Bladder, ureter & renal pelvis

Congenital anomalies

Ureters-congenital anomalies

Last author update: 1 May 2012
Last staff update: 18 November 2021

Copyright: 2002-2023,, Inc.

PubMed Search: Ureters [title] "congenital abnormalities"

Sean R. Williamson, M.D.
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Table of Contents
Definition / general
Cite this page: Williamson SR. Ureters-congenital anomalies. website. Accessed September 26th, 2023.
Definition / general
  • Diverticula:
    • Congenital diverticulum results from aberrant development of ureteric bud (true diverticulum including all layers of normal ureter wall)
    • Pseudodiverticulum results from mucosal protrusion through a defect in the ureter wall (due to instrumentation, surgery, stone, obstruction, et cetera)
    • Can be asymptomatic or cause recurrent urinary tract infections
    • Lined by urothelium, sometimes squamous metaplasia or ureteritis glandularis
  • Double / bifid ureters:
    • Relatively common incidental finding, associated with duplication of renal pelves
  • Ectopic ureter:
    • More common in women
    • Ureter may terminate into structures such as proximal urethra, seminal vesicle/ejaculatory duct, vas deferens, fallopian tube, uterus or vagina
  • Hydroureter:
    • May have neurogenic cause
  • Megaloureter (megaureter):
    • Often divided into primary obstructed and primary refluxing megaureter
    • May have smooth muscle defect (such as apoptosis of smooth muscle in primary obstructive cases)
    • Defective interstitial cell of Cajal-like cells have been hypothesized to be involved in refluxing cases (Urology 2009;74:318)
  • Ureteral agenesis:
    • Mesonephric diverticulum does not develop
    • Associated with failure of ipsilateral kidney to develop (usually unilateral, bilateral Potter’s syndrome is fatal)
  • Ureteropelvic junction obstruction:
    • One of the most common causes of hydronephrosis in children
    • More common in males and on left side, 20% bilateral
    • May be associated with agenesis of contralateral kidney
    • May be due to abnormal organization of smooth muscle bundles (intrinsic obstruction thought to be associated with less dense muscle and increased collagen, compared to obstruction due to crossing of renal vessel, Urology 2010;76:181)
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