Cystic, balloon-like dilatation of intramural portion of distal ureter bulging into bladder

Orthotopic ureterocele (less common) : Normal insertion at trigone and otherwise normal ureter

Ectopic ureterocele (more common) : Inserts below trigone

Duplicated collecting system in 80%

Ectopic: 50% in bladder and 50% in posterior urethra; 10% bilateral

Thin-walled, cystic intravesical mass continuous with distal ureter

Changes in size with degree of ureteral dilation

Dilated ureter in ectopic lower moiety, changes in size with degree of ureteral dilation

Obtain images when bladder is reasonably full

IVP/cystogram

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  Orthotopic ureterocele: Cobra head deformity

  
  
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  Drooping lily sign: Displacement of reflux opacified lower pole moiety by dilated upper pole moiety

  
  
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  Images during early bladder filling; overfilling may collapse, obscure, or invert low-pressure ureterocele

T2W MR

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  Superior to demonstrate ectopic ureter extending from poorly functioning moiety invisible on other imaging

Single system ectopic ureteroceles: Associated with cardiac and genital anomalies

Complete duplicated system: Commonly upper moiety ureter associated with ureterocele

Look for ureterocele in reasonably full bladder if duplex renal system detected

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  Ureteroceles can be missed if bladder is empty and ureterocele is collapsed

Look for ureteroceles at ureterovesical junction, which should always be included in bladder protocol

Ureteroceles are highly dynamic and will “inflate” and “deflate” during peristaltic activity of ureter; adequate scanning time is required to visualize “inflation” stage of ureterocele