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

This eight-year-old boy had straining to avoid hematuria. An ultrasound exam showed a normal right kidney, a left single system kidney with mild hydronephrosis, and a ureterocele in the bladder. A VCUG showed that when the bladder filled, the ureterocele was in the bladder (Fig 1); but when he voided, the ureterocle prolapsed into the urethra (Fig 2). He underwent excision of the ureterocele and reimplantation of the ureter. A post-op VCUG was normal, as was the post-op ultrasound exam.