Duplication of collecting system is most common congenital urinary tract anomaly
; Spectrum from bifid renal pelvis to complete duplication (Incomplete : complete = 2:1)
Ectopic ureter
– Ureteral orifice below normal insertion in trigone; commonly associated with duplex collecting system
Duplicated ureter
– 2 ureters drain duplex kidney and remain separate down to bladder insertion or beyond
Upper moiety
– Inferomedial ectopic insertion (Weigert-Meyer rule)
– Ectopic ureterocele
– Obstruct
Lower moiety
– Inserted in trigone (orthotopic)
– Reflux (due to maldevelopment of valve mechanism)
Ectopic ureterocele
– Ectopic insertion of upper moiety ureter with accompanied ureterocele
– Causing obstruction
![Illrustration from Diagnostic imaging, Genitourinary](https://q-radiology.com/wp-content/uploads/2022/12/image-164.png)
![Dilated upper pole of left kidney](https://q-radiology.com/wp-content/uploads/2022/12/image-166.png)
Intravenous Pyelogram (IVP)
– Drooping lily (lower pole compressed by dilated upper moiety)
– Nubbin sign (severe scarring in lower pole due to reflux)
– Yo-yo phenomenon (incomplete duplication with distal obstruction)
![Gaillard F, Duplex collecting system - drooping lily sign. Case study, Radiopaedia.org (Accessed on 12 Dec 2022) https://doi.org/10.53347/rID-12774
Abdominal Radiology volume 41, pages340–341 (2016)](https://q-radiology.com/wp-content/uploads/2022/12/image-165-1024x506.png)
Abdominal Radiology volume 41, pages340–341 (2016)
![Nubbin sign](https://q-radiology.com/wp-content/uploads/2022/12/image-167.png)
![Drooping lily sign](https://q-radiology.com/wp-content/uploads/2022/12/image-168-1024x612.png)