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

This 5-year-old boy presented with day and night wetting and asymptomatic bacteriuria. Ultrasound showed what appeared to be two ureteroceles within the bladder (fig. 1). Most of the time, when two ureteroceles are seen, it is really a single bilobed ureterocele. Ultrasonography of the kidneys showed what appeared to be a normal right kidney with a single collecting system (fig. 2) and a left duplex kidney with upper pole uretero hydronephrosis (fig. 3) It was assumed that the ureterocele was at the end of the left upper pole ureter. A VCUG showed the ureterocele. An IVP showed a left duplex kidney with a normal lower pole and hydroureteronephrosis of the upper pole (fig. 4) The ureter was obstucted at its distal end. The bladder filled with contrast material but the ureterocele did not fill, thus signifying that it was not at the end of the left upper pole ureter. The left lower pole was normal. On the right, there appeared to be a normal single system kidney. However, the presence of the ureterocele, filled with non-opaque urine in the bladder, meant that the right kidney had a double collecting system and there was an invisible, nondilated, nonfunctioning right upper pole with a tiny ureter ending in the ureterocele. What appeared to be a single collecting system on the right was really the lower pole. At the time of cystoscopy, the ureterocele was injected. The tiny right upper pole ureter ended blindly at the level of the kidney (fig. 5)