A Case of Ectopic Dysplastic Kidney and Ectopic Ureter Diagnosed by MRI

David T. Duong; Linda M.D. Shortliffe

Disclosures

Nat Clin Pract Urol. 2008;5(11):632-636. 

In This Article

Summary and the Case

Summary

Background: A 14-year-old girl with a solitary right kidney had continuous urinary incontinence. Four months previously she had undergone surgical resection of a vaginal septum associated with uterus didelphys, which was causing obstructed menstrual flow. She was toilet trained at the age of 2 years, had a normal voiding pattern, and had no history or family history of incontinence.
Investigations: Pelvic examination, abdominal and pelvic ultrasonography, renal scintigraphy, voiding cystourethrography, abdominal and pelvic MRI, fluoroscopic retrograde vaginography, vaginoscopy, cystourethroscopy after administration of indigo carmine, laparoscopy, and pathologic examination of the excised specimen.
Diagnosis: Ectopic ureter draining into the vagina associated with a contralateral dysplastic kidney.
Management: Laparoscopic nephrectomy of the left renal remnant and ligation of the left distal ureter.

The Case

A 14-year-old girl with a solitary right kidney, discovered on imaging studies 4 years previously, was referred to a urology department for daytime urinary leakage, which required the use of pads. The urinary leakage began after vaginal surgery, which was performed at another institution 4 months before the referral. She had undergone transvaginal resection of a vaginal septum associated with uterus didelphys that was blocking menstrual flow. Postoperatively, she had regular menses, but marked, persistent urinary leakage. The incontinence seemed to be unpredictable, slow, continuous, and unrelated to physically stressful activities. She denied any pre-existing urinary tract symptoms, previous urologic diseases or urologic surgery. She was toilet trained at 2 years of age and had a normal voiding pattern without incontinence. The patient had no other medical history and took no regular medications. She also had no family history of genitourinary abnormalities.

Physical examination revealed no general physical abnormalities, except for a prepubertal vaginal opening filled with clear fluid. No drainage was visible from her urethra when she coughed or with other stress. Abdominal and pelvic ultrasonography revealed a solitary right kidney with an empty left renal fossa. The right renal parenchyma had normal echogenicity and no signs of hydroureteronephrosis. Planar dimercaptosuccinic acid (DMSA) renal scintigraphy showed only right renal activity, without evidence of other ectopic activity (Figure 1). Voiding cystourethrography (VCUG) demonstrated no vesicoureteral reflux during either filling or voiding phases.

Figure 1.

Renal scintigraphy: 99mTc-dimercaptosuccinic acid planar renogram, 2. 1 mCi. The image demonstrates uptake in the right kidney, but does not demonstrate uptake in the ectopic atretic left renal tissue in the patient's lower abdomen.

Although DMSA renal scintigraphy did not show activity from any ectopic left renal tissue, and VCUG did not show vesicoureteral reflux, an ectopic urinary system was suspected because of the patient's presentation with continuous urinary incontinence. MRI with three-dimensional reconstruction was performed, and revealed a fluid-filled (high T2) tubular structure, arising from another structure (possibly the rudimentary left renal pelvis) at the level of the first sacral vertebra (S1). This structure appeared to insert into the vagina, and likely represented an atretic, ectopic left ureter (Figure 2A). The right kidney had a dilated inferior pole and a single right ureter that inserted normally into the bladder. In addition, two discrete uterine horns with two cervices were visible, as would be expected for a patient with uterus didelphys. The left uterine horn exhibited a high T2 signal, which was consistent with urine from an ectopic insertion of an atretic left ureter (Figure 2B). Following MRI, fluoroscopic retrograde vaginography was performed, which demonstrated a bifid vagina with a smaller right than left vaginal segment, with a partial intervening septum, which was consistent with uterus didelphys and prior vaginoplasty. No reflux from the vagina into a ureter was observed.

Figure 2.

MRI of the patient's abdomen and pelvis. (A) Coronal T2 single-shot fast spin-echo (SSFSE) MRI. The image shows a fluid-filled tubular structure arising from rudimentary left renal pelvis (arrow) at the level of S1, coursing laterally to the left uterine horn, and inserting into the vagina, representing an ectopic left ureter (arrowheads). (B) Axial T2 SSFSE MRI. The image shows the ectopic left ureter (arrowhead) coursing laterally to the left uterine horn (arrow) before inserting into the vagina.

Vaginoscopy confirmed the presence of two cervices, as well as an indentation along the left vaginal wall that could not be catheterized. After intravenous administration of indigo carmine, cystourethroscopy showed clear blue efflux from the normal right ureteral orifice, but no colored drainage from the left ureteral orifice, nor any vaginal drainage. No left-sided ureteral orifice was found along the trigone, bladder neck, or urethra. The bladder was otherwise normal.

Laparoscopy revealed a bicornuate uterus. No kidney was identified in the left renal fossa, and the small renal remnant could not be located on initial examination; however, with further exploration using the MRI-visualized position relative to the S1 vertebral body, and after some dissection, a fibrovascular structure was found adjacent to the left ovary, which was consistent with a remnant atrophic, ectopic kidney. Emerging from this presumed renal remnant was a thickened tubular structure encased in fibrovascular tissue. A gush of blue fluid was seen when the tubular structure was transected, confirming that this structure was the ureter draining the ectopic, dysplastic kidney. A 5 Fr catheter was then passed laparoscopically through the cut ureteral end into the vagina, confirming the ectopic ureteral insertion. The distal left ureter was ligated with an endoscopic TIA stapler.

Pathologic examination of the specimen verified a 3.0 × 1.5 × 1.2 cm atrophic, malformed kidney with areas of tan-red cortex and white, fibrous soft tissue. The girl had no postoperative complications, and was discharged 2 days after surgery. Seven months after the operation, the patient reported no vaginal discharge or urinary incontinence.

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