Complete ureteral duplication complicated by multifocal transitional cell carcinoma

Clinical History

An 81-year-old male patient with benign prostatic hypertrophy was referred to our hospital because of insidious onset of progressive fatigue and malaise, associated with terminal haematuria. Laboratory data revealed severe microcytic anaemia (blood count: 2.5g/dL; mean globular volume: 58.2pg) and mild renal insufficiency (creatinine: 1.4mg/dL).

Imaging Findings

A renal and pelvic ultrasound was performed revealing left renal duplication, with major hydronephrosis of the upper moiety and dilatation of ipsilateral ureter. This upper pole also showed low/ absent parenchymal index, suggesting long term obstruction. Some ureteral segments showed wall thickening/ intraluminal masses, and a large mass was seen occupying the bladder lumen, which seemed to invade the left ureterovesical junction.
CT urography (non-enhanced, parenchymal and excretory phases) revealed a left complete ureteral duplication, with major dilatation of the upper moiety. Several intra-luminal soft-tissue density lesions were seen occupying the ureteral lumen along its course. A large heterogeneous mass was also seen in the bladder lumen, invading ipsilateral ureterovesical junction. Lower pole of this kidney showed no pelvic dilatation and a normal parenchymal index. Histological analysis of the bladder wall revealed a high-grade papillary urothelial cancer.

Discussion

Duplication of the renal collecting system may be partial or complete. The former is the most common congenital anomaly in the urinary tract, with an estimated incidence of 1 in 150 cases in autopsy studies. The incidence of complete duplication is approximately 1 in 500 cases, with 20% of these occurring bilaterally [1, 2]. Most of collecting system duplications are associated with a normal renal function, being asymptomatic and an incidental finding on imaging studies [1].

In incomplete duplication, the ureters unite at a variable distance from the kidney, with only one ureteral orifice in the bladder. It may be associated with uretero-ureteral reflux (also known as yo-yo, saddle or seesaw reflux), predisposing the patient to recurrent urinary tract infections. Radiographically, it can be demonstrated by excretory urography, but should be suspected when asymmetric dilatation of one ureteral segment is found [2].

In complete duplication, the ureter of the lower pole generally has a normally positioned ureteral orifice in the bladder. An abnormal insertion may be associated with vesicoureteral reflux (the most common abnormality associated with complete duplication), which should be suspected when hydronephrosis of the lower pole is found in pre or postnatal ultrasound [1]. According to the Weigert-Meyer rule, the ureteral orifice of the upper moiety inserts medially and inferiorly to the orifice of the ureter draining the lower pole [5]; it can also be associated with an ectopic ureterocele, which may be associated with significant renal dysplasia and poor function of the affected segment [1, 2]. Retrograde cystourethrography can show a filling defect in the bladder when ureterocele is present [1, 2]. Ultrasound may show the dilated upper moiety, and/or demonstrate a thin lobulated septation in the bladder representing the ureterocele itself. CT and MRI can demonstrate the hydronephrotic upper moiety and the dilated ureter, as well as its ectopic insertion and the ureterocele in the bladder [1, 2].

Ureteral duplication may also be associated with other renal abnormalities, including cystic renal disease, horseshoe kidney or segmental multicystic dysplasia [2]. There is no known association of ureteral duplication and urinary tract carcinomas, with only anecdotal cases found in the literature. However, some authors postulate the hypothesis that urine reflux chronically irritates the distal segment of a duplicated ureter, rendering this segment susceptible to malignant changes [3, 4]. Therefore, care must be taken in these patients, and urinary tract neoplasms should not be forgotten.

Differential Diagnosis List

Final Diagnosis

Complete ureteral duplication complicated by multifocal transitional cell carcinoma

URL:	https://eurorad.org/case/11311
DOI:	10.1594/EURORAD/CASE.11311
ISSN:	1563-4086