Uncrossed complete ureteral duplication with dysplastic lower moiety: A violation of the Weigert–Meyer law

Renal duplication with ureter duplex not following Meyer-Weigert-Rule with development of a megaureter of the lower ureteral segment due to distal stenosis – A case report

“…As part of the embryologic development, the ureters and their orifices complete a 180-degree clockwise rotation in their longitudinal axis. The proximal bud, which was higher and draining the upper system, is now below the first bud – this way the two ureters cross each other (Meyer-Weigert-Rule) 3 . This paper aims to present an unreported case, in which the lower renal duplication was not associated with a vesicoureteral reflux as the Meyer-Weigert rule requires.…”

Weigert-Meyer Law Violation with Lower Pole Obstruction and Ectopia

“…Lower pole ureter with associated ureterocele and another case with lower pole ureteral ectopia to a vas deferens and epididymis have been previously described, though there was no evidence of associated hydronephrosis of the lower pole in either case [6][7][8]. Distal obstruction secondary to what appears to be an adynamic segment of the lower pole ureter with an ectopic course closer to the bladder neck is exceedingly rare, and no case series reviewed demonstrated this sequela of a duplicated system [1][2][3][4][5][6][7][8][9]. Interestingly, this ureter inserts laterally at the bladder neck, so not only are the ureters uncrossed, but the ectopia is unusually lateral.…”

“…In complete duplication, the ureters typically follow the Weigert-Meyer general rule of the ureters crossing with the upper pole ureter ending up more caudal and medial and the lower pole ureter inserting more craniolateral in the bladder. A case of uncrossed double ureters with lower pole dysplasia have been reported in a symptomatic older child [5]. Ureterocele and ectopia to a vas deferens and epididymis have been previously described, though there was no evidence of hydronephrosis of the lower pole in either case [6][7][8].…”

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

“…Jain et al reported a similar case of a 10-year-old boy with a duplicated collecting system with dysplastic lower pole moiety and ectopic ureter [4]. Darr et al described a similar case of a duplicated collecting system with lower pole megaureter without inferolateral insertion of the lower pole ureter into the bladder, and with associated dysplastic lower pole renal moiety [5].…”