Bilateral duplex kidney and ureter with multiple stones: a case report.

BACKGROUND: Bilateral duplicated kidney and ureter is a rare condition in urology, and it is even rarer for patients to have multiple stones simultaneously. We delineate the diagnostic and therapeutic trajectory of a patient presenting with bilateral duplex kidneys and ureters, characterized by the presence of multiple stones. Notably, the left kidney is a complete duplication, whereas the right kidney exhibits an incomplete duplication. CASE PRESENTATION: A 47-year-old male patient was diagnosed with bilateral duplex kidney and ureter combined with multiple stones. Ureteral flexible lithotripsy and percutaneous nephrolithotomy were performed successively in our hospital. On the postoperative five day, he was discharged from the hospital without apparent discomfort.The double J tube was pulled out one month later, and no stone recurrence was found after 3 months of follow-up. CONCLUSIONS: Bilateral duplicated renal ureteral malformations combined with multiple stones are very rare. Stones can be removed by ureteroscopic lithotripsy or percutaneous nephrolithotripsy and sometimes multiple procedures are required, which should be chosen according to the patient's relevant condition.

Primary retroperitoneal mucinous cystic tumour of borderline malignancy mimicking kidney duplicate: cases report and literature review.

BACKGROUND: Primary retroperitoneal mucinous cystic tumours with borderline malignancy (PRMC-BM) are rare and difficult to diagnose preoperatively. We are the first to report two cases of PRMC-BM which mimic a duplex kidney and evaluate the outcomes of different surgical procedures. CASE PRESENTATION: We describe two cases of retroperitoneal cystic tumours. Both were diagnosed with duplex kidney with hydronephrosis on computed tomography scan. The first patient underwent robot-assisted laparoscopic surgery and was found to have a retroperitoneal cystic tumour. The other patient underwent an ultrasound-guided puncture before surgery and was diagnosed with retroperitoneal lymphangioma. Retroperitoneal cystectomy was performed using an open transperitoneal procedure. The final pathologic diagnosis in both cases implies PRMC-BM. The open surgical approach was associated with a shorter operation time, less intraoperative blood loss, and protected cyst wall integrity by comparing the different surgical approaches. During follow-up, the patient in the first case had tumour recurrence six months post-surgery, and the other patient was healthy without recurrence or metastasis 12 months post-surgery. CONCLUSIONS: Primary retroperitoneal mucinous cystic tumours with borderline malignancy can be enclosed within the kidney and misdiagnosed as other cystic diseases of the urinary system. Thus, an open surgical approach may be more suitable for this type of tumour.

Duplex kidney complicated with preoperative inferior nephroblastoma rupture in children: a case report and literature review.

BACKGROUND: We admitted a child with a duplex kidney combined with preoperative rupture of nephroblastoma and used this case to discuss the clinical features and treatment of this disease. CASE PRESENTATION: We retrospectively analyzed the clinical data of a 5-year-old girl with preoperative duplex kidney rupture combined with inferior nephroblastoma who was admitted to the Fourth Hospital of Baotou. In addition, we reviewed the relevant literature. The patient's details were as follows: weight, 17 kg; height, 108 cm; and body surface area, 0.7 m2. Abdominal ultrasound for abdominal pain revealed the presence of a left-sided renal mass; enhanced abdominal computed tomography further confirmed it to be a left-sided duplex kidney measuring approximately 6 × 5 × 5 cm, with a rupture originating from the lower kidney. The PubMed database was searched from 2010 to 2020 for the terms "Wilms' tumor" and "Duplex" and "Wilms' tumor" and "Rupture." The treatment plan was preoperative chemotherapy (vincristine/dactinomycin, VA regimen) + left kidney tumor radical surgery + postoperative chemotherapy (actinomycin-D/VCR/doxorubicin, AVD regimen). Postoperative pathology revealed an International Society of Pediatric Oncology intermediate-risk stage-3 nephroblastoma (mixed type) in the left kidney. Literature review was performed with 71 cases meeting the set criteria with an aim to analyze and summarize the clinical characteristics and treatment of patients with ruptured nephroblastoma and duplex kidney combined with nephroblastoma. CONCLUSIONS: To our knowledge, no previous studies have reported preoperative duplex kidney combined with nephroblastoma rupture. In patients with this condition, preoperative chemotherapy is recommended when the vital signs are stable and tumor resection can be performed after the tumor has shrunk to prevent secondary spread. If the patient's vital signs are unstable, emergency exploratory surgery is needed. If the nephroblastoma rupture is old and limited, surgery can be performed when the tumor size is small.

