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 Table of Contents  
Year : 2021  |  Volume : 7  |  Issue : 2  |  Page : 145-147

Unilateral complete duplex ureter – report of a rare underdiagnosed anomaly

Department of Anatomy, Pondicherry Institute of Medical Sciences, Puducherry, India

Date of Submission07-May-2021
Date of Acceptance12-Jul-2021
Date of Web Publication30-Dec-2021

Correspondence Address:
C Naga Jyothi
Department of Anatomy, Pondicherry Institute of Medical Sciences, Puducherry
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/jcrsm.jcrsm_34_21

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Duplex ureters are congenital malformations with varying clinical consequences. Identification of this entity is pivotal as exemplified by the failure of first-line investigations to explain the cause for some presenting symptoms in few cases. We report an interesting case of complete duplication of the right ureter in a male cadaver. A brief review regarding embryogenesis, association with other anomalies, and clinical significance is discussed.

Keywords: Complete double ureter, congenital renal anomalies, developmental abnormalities of the excretory system, double ureter

How to cite this article:
Jyothi C N, Sriambika K. Unilateral complete duplex ureter – report of a rare underdiagnosed anomaly. J Curr Res Sci Med 2021;7:145-7

How to cite this URL:
Jyothi C N, Sriambika K. Unilateral complete duplex ureter – report of a rare underdiagnosed anomaly. J Curr Res Sci Med [serial online] 2021 [cited 2022 Jun 28];7:145-7. Available from: https://www.jcrsmed.org/text.asp?2021/7/2/145/334456

  Introduction Top

Numerous congenital anomalies involving the kidney, ureter, and bladder have been described with a duplex collecting system, essentially the duplex ureter, in particular, being the most common anomaly with a reported incidence of 0.8%.[1] Some of these anomalies are associated with a wide variety of other congenital genitourinary tract abnormalities and have been explained significantly from an embryological point of view. They manifest clinically with complications ranging from subtle infections to potentially threatening conditions requiring active surgical intervention.[2] Hence, a thorough and sound knowledge of the embryological anatomy of the urinary system mandates various urogenital and gynecological surgeries for detection as well as averting complications stemming from these complex surgeries.[3]

  Case Report Top

During routine dissection of cadavers as part of the accomplishment of undergraduate medical teaching in our institute, we encountered a male cadaver aged roughly around 45 years. After completion of dissection of the abdominal wall with underlying muscles and various peritoneal reflections, further dissection of vital viscera such as stomach, duodenum with the pancreas, small and large bowel, liver, gallbladder, and spleen was performed methodically, and finally, both kidneys with ureters and urinary bladder were exposed. Complete duplication of the right ureter was observed with one of the ureters arising from the upper pole of the corresponding kidney and the other originating from the lower pole [Figure 1]. This was further confirmed on cross-sectioning the kidney where independent draining units were noted [Figure 2]. Both the ureters were seen draining separately into the urinary bladder. When the interior of the urinary bladder was exposed, two orifices were noted. Formalin was injected separately into the ureters through a 20-cc syringe to identify the mode of drainage, and it was found that the orifice of the ureter draining the upper pole was situated inferior and medial to the orifice of the ureter draining the lower pole [Figure 3]. No other significant anomalies were detected.
Figure 1: Complete double ureter on the right side

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Figure 2: Coronal section of the right kidney showing origin of renal pelvis from the upper lobe of the kidney and another from the lower pole of the kidney

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Figure 3: Interior of urinary bladder with double ureteric opening on the right side: Red arrow showing the ureteric opening draining from the upper pole of the right kidney, yellow arrow showing additional ureteric opening draining from the lower pole of the right kidney (as per Weigert–Meyer rule)

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  Discussion Top

Congenital anomalies of the abdominal viscera are quite common, and anomalies of the urinary tract are frequent and account for more than 50% of cases. Malformations of the urinary system account for 3% of live births.[3] Duplex systems are common with ureters being most commonly afflicted with a reported incidence of 0.8% as described by Privett et al.[1] Mega ureter and duplications are the ones that have been well documented and described for ages. A strong embryological basis lies at the backdrop of all these anomalies.[2]

Normal ureters are a pair of muscular tubes extending from the renal pelvis to the posterior surface of the urinary bladder, with each one of them measuring approximately 25–30 cm in length and 3 mm in diameter.[2] Embryologically, the genitourinary system begins with the formation of pronephros and mesonephros. A series of complex epithelial–mesenchymal interactions lead to the development of the Wolffian duct which elongates caudally and fuses with the cloaca. Under the influence of signals from metanephric mesenchyme, the distal portion of the Wolffian duct differentiates into the ureteric bud. This is mediated by the expression of glial cell line-derived neurotrophic factor ligands of metanephric mesenchyme interacting with Ret/GFRa1 receptor complex situated on Wolffian duct epithelium through a restricted signaling pathway. Unrestricted signaling results in the formation of multiple ureteric buds culminating in multiplex collecting systems. Further successive division of the ureteric bud results in the genesis of the ureter, renal pelvis, and major and minor calyces.[4]

Early splitting of ureteric buds results in duplication of ureters, and this may be complete or incomplete.[3] Incomplete duplication is thrice more common than complete with a frequency of 1 in 500 and is otherwise termed bifid ureter. For reasons unexplained, it is more common in females, particularly on the right side. Another plausible explanation for a bifid ureter lies behind the fact that division of ureteric bud occurs before penetration of the metanephric tissue.[5] Unilaterality is a common finding; however, bilaterality is encountered in 0.2% or 1 in 800 cases.[6] Autopsy studies report occurrence of unilateral ureteral duplication in 0.8% and bilateral duplication in 0.16%–0.32%.[7] No specific explanations or studies have been attributed to unilaterality.

