This two-week old male infant presented with an antenatal history of right renal pelvis dilatation. The ultrasound image above shows a rounded cystic structure within the bladder, to the right of midline. Some echogenic debris can be seen within the structure. The appearance is characteristic of a ureterocoele.

A ureterocoele is a congenital dilatation of the intramucosal portion of the ureter. A ureterocoele may be simple or ectopic. Ectopic ureterocoele is almost always associated with a duplicated collecting system, and is more common than the simple type. Ureterocoele may be associated with either reflux or obstruction. A ureterocoele may prolapse into the bladder neck and cause bladder outlet obstruction. The prognosis of ureterocoele is related to the degree of associated reflux or obstruction.

Reference: Donnelly LF, et al. Pediatrics: Top 100 Diagnoses Amirsys 2002

Credit: Dr Laughlin Dawes