Functional magnetic resonance urography in infants: feasibility of a feed-and-sleep technique.

BACKGROUND: Functional magnetic resonance (MR) urography has been well established in the diagnostic workup of congenital anomalies of kidneys and urinary tract, though long acquisition time requires sedation or general anesthesia in infants. OBJECTIVE: To evaluate the success rate of an optimized functional MR urography protocol in infants carried out in natural sleep. MATERIALS AND METHODS: We retrospectively evaluated all functional MR urographies performed under general anesthesia or during natural sleep in infants younger than 1 year between 2010 and 2017 and rated image quality in both cohorts using a 3-point Likert scale. We tested the analyzability of functional sequences using a free available software. We also calculated examination time. Finally, we compared examinations in natural sleep and those with general anesthesia using independent t-test for continuous data and Mann-Whitney U test for categorical data. RESULTS: Functional MR urography could be performed successfully during natural sleep in 38 of 42 (90%) infants younger than 10 months. Four examinations were aborted before contrast medium was administrated. In the same period, 19 functional MR urographies were performed successfully under general anesthesia. Although image quality was significantly better in this group (P<0.0001), image quality was at least diagnostic in all finished examinations in natural sleep, and the functional analyzability was given in all completed examinations. There was a significant saving in examination time during natural sleep (P<0.001). CONCLUSION: Functional MR urography can be successfully performed in natural sleep in infants younger than 10 months.

[Laparoscopic ureteropyeloanastomosis in iatrogenic trauma of the upper pole ureter in a duplex kidney].

In case of stricture of the lower third of ureter in patients with duplex kidney, ureteroneocystostomy or transureteroureterostomy can be used. Anastomosis of the injured ureter of the upper pole with the pelvis of the lower pole is considered nontypical. In this clinical observation, a 46-year-old patient with iatrogenic trauma of the pelvic part of the upper pole of a duplex kidney successfully undergone laparoscopic ureteropyelostomy. There were no complications; the stent was removed after 4 weeks. During the follow-up examination, the function of both kidneys was within normal range and there were no disturbances in the urine passage in the upper urinary tract. Thus, laparoscopic ureteropyelostomy provided an adequate urine passage from the duplex system kidney through the healthy ureter.

[Uretero-ureteral anastomosis (ureteropyeloanasto-mosis) for the duplicated upper urinary tract in children].

INTRODUCTION: The duplex kidney is one of the most common congenital abnormalities of the urinary tract, and various surgical procedures exist for the management of this condition. Depending on the surgeon preferences, patients with duplex kidney may undergo heminephrectomy with ureterectomy using open or laparoscopic approach, uretero-cysto-anastomosis of the ectopic ureter or two ureters in a single block. Recently, there have been reports of inter-ureter anastomoses. Here we report our multicenter experience in open and laparoscopic uretero-ureteral anastomosis (UUA). The study aimed to improve the treatment results in children with urodynamic dysfunction due to the duplicated upper urinary tract. MATERIALS AND METHODS: We retrospectively analyzed medical records of 64 children treated from 2007 to 2017. There were 22 (32.8%) boys and 43 (67.2%) girls with mean age 40.2 months at the time of surgery. All of them had duplex kidneys, including 27 (42.2%) right-sided and 37 (57.8%) left-sided. Of them, 15 (23.4%) children underwent distal UUA (DUAA), and 49 (76.6%) had proximal UUA (PUUA). RESULTS: After surgery, acute pyelonephritis occurred in three patients. In the early postoperative period, a prolonged urinary leakage from surgical site drainage was observed in three (6.1%) patients after laparoscopic PUUA. One (4.2%) child developed a stumpitis. Thus, complications occurred in 7 (10.9%) children; one of them (1.6%) needed additional treatment. CONCLUSION: Distal and proximal UUA is a safe and effective surgical treatment for urinary outflow disorders in patients with the duplicated upper urinary tract, minimizing the risk of the duplex kidney dysfunction.

Renal anomalies and lymphedema distichiasis syndrome. A rare association?

