome, also called Zinner’s syndrome, classically involves three findings on the same side of the body:
An absent kidney, known as renal agenesis.
A fluid-filled cyst in a seminal vesicle.
A blocked or undeveloped ejaculatory duct.[2]
The seminal vesicles are glands behind the bladder that contribute fluid to semen. The ejaculatory ducts carry this fluid and sperm into the urethra during ejaculation.
These structures have linked development before birth through the mesonephric, or Wolffian, duct. A developmental difference can therefore affect both the urinary and reproductive systems. Blocked drainage allows seminal fluid to collect and form a cyst.[2]
What symptoms can it cause?
Symptoms may first become apparent after puberty. They can include:
Pelvic discomfort or pain between the scrotum and anus.
Pain during or after ejaculation.
Blood in the semen.
Passing urine frequently or experiencing burning when urinating.
Recurrent urinary or genital tract infections.
Difficulty conceiving.[1–3]
These symptoms are not specific to Zinner syndrome. Infection, prostatitis and other conditions need consideration before symptoms are attributed to a cyst.
How does it affect ejaculation?
A blocked ejaculatory duct may reduce the amount of semen released or cause painful ejaculation. However, semen volume can remain normal when the other side drains adequately. Normal-looking semen does not reliably show whether sperm numbers or movement are normal.[2,3]
A small ejaculate is also not enough to diagnose an obstruction. The assessment needs to consider other explanations, including incomplete sample collection and semen passing backwards into the bladder, called retrograde ejaculation.[3]
Read more about ejaculatory duct obstruction and TURED.
Can Zinner syndrome cause infertility?
Yes, but fertility varies. Reported findings include low sperm counts, reduced sperm movement and, in some men, no sperm in the ejaculate, called azoospermia. A blockage affecting only one side does not necessarily prevent natural conception.[1,2]
There is no reliable percentage that predicts an individual patient’s fertility. Published estimates come from small, selected groups, often investigated because they already had symptoms or difficulty conceiving.[2]
A semen analysis is a useful starting point, even when fatherhood is a future goal. Abnormal results generally need repeat testing and specialist interpretation. Both partners should be considered when planning fertility treatment.[4]
Before an operation, discuss whether sperm freezing is appropriate. Surgery may improve symptoms without restoring fertility, and there is insufficient evidence that operating on every symptom-free patient prevents future infertility.[2]
Explore male fertility assessment in Brisbane.
How can it affect bladder function?
A seminal vesicle cyst sits close to the bladder. If it enlarges, pressure on the bladder or its outlet can contribute to frequent urination, difficulty emptying or a reduced urinary stream. Urinary infections can also occur.[1]
The urinary symptoms are generally related to pressure or associated inflammation rather than the missing kidney itself. A scan alone cannot establish whether the cyst explains every urinary symptom; bladder emptying and other possible causes may need assessment.
How is Zinner syndrome diagnosed?
Ultrasound may identify an absent kidney and a cyst behind the bladder. MRI can clarify the pelvic anatomy and help distinguish a seminal vesicle cyst from other cysts in this area.[1,2]
Depending on your symptoms and fertility goals, assessment may also include:
Semen analysis, with repeat testing if abnormal.
Examination and selected reproductive hormone tests.
Urine testing for infection.
Urine flow testing and a scan to check residual urine.
Blood pressure, kidney function and urine protein checks.[1,4,5]
Not everyone needs every investigation.
Does Zinner syndrome need treatment?
Monitoring
Observation may be appropriate when there are no troublesome symptoms or concerning findings. Follow-up is tailored to the cyst, kidney health and reproductive plans.[1,2]
Treatment for obstruction or a symptomatic cyst
Selected ejaculatory duct obstructions can be treated through the urethra with transurethral resection of the ejaculatory ducts, or TURED. It is not suitable for every anatomical variation.[4]
An enlarged symptomatic cyst may require a different approach, such as laparoscopic or robotic surgery. Needle drainage can provide relief in selected circumstances, but the cyst may refill.[1,3]
Potential risks depend on the procedure. They include bleeding, infection, recurrent obstruction, injury to nearby structures and changes in ejaculation or fertility. TURED can also allow urine to reflux into the seminal tract and can occasionally worsen sperm findings.[3,4]
Fertility treatment
Options may include treating a suitable obstruction or assisted reproduction. In selected cases, sperm retrieval can provide sperm for IVF with ICSI, where a single sperm is injected into an egg. The decision depends on both partners’ circumstances and preferences.[4]
Most Zinner syndrome evidence comes from case reports and small series. General male infertility guidelines help guide assessment and treatment, but their results should not be presented as guaranteed outcomes for this rare condition.[1,4]
What about living with one kidney?
Many people with one healthy kidney live well. Ongoing care should include blood pressure monitoring and blood and urine tests to check kidney health. Tell your treating clinicians that you have a single kidney when discussing medicines, investigations or surgery.[5]
When should you seek help?
Arrange assessment for persistent painful ejaculation, recurrent infections, urinary difficulties or fertility concerns—particularly if you already know you have one kidney or a seminal vesicle cyst.
Seek urgent medical care if you cannot pass urine, develop fever with flank pain or urinary symptoms, or have severe sudden testicular pain. These symptoms need prompt assessment rather than waiting for a routine appointment.
Assessment in Brisbane, including interstate and international patients
Dr Jack Crozier is a Brisbane urologist and fellowship-trained andrologist whose practice includes male infertility and reproductive tract obstruction.
For an appointment, bring any ultrasound or MRI reports and images, semen analyses, kidney function results and details of previous treatment. Mention whether your main concern is pain, urination, ejaculation or fertility.
Local patients can request a consultation. Interstate patients can use the same form to ask whether an initial telehealth consultation is appropriate. Overseas patients can visit the international patient information page to discuss records review, assessment and travel planning. Confirm the clinical plan and follow-up arrangements before booking travel.
References
Liu T, Li X, Huang L, Li H, Cai K, Jiang J, et al. Zinner syndrome: an updated pooled analysis based on 214 cases from 1999 to 2020: systematic review. Ann Palliat Med. 2021;10(2):2271–2282. doi: 10.21037/apm-20-1997.
Hofmann A, Vauth F, Roesch WH. Zinner syndrome and infertility—a literature review based on a clinical case. Int J Impot Res. 2021;33(2):191–195. doi: 10.1038/s41443-020-00360-0.
Achermann APP, Esteves SC. Diagnosis and management of infertility due to ejaculatory duct obstruction: summary evidence. Int Braz J Urol. 2021;47(4):868–881. Available from: https://pubmed.ncbi.nlm.nih.gov/33566474/
European Association of Urology. EAU guidelines on sexual and reproductive health: male infertility [Internet]. [cited 2026 Nov 6]. Available from: https://uroweb.org/guidelines/sexual-and-reproductive-health/chapter/male-infertility
National Institute of Diabetes and Digestive and Kidney Diseases. Solitary or single-functioning kidney [Internet]. [cited 2026 Nov 6]. Available from: https://www.niddk.nih.gov/health-information/kidney-disease/solitary-kidney
Medical disclaimer
This article provides general education and does not replace an individual medical consultation, diagnosis or treatment plan. Symptoms described here can have several causes. Investigations and treatment depend on your circumstances, and all procedures have potential risks. Improvement in symptoms, semen results or pregnancy outcomes cannot be guaranteed. Seek urgent medical care for severe or rapidly worsening symptoms.
