Zinner Syndrome Variant Diagnosed With Contralateral Neuroendocrine Tumor
Zinner syndrome—a rare congenital urogenital malformation involving unilateral renal agenesis, seminal vesicle anomalies, and ejaculatory duct obstruction—has been linked to a contralateral neuroendocrine tumor in a 26-year-old man, according to a case study published in medical literature. The patient, measuring 183 cm and weighing 73 kg, presented with unusual urinary urgency occurring two to 10 minutes after complete bladder emptying, alongside postvoid dribbling and suspected retrograde ejaculation.
According to clinical findings, the patient’s congenital condition involved agenesis of the left kidney, left seminal vesicle, and left ejaculatory duct. While Zinner syndrome typically stems from early maldevelopment of the Wolffian duct during the first trimester between the 4th and 13th weeks of gestation, affected individuals often remain asymptomatic until sexual activity triggers seminal vesicle dilation and cyst formation. In this specific case, initial histological examination of a urethral biopsy suggested invasive urothelial carcinoma, prompting a recommendation for radical prostatectomy and cystectomy.
Diagnostic Revision and Advanced Imaging Findings
Seeking a second opinion, the patient underwent expanded blood tests and imaging that ultimately shifted the diagnosis. Laboratory results showed elevated chromogranin A levels ranging from 128.5 ng/mL to 407 ng/mL, while prostate-specific antigen and neuron-specific enolase levels remained within normal limits. Magnetic resonance imaging of the bladder revealed a mildly contrast-enhancing mass in the right seminal vesicle infiltrating the adjacent prostate, alongside an enlarged lymph node below the right iliac bifurcation.
Gallium-68 PET-CT imaging demonstrated increased SSTR expression in the right seminal vesicle with an SUVmax of 12.8. Additional computed tomography scans of the lungs and abdomen, as well as gastroscopy and colonoscopy, ruled out primary gastrointestinal or bronchial tumors. Following a second biopsy, pathologists revised the diagnosis to a well-differentiated neuroendocrine tumor originating from the right seminal vesicle or prostate, exhibiting a low Ki-67 proliferation index of 3%.
Surgical Intervention and Postoperative Recovery
The patient underwent a robot-assisted radical prostatectomy with parailiacal lymph node dissection. Subsequent histological analysis confirmed a well-differentiated neuroendocrine tumor of the prostate and right seminal vesicle, featuring tumor infiltration of the right pelvic wall and metastasis to one of three lymph nodes near the right external iliac artery. Comprehensive genomic profiling via the “TruSight Oncology 500 DNA” test revealed a low tumor mutational burden of 0.79 mutations per megabase and microsatellite stability.
Following the seven-hour general anesthesia procedure, the patient experienced transient postoperative complications, including bilateral foot numbness and absent Achilles tendon reflexes. Neurological evaluation attributed these symptoms to sural nerve compression caused by slightly persistent knee flexion during surgery. Postoperatively, the patient’s chromogranin A levels normalized, and tumor board consultations resulted in a preliminary decision to omit adjuvant chemotherapy or radiotherapy.
Comparative Presentation: A Variant with Refractory Hematospermia
In a separate clinical report documented in medical archives via ncbi.nlm.nih.gov, another rare variant of Zinner syndrome presented in a 27-year-old man suffering from chronic hematospermia, painful ejaculation, and primary infertility. Transrectal ultrasonography and pelvic MRI in that case demonstrated a left seminal vesicle cyst, left renal agenesis, and contralateral right seminal vesicle hypoplasia. Unlike the 26-year-old patient requiring radical prostatectomy for a neuroendocrine tumor, the 27-year-old patient was managed successfully with transurethral resection of the ejaculatory duct guided by methylene blue vasography, resulting in the complete resolution of hematospermia and painful ejaculation at a two-month follow-up.
Frequently Asked Questions
What are the primary characteristics of Zinner syndrome?
According to medical literature, Zinner syndrome is a rare congenital anomaly characterized by a classic triad of unilateral renal agenesis, an ipsilateral seminal vesicle cyst or seminal vesicle agenesis, and ipsilateral ejaculatory duct obstruction.
Why was the initial cancer diagnosis revised in this patient?
Initial biopsies suggested invasive urothelial carcinoma, but elevated chromogranin A levels, specialized PET-CT imaging, and immunohistochemical marker analysis during a second review led specialists to correctly identify a well-differentiated neuroendocrine tumor.
Can Zinner syndrome cause infertility?
Yes. According to clinical data, Zinner syndrome accounts for infertility in approximately half of affected patients due to obstruction and structural abnormalities within the urogenital tract.
Pro Tip: Patients presenting with persistent lower urinary tract symptoms, hematospermia, or localized urogenital anomalies should undergo thorough imaging, including pelvic MRI and specialized biomarker testing, to rule out rare oncological complications.
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