Robert L. Lebowitz, M.D. Children' s Hospital, Harvard Medical School Boston, Massachusetts

This boy was found to have hydronephrosis in utero. Evaluation after delivery began with an ultrasound exam that showed a normal left kidney. On the right, there was a duplex kidney with both upper and lower pole hydronephrosis(Figure 1). There was a large ureterocele in the bladder(Figure 2). A voiding cystourethrogram showed a large intravesical ureterocele that neither prolapsed nor everted. There was right lower pole reflux into a tortuous ureter. (Figure 3). Ureteral tortusity was due to the fact that the lower pole ureter was wrapped around its dilated, invisible upper pole mate. There was mild extrinsic UPJ obstruction of the lower moiety (shown on the drainage film after the VCUG) (Figure 4) due to crossing of the lower UPJ by the dilated upper pole ureter. An IVP (Figure 5) again showed the ureterocele, the normal left kidney, the mildly dilated lower pole on the right that functioned well and nonvisualization of the right upper pole. The unusual thing about this example is that ectopic ureteroceles in duplex kidneys are much more common in girls. He is to undergo endoscopic incision of the ureterocele in the hope that as the upper pole decompresses, the lower UP obstruction will disappear and perhaps, even the lower reflux will resolve.