A 38-year-old woman visited my hospital with recurrent acute pyelonephritis. She underwent all kinds of work-up in the regional hospital. And she has nothing but a diverticular stone in the upper portion in the left kidney.

After some discussions, we decided to try flexible ureteroscopic approach to remove this stone.

<point 1> Is this stone the cause of the recurrent UTI? or the result of the UTI?

<point 2> There seems to be no diverticular neck between the upper minor calyx and the stone. Can we find the stone?

<point 3> The renal parenchyma seems to be thin. After stone removal, there would be no problem? Any possibility of renal parenchymal puncture?

The flexible URS is approaching to the diverticular stone.

I found a small trace of the diverticular neck. Actually, I was not sure this was the very opening of the diverticular neck.

I incised the mucosa and finally found the stone. Fortunately, there was no renal parenchymal puncture because there is a thin layer behind the stone.

<point 4> What is the plan during the follow-up period?