Lymphedema distichiasis syndrome (LDS) is a rare, autosomal dominant genetic condition, characterized by lower limb lymphedema and distichiasis. Other associated features that have been reported include varicose veins, cleft palate, congenital heart defects, and ptosis. We update a previously reported family with a pathogenic variant in FOXC2 (c.412-413insT) where five affected individuals from the youngest generation had congenital renal anomalies detected on prenatal ultrasound scan. These included four fetuses with hydronephrosis and one with bilateral renal agenesis. A further child with LDS had prominence of the left renal pelvis on postnatal renal ultrasound. We also describe a second family in whom the proband and his affected son had congenital renal anomalies; left ectopic kidney, right duplex kidney, and bilateral duplex collecting systems with partial duplex kidney with mild degree of malrotation, respectively. Foxc2 is expressed in the developing kidney and therefore congenital renal anomalies may well be associated, potentially as a low penetrance feature. We propose that all individuals diagnosed with LDS should have a baseline renal ultrasound scan at diagnosis. It would also be important to consider the possibility of renal anomalies during prenatal ultrasound of at risk pregnancies, and that the presence of hydronephrosis may be an indication that the baby is affected with LDS.

Long-term functional renal outcomes after retroperitoneoscopic upper pole heminephrectomy for duplex kidney in children: a multicenter cohort study.

BACKGROUND: Retroperitoneoscopic upper pole heminephrectomy (RUHN) in duplex kidney in children remains a challenging procedure with a need for postoperative functional assessment of the remnant lower pole. We aimed to calculate the incidence of long-term functional renal outcomes in these children and examine the effect of age on those outcomes. METHODS: A multicenter retrospective cohort study of 9 years included all patients undergoing RUHN and evaluated by renal ultrasound (US) and dimercaptosuccinic acid (DMSA) scintigraphy pre and postoperatively. Patients were divided in two age groups of ≤12 and >12 months. Standard follow-up assessed pre-, intra- and postoperative outcomes using clinical review, US and DMSA. RESULTS: Standard RUHN in lateral position was performed in 30 patients. Five cases were excluded (2 lacks of postoperative DMSA, 3 conversions). Indications for RUHN were non-functioning upper moieties (n = 25) caused by ureterocele (n = 11), ectopic distal implantation of the ureter with incontinence (n = 6) or evolving severe ureterohydronephrosis (n = 8). Mean age at surgery was 30 ± 27 months, operation time 116 ± 52 min and hospital stay 2.8 ± 1 days. Long-term follow-up (mean, 7.2 ± 2.7 years) with US and DMSA showed that none of the 25 patients had complete loss of lower pole renal function. Mean lower pole renal function directly related to RUHN was not significantly different after versus before RUHN for the entire cohort (n = 24; 39.7 ± 7.90 % vs. 41.7 ± 6.74 %; p = 0350), for the ≤12-month (n = 6; 39.3 ± 4.18 vs. 41.3 ± 5.47; p = 0.493) and the >12-month groups (n = 18; 39.8 ± 8.90 vs. 41.9 ± 7.25; p = 0.443). Four patients (17 %) had partial loss of function (mean function loss, 9.3 ± 5.85 %; median age, 13 months). The number and type of complications between the two age groups were not statistically different. Overall, 29 % (n = 7/24) of the patients presented with medium-term (17 %) and long-term (17 %) complications directly related to RUHN. CONCLUSIONS: RUHN is a demanding yet efficient technique that is safe for the lower pole at any age. Systematic postoperative DMSA is not mandatory as long as US remains normal.

The duplicated collecting system of the urinary tract: embryology, imaging appearances and clinical considerations.

Duplication anomalies of the urinary collecting system are common and can be discovered and characterized with multiple imaging modalities. The embryology, imaging manifestations and clinical ramifications of duplicated ureters and renal collecting systems vary from a normal anatomical variant to urological pathology and are discussed and illustrated in this review.

A comparison between laparoscopic and retroperitoneoscopic approach for partial nephrectomy in children with duplex kidney: a multicentric survey.

PURPOSE: To compare the outcome of laparoscopic and retroperitoneoscopic approach for partial nephrectomy in infants and children with duplex kidneys. METHODS: Data of 102 patients underwent partial nephrectomy in a 5-year period using MIS procedures were analyzed. Fifty-two children underwent laparoscopic partial nephrectomy (LPN), and 50 children underwent retroperitoneoscopic partial nephrectomy (RPN). Median age at surgery was 4.2 years. Statistical analysis was performed using χ (2) test and Student's t test. RESULTS: The overall complications rate was significantly higher after RPN (15/50, 30 %) than after LPN (10/52, 19 %) [χ (2) = 0.05]. In LPN group, complications [4 urinomas, 2 symptomatic refluxing distal ureteral stumps (RDUS) and 4 urinary leakages] were conservatively managed. In RPN group, complications (6 urinomas, 8 RDUS, 1 opening of remaining calyxes) required a re-operation in 2 patients. In both groups no conversion to open surgery was reported. Operative time (LPN:166.2 min vs RPN: 255 min; p < 0.001) and hospitalization (LPN: 3.5 days vs RPN: 4.1 days; p < 0.001) were significantly shorter in LPN group. No postoperative loss of renal function was reported in both groups. CONCLUSIONS: Our results demonstrate that RPN remains a technically demanding procedure with a significantly higher complications and re-operation rate compared to LPN. In addition, length of surgery and hospitalization were significantly shorter after LPN compared to RPN. LPN seems to be a faster, safer and technically easier procedure to perform in children compared to RPN due to a larger operative space and the possibility to perform a complete ureterectomy in refluxing systems.

