Diagnosis of unilateral single system ectopic ureter in girls in the era of magnetic resonance urography (MRU)

ABSTRACT

Objective: The ectopic ureter frequently drains an ectopic dysplastic or hypoplastic kidney. The present study aims at defining the role of MRU in establishing the diagnosis of this anomaly. Patients and Methods: Between February 1996 and March 2000; 11 girls presented or were referred to our department for management of urinary incontinence. Their age at presentation ranged from 4-9 years (mean 6.5 years). Radiological work up included abdominal ultrasound (US); excretory urogram (IVU); voiding cystourethrography (VCUG); 99 m technetium-dimercaptosuccinic acid (99m Tc-DMSA) renal scan; enhanced spiral computed tomography (CT) and magnetic resonance urography (MRU). Results: Ultrasound showed evidence of a solitary kidney with failure to visualize a contralateral kidney in 7/11 patients. In the remaining 4 patients (36.4); US revealed a pelvic kidney in two and a pelvic cystic mass in another two patients. IVU revealed only one functioning renal unit in all cases. None of the patients showed vesicoureteral reflux on VCUG. On 99m Tc-DMSA ; a single kidney was seen in 9/11 patients and ectopic pelvic kidneys with normal contralateral kidneys in 2/11 patients. The 7 patients; in whom US and 99m Tc-DMSA scan had failed to localize the kidney; underwent CT scanning which visualized a pelvic hypoplastic kidney with a normal contralateral kidney in 2/7 patients. The remaining 5 patients underwent MRU that disclosed a normal kidney with a contralateral lumbar hypoplastic kidney in one and a pelvic ectopic kidney in four. The patients were managed by nephrectomy (n=9) and ureteroneocystostomy (n=2). Conclusions: A single system ectopic ureter should be suspected in all girls with continuous urinary dribbling after the age of successful toilet training. With the inclusion of MRU into radiological workup; dysplastic or hypoplastic kidneys can be accurately localized. MRU is indicated for the diagnosis and for therapeutic planning in such cases