Lower urinary tract abnormalities in children with multicystic dysplastic kidney

PURPOSE: To determine the nature and frequency of associated structural abnormalities of the lower urinary tract in children with multicystic dysplastic kidney. MATERIALS AND METHODS: The authors reviewed imaging findings from studies in 59 children with unilateral multicystic dysplastic kidney. All patients had undergone renal ultrasonography (US), renal scintigraphy, and voiding cystourethrography. The diagnosis was based on characteristic imaging findings (echogenic, cystic kidney at US that did not function at scintigraphy). RESULTS: Nineteen (32%) patients had one or more abnormalities of the lower urinary tract. Vesicoureteral reflux was most common (15 patients). Reflux occurred into the contralateral ureter in 12 patients and the ipsilateral atretic ureter in five (two had bilateral reflux). Four patients had ectopic ureters: Three cases were ipsilateral and inserted into the prostatic urethra (two cases, both with reflux) or into the seminal vesicle (one case); one case was contralateral and inserted into the bladder neck. Four patients had an ipsilateral obstructed single-system ureterocele. Four patients had bladder diverticula. Other abnormalities included hypospadias, opacification of a small utricle (not in the patient with hypospadias), ejaculatory duct reflux, internal urachal sinus, and lipomeningocele with a neurogenic bladder. CONCLUSION: Abnormalities of the lower urinary tract are common in children with unilateral multicystic dysplastic kidney. Voiding cystourethrography should be performed routinely in this population.