Zinner syndrome: unilateral renal agenesis with unique findings in a 19-year-old patient from Pakistan - a case report with literature review.

Introduction and importance: Zinner syndrome (ZS), a rare congenital defect, involves three specific conditions on one side of the body: renal agenesis (missing one kidney), cyst of the seminal vesicle, and ejaculatory duct obstruction. It arises from developmental irregularities in the mesonephric duct. MRI is the definitive diagnostic tool. Its rarity in young patients underscores the uniqueness of our case. Case presentation: A male student, 19 years of age, presented with dysuria, urethral pain, a burning sensation during urination, and painful nocturnal emissions for two years. A physical examination showed no abnormalities, with normal vital signs and laboratory results. Imaging showed right-sided renal agenesis, left kidney hypertrophy, a cyst near the right seminal vesicle, and ejaculatory duct obstruction, with a suspected hemorrhagic seminal vesicle cyst. Clinical discussion: ZS is a rare congenital condition frequently without symptoms but may present with lower urinary and genital tract symptoms in the second or third decade. A review of 200 cases showed a 0.046% incidence rate, with right-sided abnormalities more common. Seminal vesicle cysts are the most frequent cystic lesions. Diagnosis typically involves MRI, though CT and ultrasound were used historically. Management options include surgery, aspiration, or observation. Conservative management was successful for our patient, with symptoms improving over time. Conclusions: ZS is an extremely rare condition with unilateral agenesis of the kidney, an ipsilateral cyst of the seminal vesicle, and obstruction of the ejaculatory duct. Early diagnosis and heightened awareness are essential for effective treatment and better outcomes in affected patients due to its rarity.