Screening for Zinner Syndrome in Patients With a Congenitally Solitary Kidney: Lessons Learned.

Purpose: We determined if serial screening ultrasounds are beneficial in evaluating for the development of Zinner syndrome in males with a congenital solitary kidney.
Materials and Methods: All patients included had their congenital solitary kidney diagnosed at <20 years of age and had to be ≥20 at their last visit. Individuals were seen annually, with pelvic ultrasounds to screen for mesonephric duct cysts obtained at birth and every year of age, divisible by 5.
Results: At a median follow-up of 38 years of age (range 20-57), 17% (20/121) developed Zinner syndrome, with 60% (12/20) developing clinical symptoms. The yield for screening ultrasound studies was significantly higher in patients ≤20 years of age at 3.5% (12/340), compared to 0.33% (1/296) in patients >20 years of age ( P = .004). Serial ultrasounds reveal the onset of lower urinary tract and cyst-related pain symptoms are associated with the growth of the seminal vesicle cyst to ≥5 cm ( P = .0198). Of symptomatic patients, 75% (8/12) had abnormal uroflows. Complete urodynamic studies revealed findings consistent with bladder outlet obstruction in 38% (3/8), equivocal for obstruction in 24% (2/8), and detrusor underactivity in 38% (3/8). Cyst excision effectively resolved voiding symptoms that were obstructive in etiology but failed to resolve symptoms in patients with detrusor underactivity.
Conclusions: Serial ultrasound evaluations reveal that cyst growth to ≥5 cm in size is highly related to the onset of clinical symptoms, with the resolution of voiding symptoms by cyst excision directly associated with urodynamic findings.