[A case of valve-like structure in ureter associated with pyonephrosis due to Salmonella infection].

A 7-year-old boy had a fever of 39 degrees C. Abdominal computed tomography (CT) revealed marked left hydronephrosis with hydroureter. Percutaneous nephrostomy was performed. Salmonella infanitis was detected from the drainage urine. Cystourethrography after nephrostomy showed bilateral vesicoureteral reflex (VUR). On the left side, ureteropelvic junction (UPJ) stenosis was found. Left fistelography showed hydronephrosis, but the ureter was not visualized. A mechanism like a valve at the left UPJ was suggested; the bladder urine was able to ascend to the pelvis but not to be drained from the pelvis. The left renal function was not expected to recover from the findings of renal scintigram and CT. Left nephroureterectomy and right anti-VUR operation were performed. The extirpated renal and ureteral specimens revealed a nonpapillary tumorous structure like a valve at the left UPJ. The histological examination of the valve-like structure revealed the presence of two muscle layers without an adventitia folded at the UPJ.