Contralateral renal abnormalities in multicystic-dysplastic kidney disease.

Multicystic-dysplastic kidney (MCDK) disease has been associated with contralateral genitourinary tract abnormalities; however, neither the nature nor the prevalence of the contralateral renal lesion has been delineated. We retrospectively studied patients with MCDK disease to determine the prevalence of contralateral renal abnormalities and of other urologic anomalies. Forty-nine patients, ranging in age from neonates to 6 years, were examined by renal ultrasonography, excretory urography or nuclear medicine scanning, and voiding cystourethrography; 51% of the patients had an associated urologic abnormality. The abnormality was contralateral to the MCDK in 19 patients (39%), ipsilateral in 3 patients (6%), and involved the bladder wall in 3 patients (6%). The most common contralateral genitourinary tract abnormality was vesicoureteral reflux (18%) followed by ureteropelvic junction obstruction (12%). We conclude that urologic anomalies are common in patients with MCDK disease; contralateral vesicoureteral reflux is the most common abnormality identified.