[A case of ureteropelvic junction stenosis accompanied by a valve-like structure in the renal pelvis].

A 9-year-old girl visited our clinic with recurrent high fever as her chief complaint. Her excretory urogram showed only a few dilated upper calyces. Retrograde pyelography revealed ureteropelvic junction stenosis with hydronephrosis, so that the ureteral catheter could not be passed through the ureteropelvic junction. A fold-like filling defect was also seen above the ureteropelvic junction. At operation the ureteropelvic junction was found to be markedly obstructed, and a semilunar valve-like structure was also observed above it. The valve-like structure was seen where the fold-like filling defect appeared on the retrograde pyelogram. En bloc resection of the lower part of the renal pelvis with the valve-like structure and the ureteropelvic junction was performed, followed by dismembered uretero-pyeloplasty. Histologically, the valve-like structure was a transverse mucosal fold with a muscle layer and without adventitia. Many cases of ureteral valves have been reported, but none with valves or valve-like structures within the renal pelvis as in our case.