Prolonged CT urography in duplex kidney.

BACKGROUND: Duplex kidney is a common anomaly that is frequently associated with multiple complications. Typical computed tomography urography (CTU) includes four phases (unenhanced, arterial, parenchymal and excretory) and has been suggested to considerably aid in the duplex kidney diagnosi. Unfortunately, regarding duplex kidney with prolonged dilatation, the affected parenchyma and tortuous ureters demonstrate a lack of or delayed excretory opacification. We used prolonged-delay CTU, which consists of another prolonged-delay phase (1- to 72-h delay; mean delay: 24 h) to opacify the duplicated ureters and affected parenchyma. METHODS: Seventeen patients (9 males and 8 females; age range: 2.5-56 y; mean age: 40.4 y) with duplex kidney were included in this study. Unenhanced scans did not find typical characteristics of duplex kidney, except for irregular perirenal morphology. Duplex kidney could not be confirmed on typical four-phase CTU, whereas it could be easily diagnosed in axial and CT-3D reconstruction using prolonged CTU (prolonged-delay phase). RESULTS: Between January 2005 and October 2010, in this review board-approved study (with waived informed consent), 17 patients (9 males and 8 females; age range: 2.5 ~ 56 y; mean age: 40.4 y) with suspicious duplex kidney underwent prolonged CTU to opacify the duplicated ureters and confirm the diagnosis. CONCLUSION: Our results suggest the validity of prolonged CTU to aid in the evaluation of the function of the affected parenchyma and in the demonstration of urinary tract malformations.

Comparison of proximal and distal laparoscopic ureteroureterostomy for complete duplex kidneys in children.

OBJECTIVE: To compare efficacy of proximal and distal laparoscopic ureteroureterostomy (UU) for complete duplex kidneys in children. METHODS: Patients who underwent laparoscopic UU for complete duplex kidneys between December 2016 and July 2022 were reviewed retrospectively. 71 patients who had normal lower pole moiety without vesicoureteral reflux (VUR) were recruited. All of them underwent ultrasound, voiding cystourethrography (VCUG), renal scintigraphy, and magnetic resonance urography preoperatively. Proximal laparoscopic UU was performed in 35 patients and distal laparoscopic UU in 36 patients. Double J stents were placed in normal lower pole moieties. Clinical data, including general information, diagnosis, surgical management, imaging characteristics, clinical symptoms and postoperative complications (classified according to the modified Clavien-Dindo classification), and length of stay were recorded. Measurement date comparisons between groups were performed by t test, counting date were analyzed by chi-square test. RESULTS: The study consisted of 71 patients (56 females and 15 males) with complete duplex kidneys (41 in left kidney and 30 in right kidney). The patients' mean age was 34 m (range 3-161 m) and follow-up ranged from 25 to 81 m. No significant difference was found in age and follow-up time between the two groups. Laparoscopic UU was performed in all patients successfully. The operation time of the two groups was 108.42 ± 26.95 min for distal UU vs 121.46 ± 35.15 min for proximal UU(p = 0.14). No significant difference in postoperative complications was seen between the two groups (22.2% vs 31.4%, p = 0.345). However, in terms of the grading of postoperative complications, the proximal UU group had a higher grade (3 of them had a grade of IV) and more serious complications. CONCLUSIONS: There was no significant difference in the overall incidence of complications between distal and proximal UU. Compared with proximal laparoscopic UU, distal laparoscopic UU is easier to perform with less injury to the peripheral tissues. Postoperative complications of proximal UU are more serious and more difficult to manage. We recommend complete duplex kidney ureteral reconstruction with distal UU.

Bilateral Renal Ectopia-Prenatal Diagnosis.

