Zinner Syndrome Associated With a Neuroendocrine Tumor of the Prostate Gland and Contralateral Seminal Vesicle: A Case Report

Zinner syndrome is a rare congenital malformation of the urogenital system characterized by the triad of unilateral renal agenesis, ipsilateral seminal vesicle cyst, and ipsilateral ejaculatory duct obstruction.A variant of Zinner syndrome is present when, instead of a seminal vesicle cyst, there is agenesis of the ipsilateral seminal vesicle.Although Zinner syndrome has been associated with urogenital neoplasms in some cases, to our knowledge, no case of a patient with Zinner syndrome and a contralateral neuroendocrine tumor (NET) has been previously described.The patient is a 26-year-old man who developed urinary retention due to a tumor of the right seminal vesicle infiltrating the prostate and obstructing the prostatic urethra.Abdominal and bladder MRI showed dysgenesis of the left kidney, seminal vesicle, and ejaculatory duct, as well as a mildly contrast-enhancing mass of the right seminal vesicle infiltrating the adjacent prostate.Gallium-68 PET-CT showed increased somatostatin receptor (SSTR) expression in the right seminal vesicle.Histologically, it was a welldifferentiated NET with infiltrates of epithelial tumor cells that were positive for chromogranin, synaptophysin, and CD56.Chromogranin was also increased in the serum.The patient underwent radical prostatectomy, and it was decided not to proceed with chemotherapy or radiotherapy.Zinner syndrome may be associated with a contralateral NET of the genitourinary tract.Therefore, patients with Zinner syndrome should be regularly followed up to avoid overlooking a co-occurring malignancy.