ureterocele is a congenital urinary abnormality characterized by the presence of an intrabladder hernia or cystic ballooning of the lower end of a ureter lying between the mucosa and muscle of the bladder . the abnormality leads to urinary retention and recurrent urinary tract infection ( uti ) , which can cause irreversible damage to the kidney . this abnormality can be suspected in the fetus by antenatal ultrasonography ( usg ) and confirmed by other x - ray investigations after birth . the incidence of ureterocele is variable with the highest rate of 1:500 and it is generally found in females with duplex system association ( 95% ) . ureteroceles can have different clinical presentations , such as antenatal hydronephrosis , uti , vesicoureteral reflux ( vur ) , bladder outlet obstruction , prolapsed urethral mass , etc . usg and voiding cystourethrography ( vcug ) are essential initial procedures for a child suspected of having a ureteral anomaly . a 5-year - old female child was referred to our department for tc - diethylene triamine pentaacetic acid ( dtpa ) scan . she was a follow - up case of right - sided hydroureteronephrosis with pyonephrosis with percutaneous tube ( pcn ) insertion done on the right side . patient 's blood urea and serum creatinine were 29 and 1.3 mg / dl , respectively . usg of the abdomen revealed left - sided mild hydroureteronephrosis and gross enlargement of the right kidney , reaching up to lower abdomen with dilated pelvis and ureter . the child was referred for evaluation of glomerular filtration rate and excretory function of kidneys . tc - dtpa scan was done in our department with right pcn tube in situ . pcn tube was clamped during the acquisition of dynamic and prevoid static image and clamp released thereafter . on tc - dtpa scan , left kidney showed good perfusion and adequate cortical radiotracer concentration followed by good drainage into dilated ureter . right ureter and right pelvicalyceal system ( pcs ) were visualized in the postvoid image ( indirect evidence of vur ) [ figure 2b , thin arrow ] . retention of radiotracer was noted in dilated pcs and dilated ureter in delayed static images acquired till 4 h [ figure 2c and d ] . faint visualization of radiotracer was noted through the pcn tube after removal of clamp [ figure 2b , bold arrow ] . a large photopenia was noted in the suprapubic region in the urinary bladder ( ub ) during dynamic [ figure 1 ] as well as delayed static images acquired till 4 h [ figure 2a  d ] . an usg of the abdomen was done in the radiology department of our hospital to find out the cause of this persistent photopenia in the ub . usg of the abdomen showed evidence of left - sided mild hydroureteronephrosis and grossly enlarged hydronephrotic right kidney with dilated right ureter and an intracystic ureterocele arising from the right side [ figure 3a and b ] . perfusion and dynamic images of 99mtc - diethylene triamine pentaacetic acid scan scintigraphy , posterior view with percutaneous clamp in situ , showing good perfusion and adequate cortical function and good drainage of left kidney . photopenia noted in the urinary bladder ( bold arrow ) ( a ) prevoid static image with right pcn clamp in situ . right ureter and right pelvicalyceal system visualization is noted suggesting indirect evidence of vesico - ureteric reflux ( thin arrow ) . ( c and d ) 3 and 4 h delayed static images showing persistent photopenia in the urinary bladder ( arrow marked ) ( a and b ) ultrasonography images depicting right ureterocele within the urinary bladder ( ub ) and dilated distal right ureter according to literature , 90% of the patients with ureterocele are diagnosed before the age of 3 years . most of the patients with ureterocele are classically diagnosed during the investigation for uti , asymptomatic hydronephrosis , and abdominal mass . although the age of diagnosis is decreasing , uti is still the most common clinical presentation of ureterocele in 50% of the patients promoting physician to make the thorough evaluation of the urinary system . the whole nephronourinary system could have already been negatively affected at the time of diagnosis . in our case , usg is an easy method to perform , noninvasive , and probably the best imaging modality for making the diagnosis . reflux can occur in the ipsilateral lower pole in almost half of the patients , but the contralateral system is also affected at a rate of 25% . the tc - dimercapto succinic acid ( dmsa ) scan should be undertaken routinely to assess the distribution of function in the duplex kidney and for detecting and follow - up of scarred tissue and nonfunctioning upper poles in cases of ureterocele . did a study on pediatric ureteroceles in 19 patients , on the diagnosis , management and treatment options . vcug was able to detect vur in 13 out of 17 patients ( 33% ) . dmsa scintigraphy showed ipsilateral renal scarring and nonfunctioning upper pole images in 7 out of 13 patients . computed tomography and mag3 scintigraphy did a study on the management of 36 patients with varied presentation of complicated ureteroceles . usg , micturating cystourethrogram , isotope renogram were done preoperatively in all the babies . in one of the cases , initial usg was unable to detect ureterocele in most of the cases in this study . they said that unless the usg is done in well - hydrated , cooperative patient , ureterocele is likely to be missed on usg . hence , an intravenous pyelogram , radioisotope renogram , and micturating cystourethrogram are invaluable in the complete understanding of ureterocele . in our patient also , the diagnosis of ureterocele was missed on initial usg . photopenia was noted in the ub on our scan , and this prompted us to investigate the patient further . possible causes for photopenic defects in the ub on nuclear scintigraphic studies include bladder papilloma , bladder polyp , carcinoma bladder , bladder calculus , foreign body in ub , intravesical ureterocele , etc . repeat usg revealed the cause of photopenia in ub in our case to be an intravesical ureterocele . on reviewing the literature we found that tc - dtpa scan is useful in the evaluation of renal function in patient with known ureteroceles . however , in our case on finding the photopenia in the ub on tc - dtpa scan , intravesical ureterocele was detected on usg .
ureterocele is a common ureteric anomaly detected in pediatric population . 
 ureterocele diagnosis and evaluation need a variety of radiological methods . 
 we report a case of 5-year - old female child sent for 99mtc - diethylene triamine pentaacetic acid scan for evaluation of glomerular filtration rate and excretory function of kidneys in view of right - sided hydroureteronephrosis and pyonephrosis with percutaneous tube in situ . 
 incidental photopenia was noted in the urinary bladder . 
 on ultrasonography of abdomen cause of this photopenia was found to be an intravesical ureterocele .