Ureteric calculi in a horseshoe kidney

Case contributed by Dr Craig Hacking


Right flank pain.

Patient Data

Age: 60 years
Gender: Male

Horseshoe kidney anatomy with a parenchymal isthmus. Within the right ureter, immediately anterior to it crossing the isthmus, are two 3 mm ureteric calculi lying immediately adjacent to one another. This is causing with periureteric fat stranding that extends for a short segment distal to the point of obstruction. There is upstream dilatation of the right renal pelvis, mild hydronephrosis and some right perinephric fat stranding. No left ureteric calculus or hydronephrosis.

Previously demonstrated 8mm calculus within the right pelvicalyceal system is no longer visible. There is now a 4 mm stone in the same region. Three calculi within left pelvicalyceal system, the largest of which measuring 10 mm, are stable. Renal cysts within the upper pole of the left kidney are stable.

The appendix is normal. Scattered pancreatic calcifications and small bilateral fat containing inguinal region hernias. No free intraperitoneal gas or fluid. The remainder of the imaged intra-abdominal structures are unremarkable on non-contrast imaging. No suspicious bony lesion.


Two small calculi within the proximal right ureter where the the ureter crosses anterior to the isthmus of the horseshoe kidney results in mild upstream hydronephrosis.

Case Discussion

Horseshoe kidney can cause stasis which explains the increased risk of renal calculi formation.

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Case information

rID: 35769
Case created: 22nd Apr 2015
Last edited: 27th Sep 2017
System: Urogenital
Inclusion in quiz mode: Included

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