Presentation
Gross hematuria with lesion not seen on CT urography.
Patient Data
In the right kidney upper pole there are two minor calyces into which multiple papilla empty. These have a more "ballooned" or "T-shape" than a normal minor calyx would.
For comparison, one of the papilla in the upper pole and the papilla in the lower pole empty into their respective minor calyces.
Incidental: Overlying suture material, retrograde catheter, and an overlying patient button.
Multiple papilla emptying into a common/compound calyx (large blue arrow). The compound calyces are more balloon-shaped or T-shaped in these projections, and in the upper compound calyx on the second image, you can also see the filling defects of two papillary tips entering the minor calyx.
A small dark blue arrow in the second image points to the more normal relationship of single papilla --> single minor calyx.
Case Discussion
Normally, as the kidney develops from lobules, each papilla has a corresponding calyx and infundibulum, emptying into the renal pelvis. In a compound calyx normal variant, multiple papillae empty into a single calyx and infundibulum.
They are more common in the upper pole of the kidney.
They are totally incidental.