Description: Clip at 26 weeks gestation of a female fetus showing bilateral “duplex kidney” where each kidney has two separate pelvicalyceal systems and the urinary bladder shows intravesical ureterocele.
This finding is twice as common in females as males, in one fifth of cases the condition is bilateral as in this case.
- The left kidney shows signs of Complete Duplication where there are double ureters draining separately into the bladder. This is evidenced by the hydronephrotic upper renal pelvis compared to the lower renal pelvis on the left side, which suggests some form of obstruction of its draining ureter. According to the Meyer Weigert Law the two ureteral orifices in the bladder are characteristically inverted in relation to the collecting systems they drain. The orifice of the lower pole ureter occupies the more cranial and lateral position and upper pole ureter . The upper pole obstructs and the lower pole refluxes. The caudal orifice of the upper pole ureter is often stenotic and results in marked dilatation of the upper renal collecting system, hydronephrosis and ureterocele.
- Images of the bladder show intravesical ureterocele which is a ballooning of the terminal ureter as it enters the bladder, this ureterocele is mostly the obstructed distal end of the ureter draining the hydronephrotic upper pole of the left kidney.
- The right kidney however shows almost equal size of the upper and lower poles. This suggests no obstruction of the ureteric drainage not a complete duplication as the case of the left kidney.
Other anomalies of the genital tract as well as presence of an ectopic ureter draining into an abnormal site in the genitourinary tract should be investigated following birth.