單側完全型雙套輸尿管合併結石及腎積水:罕見病例報告及文獻回顧

陳冠宇^1,2、陳順郎^1,2、王紹全^1,2、謝佐宜^1,2、陳文榮^1,2、宋文瑋^1,2、何承儒^1,2、楊旻鑫^1,2

¹中山醫學大學附設醫院 泌尿科；²中山醫學大學醫學院

Unilateral complete duplication with ureteral urolithiasis and obstructive uropathy: a rare case report and literature review.

Kuan-Yu Chen^1,2, Sung-Lang Chen^1,2, Shao-Chuan Wang^1,2, Tuzo-Yi Hsieh^1,2, Wen-Jung Chen^1,2, Wen-Wei Sung^1,2, Cheng-Ju Ho^1,2, Ming-Hsin Yang^1,2

¹ Department of Urology, Chung Shan Medical University Hospital, Taichung, Taiwan;

² School of Medicine, Chung Shan Medical University, Taichung, Taiwan

Introduction: Ureter duplication, accounting for 0.8% to 5% of the population^[1], is the most common congenital anomaly of the urinary tract^[2]. Embryologically, duplication occurs when two separate ureteric buds arise from a single Wolffian duct. Partial duplication is more common than complete duplication. In complete duplication, there are separate pelvicaliceal systems and ureters. If ectopic ureter presents, it may cause obstructive uropathy, vesicoureteral reflux, or incontinence. Ureterolithiasis, on the other hand, is one of the most common diseases in urologic clinical practice. We present a case of unilateral complete ureteral duplication with a ureteral stone and hydronephrosis in a young man who presented with right lower abdomen pain and hematuria.

Case presentation: A 22-year-old man without a known underlying disease presented with right lower abdomen pain and hematuria for 1 week. He went to a local clinic for help and was found to have possible hydronephrosis. He was referred to our outpatient department for a second opinion. Physical examination showed right costovertebral angle percussion tenderness. KUB showed a 5mm high-density focus lesion at the right upper abdomen, and sonography confirmed right hydronephrosis. Under the impression of the suspect right upper third ureter stone, the patient had extracorporeal shock wave lithotripsy on 2024-03-01. Follow-up KUB and sonography showed remaining stone and obstructive uropathy. After a discussion with the patient, a right ureteroscopy for lithotripsy was performed on 2024-03-12. Polyps formation and extreme stricture of the right ureterovesical junction were noted during the operation, the ureteroscopy reached the renal pelvis but no visible ureter stone was found. A double J stent was placed in case of the possibility of flushing the stone back to the renal pelvis. Nevertheless, sonography revealed persistent hydronephrosis. Abdomen CT scan on 2024-03-20 showed duplication of the right collecting system, a hyperdense stone at lower pole moiety with hydronephrosis, and retained double J stent at upper moiety. We consulted radiology for antegrade guidewire placement and performed a right ureteroscopy lithotripsy on 2024-03-26. The patient tolerated the operation well and was discharged from our hospital on 2024-03-27.

Discussion: According to the Weigert-Meyer rule, which is typical of a complete duplicating system, the upper renal moiety ureter has ectopic insertion medial and inferior to the lower renal moiety ureter, which frequently ends in a ureterocele. In contrast, the lower renal moiety ureter usually has orthotopic insertion, but vesicoureteral reflux may occur due to lateral displacement ^[3]. Being curious about the incidence and correlated outcomes, we searched PubMed with the Mesh term keywords ("Cakut" [Supplementary Concept]) AND "Urolithiasis"[Mesh], and three publications were found. Only one of the articles discussed the greater prevalence of hypercalciuria and/or hypocitraturia in unilateral renal agenesis (URA) children than in the general population ^[4]. We searched with more general keywords of (ureter stone) AND (complete duplication) in PubMed, and 22 results were found. After reviewing the articles, we found 9 articles that conform to our interests in the past 10 years, and all of them were case reports [Appendix]. No meta-analysis or review article has been published to date.

In this case, we presented a ureter stone hidden in a complete duplex system in a young adult. Without computed tomography or intravenous pyelography, duplicated ureters might slip our minds when handling highly suspected urolithiasis. Considering the interval between the imaging study and the operation, the assumption of stone passage may get the upper hand. When the wrong ureter is stented and leaves the patient with an obstructed system, the risk of infection and exposure to repeat imaging and procedures also rises ^[5].

Conclusion: This case demonstrated the possible unawareness of duplicated ureter in managing urolithiasis. A diagnosis of ureter duplication should be considered in patients with persistent clinical symptoms and imaging studies. Voiding cystourethrogram, contrast computed tomography, or intravenous pyelography is useful when suspicious of a duplex collecting system. Further analysis would help establish the incidence data and correlated outcomes of ureter duplication with urolithiasis.