The duplicated collecting system of the urinary tract: embryology, imaging appearances and clinical considerations

Abstract

Duplication anomalies of the urinary collecting system are common and can be discovered and characterized with multiple imaging modalities. The embryology, imaging manifestations and clinical ramifications of duplicated ureters and renal collecting systems vary from a normal anatomical variant to urological pathology and are discussed and illustrated in this review.

Massively Dilated Lower Pole Ectopic Megaureter with Involuted Lower Pole Renal Moiety and Collecting System: An Exception to the Meyer-Weigert Rule

“…Most cases of renal duplication are not associated with other abnormalities. However, when abnormalities are present, the upper pole ureter is typically associated with obstruction from ectopic insertion, and the lower pole ureter is typically associated with vesicoureteral reflux [3]. We report a rare case of an exception to the Meyer-Weigert rule in which there is lower pole obstruction secondary to ectopic insertion with involution of the lower pole renal moiety.…”

Prenatal imaging features and postnatal outcomes of isolated fetal duplex renal collecting system: A systematic review and meta‐analysis

“…Duplex collecting system (DCS) is one of the most common urinary tract anomalies reported in the pediatric literature, with an incidence ranging from 0.7% to 4% . DCS is characterized by the presence of two pyelocaliceal systems within the same renal unit due to an incomplete fusion of upper and lower pole moieties, resulting in a variety of complete or incomplete duplications of the collecting system with single or double ureters …”

“…Duplex collecting system (DCS) is one of the most common urinary tract anomalies reported in the pediatric literature, with an incidence ranging from 0.7% to 4%. 1 DCS is characterized by the presence of two pyelocaliceal systems within the same renal unit due to an incomplete fusion of upper and lower pole moieties, resulting in a variety of complete or incomplete duplications of the collecting system with single or double ureters. 1 Prenatal diagnosis of DCS relies on the visualization of two noncommunicating renal pelvises, pelvis dilatation or cystic areas in the upper or lower pole representing calyceal or ureteral dilatation and the presence of a cystic anechoic structure within the bladder suggesting a ureterocele 2 (Figure 1).…”

“…1 DCS is characterized by the presence of two pyelocaliceal systems within the same renal unit due to an incomplete fusion of upper and lower pole moieties, resulting in a variety of complete or incomplete duplications of the collecting system with single or double ureters. 1 Prenatal diagnosis of DCS relies on the visualization of two noncommunicating renal pelvises, pelvis dilatation or cystic areas in the upper or lower pole representing calyceal or ureteral dilatation and the presence of a cystic anechoic structure within the bladder suggesting a ureterocele 2 (Figure 1). The actual detection rate of ultrasound in detecting DCS has not been consistently reported, and the large majority of cases diagnosed before birth are those presenting with dilatation of one or both renal moieties, while those cases not presenting with dilatation may be easily overlooked at the scan.…”

Acute pyelonephritis revealing an intraprostatic obstructive megaureter in an adult: A rare finding

“…Duplicated renal collecting system is one of the most common congenital upper urinary tract abnormalities [ 1 ]. Estimated prevalence ranges between 0.3–6% in the general population [ 2 , 3 ]. Although considered an anatomical variant, duplex collecting system may be complicated by vesicoureteral reflux, ureterocele, or ectopic ureter [ 4 ].…”