Pediatric Ureteropelvic Junction Obstruction

  • Etiology: intrinsic narrowing of ureter or extrinsic compression of ureter from a crossing blood vessel
  • Imaging: extremely dilated renal collecting system without seeing a dilated ureter
  • Clinical: hydronephrosis is most common cause of a renal mass in a neonate and ureteropelvic junction obstruction is the most common cause of hydronephrosis, can present as flank pain in teen after large fluid challenge or as large renal injury after minor blunt abdominal trauma

Radiology Cases of Ureteropelvic Junction Obstruction

IVP of ureteropelvic junction obstruction
4 hour delayed image from an IVP exam shows an extremely dilated left renal collecting system. The left ureter is not seen.
US of ureteropelvic junction obstruction
Sagittal US of the right kidney (upper left) and left kidney (upper right) shows bilateral mild to moderate hydronephrosis. AP image from the excretory phase of an intravenous pyelogram shows bilateral moderately dilated renal collecting systems with normal appearing bilateral ureters.
Sagittal US of the left and right kidneys shows echogenic medullary pyramids bilaterally and mild right hydronephrosis.

Surgery Cases of Ureteropelvic Junction Obstruction

Surgery Cases of Ureteropelvic Junction Obstruction Due to Retrocaval Ureter

Surgery image of retrocaval ureter causing ureteropelvic junction obstruction
Surgical image (above) shows the decompressed distal right ureter (with the black loop around it) emerging from behind the inferior vena cava in the center of the image. The dilated proximal right ureter can be see just to the right of the inferior vena cava at the top of the image. Post operative surgical image (below) shows the red vessel loops around the now decompressed proximal right ureter which has been transected and reanastomosed anterior to the inferior vena cava in the center of the image.

Gross Pathology Cases of Ureteropelvic Junction Obstruction

Gross Pathology Cases of Ureteropelvic Junction Obstruction Due to Pheochromocytoma

Gross pathology image of pheochromocytoma causing ureteropelvic junction obstruction
Sectioned gross pathological image shows an ovoid gray to tan mass surrounded by a thin fibrous capsule that is compressing the right ureter resulting in right hydroureteronephrosis.