Incomplete duplications are asymptomatic and less significant from a clinical point of view mostly going unnoticed, only to be detected at autopsy.[2] On the other hand, complete duplications are usually associated with other congenital anomalies and manifest clinically with varying presentations, such as vesicoureteric reflux, nephrolithiasis, urinary tract infections, and obstructive pathology with resultant hydronephrosis and ureterocele.[8] The first case report of a patient with unilateral complete ureteral duplication associated with distal ureteral stone was described by Karakose et al. The patient had abdominal or flank pain and urinalysis showed microscopic hematuria.[9]

In our case, though duplication was seen on the right side, it was a perfect complete one involving a male cadaver. However, the location of the ureteral orifices followed the routine Weigert-Meyer rule, wherein the orifice of the ureter draining the upper pole of the kidney opened inferiorly and medial to the one draining the lower pole.

Duplex ureters have been reported earlier by many authors. The largest known series was published by Lowsly and Kirwori. They reported 18 cases of duplex ureters.[10] Asakawa et al. in 1989 reported five cases of complete duplex ureters.[11] Prakash et al.[8]and Choudhary et al.[12] reported two cases each. Single case reports were also published by Deka and Saikia,[2] Roy et al.,[3] Vaidya et al.,[5] Yonli et al.,[13] Shakthi Kumaran and Chitra,[14] Tang et al.,[15] and Morro et al.[16]

The Association of Duplex Ureters with other congenital anomalies is well recognized. Cases have been reported in association with Goltz syndrome, high cephalad kidney, and external ear anomalies.[7] A genetic basis for ureteral duplication with autosomal dominant trait and incomplete mode of penetrance has even been proposed by Hascalik et al.[17]

To conclude, detection of duplex ureters by prenatal ultrasound is quintessential to avert complications during surgery. Knowledge of anatomical variations of the urinary system is required for many radiologic interventions and urogynecological surgeries.

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Conflicts of interest

There are no conflicts of interest.

  References Top

Privett JT, Jeans WD, Roylance J. The incidence and importance of renal duplication. Clin Radiol 1976;27:521-30.  Back to cited text no. 1
Deka B, Saikia R. A study of human cadaveric ureter by simple dissection method. Int J Anat Res 2016;4:3005-8.  Back to cited text no. 2
Roy M, Singh BR, Gajbe UL, Thute P. Anatomical variations of ureter in central India: A cadaveric study. J Datta Meghe Inst Med Sci Univ 2017;12:277-9.  Back to cited text no. 3
  [Full text]  
Uetani N, Bouchard M. Plumbing in the embryo: Developmental defects of the urinary tracts. Clin Genet 2009;75:307-17.  Back to cited text no. 4
Vaidya YP, Waghmare JE, Tarnekar AM, Shende MR. Unilateral isolated incompletely duplicated ureter. J Mahatma Gandhi Inst Med Sci 2014;19:148-50.  Back to cited text no. 5
  [Full text]  
Davda S, Vohra A. Adult duplex kidneys: An important differential diagnosis in patients with abdominal cysts. JRSM Short Rep 2013;4:13.  Back to cited text no. 6
Varlatzidou A, Zarokosta M, Nikou E, Theodoropoulos P, Kakaviatos D, Piperos T, et al. Complete unilateral ureteral duplication encountered during intersphincteric resection for low rectal cancer. J Surg Case Rep 2018;10:266.  Back to cited text no. 7
Prakash, Rajini T, Venkatiah J, Bhardwaj AK, Singh DK, Singh G. Double ureter and duplex system: a cadaver and radiological study. Urol J. 2011;8:145-8. PMID: 21656475.  Back to cited text no. 8
Karakose A, Aydogdu O, Atesci YZ. Unilateral complete ureteral duplication with distal ureteral stone: A rare entity. Can Urol Assoc J 2013;7:E511-2.  Back to cited text no. 9
Lowsly OS, Kirwori TJ. Clinical Urology. A cadaveric study on accessory renal arteries and its clinical implications. Surg Radiol Anat 2011;33:941-4.  Back to cited text no. 10
Asakawa M, Kubodera T, Okamura Y, Habara K, Ito H. Five cases of the double renal pelvis and ureter. Kaibogaku Zasshi 1989;64:206-9.  Back to cited text no. 11
Choudhary U, Kumar S, Jee K, Singh A, Bharti P. A cadaveric study on anatomical variations of kidney and ureter in India. Int J Res Med Sci 2017;5:2358-61.  Back to cited text no. 12
Yonli DS, Chakroun M, Zaghbib S, Ye D, Bouzouita A, Derouiche A, et al. Bilateral duplex collecting system with bilateral vesicoureteral reflux: A case report. J Med Case Rep 2019;13:128.  Back to cited text no. 13
Shakthi Kumaran R, Chitra R. Unilateral duplex collecting system with incomplete duplication of ureters in right kidney in a male cadaver of Asian origin – A case report. Urol Case Rep 2019;23:99-100.  Back to cited text no. 14
Tang MJ, Arachchi A, Mehdipour R, et al. Unilateral duplex ureter. Int J Anat Var. 2018;11:51-2.  Back to cited text no. 15
Morro RM, Lufukuja GJ, Fabian FM. Bilateral double ureters and accessory renal vessels in a Tanzanian male cadaver: A rare urinary system variation. Int J Anat Var 2011;4:164-6.  Back to cited text no. 16
Hascalik S, Celik O, Yilmaz M, Kirimlioglu H. Coexistent uterine myoma, colon adenocarcinoma ureteral duplication in a young female patient. Inonu Universitesi Tip Fakultesi Dergisi 2004;11:181-3.  Back to cited text no. 17


  [Figure 1], [Figure 2], [Figure 3]


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