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

Abstract

Duplicated collecting systems have a predictable draining pattern that is described by the Meyer-Weigert rule. When there are abnormalities associated with duplicating collecting systems, the upper pole moiety drains inferomedially (most commonly associated with obstruction), and the lower pole moiety drains superolaterally (most commonly associated with vesicoureteral reflux). We present a case of an infant with a duplicated collecting system that violates the Meyer-Weigert rule with lower pole megaureter with massive dilation, ectopic insertion, and associated involuted lower pole renal moiety. To our knowledge, this is the only reported case of a lower pole ectopic ureter with an involuted lower pole renal moiety.

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

“…6 ). Although in most cases, the location of two separate ureteral orifices followed the Meyer Weigert rule, exceptions have been reported [6] , [7] , [8] . The American Urologic Association (AUA) guidelines for urolithiasis recommend obtaining additional imaging for complex anatomy [9] .…”

Multi Imaging Modality in Diagnosis of Unusual Giant Hydronephrosis of the Non Functioning Lower Moiety in A Partial Duplex Kidney with Distal Ureteric Stricture

“…Incomplete duplex kidney, the upper moiety hydronephrosis is usually due to the obstruction at the lower end (ureterocele) while in the lower moiety it is usually due to the vesico-ureteric reflux obeying the Meyer Weigert law [19,20]. However, a few exceptions to the Meyer-Weigert rule has also been published that deal with anatomical variation or ectopic insertion of the ureter of the lower renal pole with vesico-ureteric reflux [21,22] and lower distal ureteric stenosis [23,24].…”