Zinner Syndrome: An Incidental Finding.

The authors present a case of a 56-year-old man referred to the urology clinic after an incidental finding on abdominal ultrasound. Imaging revealed an oval cystic lesion adjacent to the right seminal vesicle, initially interpreted as a probable atrophic ectopic kidney. Magnetic resonance imaging (MRI) confirmed right renal agenesis, ipsilateral seminal vesicle cyst, and probable ejaculatory duct obstruction. A small intralesional nodular component was identified. The patient was asymptomatic, with preserved renal function and a prostate-specific antigen of 0.9 ng/mL. A transrectal biopsy was performed due to the suspicious nodule. Histopathological analysis demonstrated seminal vesicle/ejaculatory duct tissue with stromal edema lined by a single-layer cuboidal epithelium (CK7+, 34BE12+, PAX8+, PSA-, CK20-) and low Ki-67 (<1%), with no evidence of malignancy. Conservative management with imaging surveillance was adopted. Follow-up MRI at six-month intervals showed lesion stability. The patient remains asymptomatic, emphasizing the role of imaging in the diagnosis, assessment, and monitoring of asymptomatic Zinner syndrome.