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

This 2-month-old girl presented with a febrile urinary tract infection. Ultrasonography showed bilateral duplex kidneys with both right upper and lower hydronephrosis (figure 1). There was a very dilated tortuous right upper pole ureter (figure 2). There was left upper pole hydronephrosis as well (figure 3) and the left ureter was also dilated and tortuous (figure 4). During voiding cystourethrography, the catheter entered the left upper pole ureter (figure 5). Contrast was instilled and showed a small sphincteric ureterocele and the dilated upper pole calyces (figure 6, 7). The opening of the ureterocele was at the junction of the bladder neck and the urethra (figure 8). There was no left lower pole or right sided reflux. An IVP with a catheter draining the left upper pole showed bilateral duplex kidneys (figure 9). The tiny ureterocele was seen at the base of the bladder on its left side. The lower pole on each side was normal. On the left, there was fair visualization of the slightly dilated upper pole. On the right, there was no visualization of the upper pole. The right lower pole ureter was tortuous as it wrapped around its dilated upper pole mate. Thus, the final diagnosis was bilateral duplex kidneys with bilateral upper pole obstruction. The left upper pole ureter ended in a sphincteric ureterocele. The right upper pole ureter was ectopic and obstructed and there was no ureterocele.