Ultrasound Case 073

Image 1: Oblique just off longitudinal view of the distal right ureter and bladder.

There is a thin walled simple unilateral ureterocele. It dilates with each ureteric contraction and then slowly shrinks as urine is released into the bladder through the narrowed outlet. This appearance is known as a cobra head or spring onion when seen on IVP. On ultrasound the ureteric jet gives the appearance of a spitting cobra, a new name I have just decided upon!

Image 2: Transverse view of the bladder at the level of ureteric orifices at the lateral margin of the trigone.

The thin walled ureterocele is again seen rising and shrinking with each ureteric jet and its release. There is dilation of the ureter.

Ureterocele – a spitting cobra!

Ureteroceles are cystic dilatations of the intravesical portion of the distal ureter. It is thought a congenital or occasionally an acquired stenosis obstructs the meatus and resultant ballooning of the distal ureter occurs. This may occur in a single or more commonly (75%) a duplex ureteric system.

When there is a single ureter a ureterocele it is known as a simple ureterocele. When it is a duplex system with an ectopic ureteric insertion, it is known as an ectopic ureterocele. This occurs in the more medially and inferiorly positioned VUJ of the upper moeity which often develops hyronephrosis and hydroureter. The lower pole moiety which inserts higher and more laterally is prone to reflux. This distal ureteric insertion pattern and propensity to upper moiety obstruction and lower moiety reflux is known as the Weigert-Meyer rule.

• Berrocal T, López-Pereira P, Arjonilla A, Gutiérrez J. Anomalies of the Distal Ureter, Bladder, and Urethra in Children: Embryologic, Radiologic, and Pathologic Features. Radiographics. 2002 Sep-Oct;22(5):1139-64.
• Shah V, Abdrabou A. Ectopic ureter. Radiopaedia
• Carl Weigert (1845-1904)
• Robert Meyer (1864 – 1947)
• Weigert-Meyer rule