An intravenous urogram shows a rounded filling defect at the distal end of the right ureter with a surrounding radiolucent halo, producing a spring-onion or cobra head appearance. The diagnosis is:

• A Ureterocele ✓
• B Transitional cell carcinoma of the distal ureter
• C Ureteric calculus impacted at the vesicoureteric junction
• D Pseudodiverticulum of the ureter

Explanation

A simple ureterocele is a cystic dilatation of the terminal intravesical ureter due to congenital stenosis of the vesicoureteric orifice. On urography it appears as a bulbous contrast-filled dilated distal ureter outlined by a thin radiolucent wall against bladder contrast, giving the cobra head or spring-onion sign. A tumour or calculus produces an irregular filling defect without a smooth lucent rim, and pseudodiverticula are outpouchings of the ureteric wall, not terminal bulbs.

Reference: Grainger and Allison Diagnostic Radiology, 7th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.