Diagnostic Value of Real-Time Ultrasound in Congenital Segmental Giant Megaureter: A Case Report

: Congenital segmental giant megaureter (CSGM), which refers to segmental cystic dilatation of the upper collecting system, is extremely rare in the pediatric population. Depending on the etiology, the condition could be categorized as primary or secondary megaureter with three subtypes including refluxing, obstructed, nonrefluxing and nonobstructed types. We report a case in which the CSGM presented as a giant abdominal cystic mass with associated right-sided hydronephrosis that was diagnosed by abdominal ultrasound. Cystic mass and the tubular structure at the caudal side of the cystic mass were demonstrated on abdominal ultrasound. We identified a connection between the cystic mass and the lumen of the tubular structure. Therefore, the cystic mass was reported as CSGM on abdominal ultrasound, especially categorized as the nonrefluxing and nonobstructed type. The percutaneous nephrostomy was performed to relieve hydronephrosis, followed by excision of the dilated segment. CSGM is an extremely rare presentation of megaureter, requiring variable imaging modalities and an appropriate intervention. Especially, careful real-time ultrasound was critical to identify the CSGM promptly and essential for the individual appropriate management.