This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pediatrics
A 6 year old girl presents with Recurrent E.coli infection in urine. Ultrasound of abdomen shows Hydroureter and Hydronephrosis. Micturating cysto – urethrogram shows filling defect in urinary bladder. The likely diagnosis is – 
Select and explain. 
A. Sacrococcygeal Teratoma, B. Vesicoureteric Reflux – grade II, C. Duplication of Ureter, D. Ureterocele
D: Ureterocele
Answer: D: Ureterocele 
Explanation: IVP in ureterocele usually shows a round filling defect, sometimes large, in the bladder corresponding to the ureterocele, and characteristic finding of duplication of the collecting system (ureteroceles are nearly always associated with ureteral duplication)
Ureterocele :

Is a cystic dilatation of the terminal ureter, and is obstructive because of a pinpoint ureteral orifice.
It is more common in females
Affected children often are discovered by prenatal sonography or during an investigation of UTI (IVP)
Treatment : o transurethral incision of ureterocele : effectively relieves the obstruction but it may result in V.U.R. necessitating ureteral reimplantation later, or
' open excision of ureterocele and reimplantation 'as primary management'. About other options
An isolated VUR or Duplication of ureter do not explain the filing defect in the bladder.
Sacrococcygeal Teratoma :
The most common presentation here is with an abnormal, obvious protruding mass from the sacral area. Out of the 4 varieties known, only Type IV which contributes 9.8 % ie entirely pre-sacral and not visible externally (90.8% tumors are visible externally).
Bladder and Rectum may be displaced anteriorly but a filling defect is not characteristic as in ureterocele.
Ureters may be partially obstructed resulting in hydro-ureter and hydronephrosis.