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Purpose: We determined the role of magnetic resonance imaging (MRI) in symptomatic children with clinically suspected and radiologically occult dysplastic renal moieties and ectopic ureters., Materials and Methods: We reviewed clinical, imaging, cystoscopic, surgical and histological findings in 6 symptomatic children 1 to 15 years old with dysplastic renal moieties., Results: After multiple conventional imaging studies failed to delineate urinary tract anatomy MRI provided detailed multiplanar images of dysplastic renal moieties that were diagnostic and predictive of subsequent intraoperative findings. Dysplastic upper pole moieties identified in 4 children were associated with ectopic ureters inserting into the vagina, prostatic urethra, bladder neck and bladder neck ureterocele in each. A solitary kidney with contralateral blind-ending ectopic ureters inserted into the bladder base in 2 cases. Pelvic cystic structures visualized by ultrasound in 3 patients were tortuous distal ureters on MRI. MRI specifically identified ureteral insertion sites that were not evident in 3 of the 5 patients who underwent cystoscopy., Conclusions: MRI may facilitate diagnosis, guide cystoscopy and aid in preoperative planning in children with poorly functioning renal moieties and ectopic ureters.

Objective: The prognosis in patients with posterior urethral valves (PUV) is related to the degree of renal insufficiency. Urinary ascites or urinoma, congenital bladder diverticula, or severe unilateral vesicoureteral reflux has been associated with protected renal function. We present clinical and imaging findings in eight patients with PUV and unilateral reflux who have preserved renal function. Initial and follow-up sonography, voiding cystourethrography, and nuclear imaging were reviewed and compared with long-term serum creatinine levels., Conclusion: All eight patients had normal renal function on long-term follow-up, suggesting that unilateral reflux, which occurs in as many as 35% of boys with PUV, is associated with protected renal function. Although early nephrectomy of the refluxing unit has been advocated for patients with PUV and unilateral reflux into a dysplastic kidney (the vesicoureteral reflux and renal dysplasia syndrome), we found that significant renal function may be present in the refluxing kidney and that function may even increase with time. Most of these patients did well without nephrectomy. Therefore, a sufficient interval should elapse before nephrectomy is considered in these patients.

We report on a neonate with a history of failure to thrive who had a large right abdominal mass. Renal ultrasound showed a large cystic mass that arose from the upper pole of the hydronephrotic right kidney. Preoperative antegrade pyelography confirmed that the mass communicated with 1 kidney. Further evaluation revealed no communication of the ureter with the bladder or vagina. Exploratory surgery identified the mass and intraoperative pyelography revealed no communication with the bladder. After resection of the mass and nephrostomy placement, reimplantation of the right ureter demonstrated complete atresia of the distal right ureter. Preservation of the remaining renal parenchyma was possible, because the functioning lower pole collecting system communicated with the cystic mass that arose from the upper pole.

Multicystic kidney was first described in a 7-month-old child. Some physicians advocate nephrectomy in such cases, while others have questioned this procedure. In 1986 the American Academy of Pediatrics, Section on Urology established the Multicystic Kidney Registry to identify and follow patients with multicystic kidney disease. To date 441 patients have been registered, of whom 260 were managed nonoperatively. Based on followup of these patients no kidneys were removed for hypertension, infection, pain or tumor development. Long-term findings show that multicystic kidney disease may take as long as 20 years to resolve, and followup testing will be necessary.

Eighty-one cases of multicystic dysplastic kidney (MCDK) in children were diagnosed over the past 11 years at the authors' institution: 25 children had their kidneys surgically removed, eight with bilateral total involvement died, and 48 underwent serial follow-up ultrasonography (US) of their kidneys. Follow-up included 193 serial ultrasound (US) studies (mean, four per patient) for a total of 1,468 months (mean, 30.5 months). In the 48 patients followed up, 32 (67%) kidneys showed a decrease in size, nine (19%) showed no change, and five (10%) increased in size, and in two (4%), a change in size could not be determined. In seven of the 48 (15%) children, the MCDKs decreased in size, and, at follow-up US, no renal tissue could be found. In those patients in whom MCDKs decreased in size. Serial US characteristics changed from predominantly an enlarged cystic structure to a small dysplastic or absent kidney. Two of the five kidneys that increased in size were surgically removed, and MCDK was pathologically confirmed. A nonsurgical approach to the treatment of patients with MCDK is supported by this study.