What Happens in the Formation of Ureteral Duplication? A Case Report and Brief Literature Review

Radiologists frequently diagnose two ureteral duplications including complete and incomplete types. Incomplete ureter duplication, which is also called bifid ureter, refers to a situation in which the ureteric bud bifurcates before meeting the metanephric blastema. On the other hand, complete ureter duplication, which is also named double ureter, defines another situation in which two separate ureteric buds, on either side of the embryonic body, are formed from the mesonephric duct (Wolffian duct) and then arrive in the metanephric blastema. Therefore, two separate ureters, renal pelvis, as well as a duplex kidney (upper and lower poles) are formed in a common renal capsula. Embryologically, in complete ureter duplication, the ureteric buds rotate 108 degrees when incorporating into the urogenital sinus, which is known as Weigert-Meyer rule. In this posture, the upper and lower poles of the kidney are drained by the laterocranial and mediocaudal orifice, respectively. Complete duplication is more common in women than men and is often associated with vesicoureteral reflux, ectopic ureterocele, and/or ectopic ureteral insertion. In the present case report, a 40-year-old woman, mainly complaining of abdominal and lower back pain, was discovered to have bilateral complete ureteral duplication on computed tomography (CT) scan, as well as kidney, ureter, and bladder x-ray radiography. Moreover, the embryological causes were discussed in forming the duplicated ureter and duplex collecting system.