extrarenal calyces are rare anomalies of the upper urinary tract . only 20 cases were reported so far in the literature .
the rarity of this anomaly and the complexity of possible associated anomalies often makes the preoperative diagnosis difficult .
they are known to be associated with other anomalies , including bifid kidney and renal dysplasia . to the best of our knowledge ,
only 3 cases have been reported in the literature wherein , it was associated with pelviureteric junction obstruction ( pujo).[24 ] when associated , management options depend on the renal function and presenting symptoms . herein , we are reporting a case where routine preoperative imaging did not throw any light on the diagnosis and was an intraoperative surprise .
a 9-year - old male child presented to us with complaints of pain in the left flank for 1 month .
an ultrasound of the abdomen showed severe hydronephrosis of the left kidney with a parenchymal thickness of 2 mm with upper ureteric dilation .
a radionuclide scan showed a poorly functioning left kidney with a split renal function of 7% with obstructed curves .
an ante grade dye study was done , which showed significant stasis in the hydronephrotic kidney and the ureter was not visualized .
intraoperatively , a large dilated kidney with papery thin cortex was found with 5 pseudopodia - like projections ( extrarenal calyces ) arising from it and connected to the pelvis ; pujo was noted .
the rest of the ureter appeared normal . in view of the complex nature of the lesion and poorly functioning kidney , a right nephroureterectomy was performed [ figure 1 ] .
the presence of extrarenal calyces is a very rare anomaly of the upper urinary tract that was first described in 1925 .
a few cases were reported in the literature and the exact etiology of this condition is unclear .
it has been hypothesized that the anomaly could be due to a disparity resulting from slow development of the metanephric tissue or to a relatively rapid development of the ureteric bud . a kidney with extrarenal calyces is usually associated with other anomalies , such as bifid kidney , renal ectopia , horseshoe kidney , and renal dysplasia .
it might be an incidental finding diagnosed at autopsy or may present with complications , such as hydronephrosis secondary to associated pujo , as in our case . because the incidence of this anomaly is quite low and the clinical presentation is very similar to classic pujo , a high degree of suspicion should be kept , especially when preoperative radiologic findings are not classical and show distorted calyceal appearance on preoperative imaging studies .
this would safeguard against inadvertent injury of the calyces when operating on a well - functioning kidney .
but , when they are associated with complications , such as pujo , as in our case , the management is not standardized .
( 2006 ) mentioned the successful management of pujo associated with extrarenal calyces in a pelvic kidney using transperitoneal laparoscopic reconstruction .
the management options may include the following : ( 1 ) to do a classic pyeloplasty and follow the patient , risking failure of pyeloplasty and recurrent urinary tract infection ( uti ) ( as was done in the previous case ) ; ( 2 ) to resect the pelvis and do a ureterocalicostomy with fusion of the calyces ( again associated with extensive dissection and suturing ) ; or ( 3 ) to go ahead with a single - stage nephroureterectomy , thereby preventing the child from further recurrent uti .
the management strategies are controversial and should be decided on individual merits and surgeon competence . however , in kidneys with well - preserved function , a renal sparing procedure is worth attempting .
 extrarenal calyces are one of the rare renal anomalies associated with the collecting system . 
 their association with renal ectopia or horse shoe kidney is known . 
 but , here in , we are reporting an intraoperative surprise , where extrarenal calyces were associated with pelviureteric junction obstruction and routine preoperative imaging did not show any light on the diagnosis . 
INTRODUCTION
CASE REPORT
DISCUSSION