Unrecognized complete ureteral duplication with the calculus in the nonstented ureter: A case report

INTRODUCTION: Ureteral duplication is often encountered in association with urinary stones and is usually found by radiologists first. However, in some rare cases, imaging diagnosis can be subtle and even unrecognized. CASE PRESENTATION: A 66-year-old male had A 9-mm stone in the left ureter, another 7-mm stone in the right ureter, and multiple small stones (<4 mm) in bilateral kidneys were detected by noncontrast CT (Fig. 1). As his urine culture was positive, bilateral double-J stent were placed for renal drainage. Two weeks later, repeat CT imaging revealed a left ureteral duplication with a stone in the nonstented ureter and at the intersection level of the two separated ureters. DISCUSSION: Duplication of the ureters is a common anomaly and is frequently encountered by radiologists. However, the diagnosis can be difficult due to the subtilty of the disease, and the condition can even unrecognized when one of the two moieties is small and dysplastic. Careful preoperative CT evaluation and intraoperative confirmation are necessary to ensure D-J stents are inserted into the target ureter. And when a ureteral stone is seen at the intersection of two ureters in the CT image, the location of which may be at the intersection of the Y-shaped ureter of the incomplete ureteral duplication or just one of the two separated complete ureteral duplications, hydronephrosis in the upper ureter is helpful to determine the location of the stones. CONCLUSION: Imaging diagnosis of complete ureteral duplication can be easily missed when one of the two moieties has hydronephrosis, which makes the other one relatively small. Our case highlights the importance of a careful preoperative imaging evaluation and detection of complete ureteral duplication with calculus disease.