This report explores the diverse spectrum of congenital anomalies of the kidney and urinary tract (CAKUT), ranging from asymptomatic presentations to the most severe form characterized by bilateral renal agenesis. Genitourinary anomalies, a prevalent subset within this domain, account for a significant proportion, constituting 15-20% of anomalies identified during prenatal screening. An ectopic kidney is defined by the presence of an empty renal fossa and the displacement of the kidney from the lumbar region to alternative locations, with the pelvic region emerging as the most prevalent site. The reported case involves bilateral renal ectopia with unilateral duplex kidney. Initial suspicions of a renal anomaly arose during the first trimester, leading to a definitive diagnosis in the second trimester. The patient underwent regular monitoring every four weeks, ultimately delivering a healthy baby at term. This case underscores the frequency of renal anomalies, emphasizing that a considerable proportion remains asymptomatic. These findings contribute to a broader understanding of congenital renal anomalies, their varied manifestations, and the importance of vigilant prenatal screening for early detection and management.

One Trocar-Assisted Retroperitoneoscopic Ureteroureterostomy for Ureteral Duplication.

Aim: To describe the operative technique and outcome of one trocar-assisted retroperitoneoscopic ureteroureterostomy (OTAU) in 40 cases of complete ureteral duplication in children. Patients and Methods: From September 2016 to December 2020, 40 patients (12 male and 28 female) less than 10 years of age underwent OTAU. A transverse skin incision of 12 mm in length was created approximately 1 cm above the iliac crest. Muscle was spared and retracted with stay sutures to expose the retroperitoneal space. Subsequently, a balloon trocar was then inserted, and pneumoperitoneum was achieved. A 10 mm operating laparoscope (Stema, Germany) with a Maryland was used to dissect and isolate the ureters from surrounding tissues. The ureters were then exteriorized and end-to-side ureteroureterostomy was performed using Polydioxanone (PDS) 6/0 running sutures. Patient's demographic, operative, and follow-up data were collected prospectively. Results: The mean age of patients was 25.2 months (range: 1-105 months). The mean operating time was 81.9 ± 11.3 minutes. There were no intraoperative conversions or complications. After a median follow-up time of 47.5 months, the differential renal function of the pathological upper pole moiety (UPM) was preserved in all patients. Ultrasound revealed a significant reduction in UPM's renal pelvis anterior-posterior diameter from 19.6 ± 9.1 mm preoperatively to 11.1 ± 6.7 mm postoperatively (p < 0.05), accompanied by a reduction in ureter's diameter from 10.8 ± 4.4 mm to 4.8 ± 1.2 mm (p < 0.05). Overall, all 32 patients with preoperative symptoms experienced complete symptom resolution. Conclusion: OTAU is a safe and feasible approach that yields excellent outcomes for complete ureteral duplication.

Risk factor of postoperative adverse events among children with duplex kidney undergoing upper pole heminephrectomy: a single-center experience.

Objective: The aim of this study was to identify the risk factors for postoperative adverse events in children with duplex kidney undergoing upper pole heminephrectomy. Methods: We collected clinical data from pediatric patients with duplex kidney who underwent upper pole heminephrectomy. Based on the presence or absence of postoperative adverse events, the patients were divided into two groups: an adverse events group (n = 16) and a non- adverse events group (n = 37), using multivariate logistic regression analysis to screen for independent risk factors for postoperative adverse events. Results: Through univariate and multivariate analysis, we found that the presence of upper renal ureterocele (P = 0.042, OR = 7.116, 95% CI 1.073-47.172), as well as the presence of accessory renal artery type (P = 0.016, OR = 10.639, 95% CI 1.551-72.978) and other types (P = 0.039, OR = 3.644, 95% CI 0.351-37.836) as the upper kidney's blood supply artery increase the risk of postoperative adverse events, with these differences being statistically significant. Conclusions: In pediatric patients with duplex kidney undergoing upper pole heminephrectomy, the presence of upper renal ureterocele and the presence of accessory renal artery type and other types as the upper kidney's blood supply artery are independent risk factors for postoperative adverse events.

Ectopic Ureter: Spectrum of Magnetic Resonance Imaging Findings.

OBJECTIVE: This study aims to describe the MRI findings of six patients with ectopic ureters in a tertiary care institute. METHODS: A retrospective analysis was conducted on six patients presenting to the Department of Radiodiagnosis at Sawai Man Singh (SMS) Hospital, Jaipur, India, with ectopic ureters. Data were collected from the 3 Tesla (3T) Philips MRI scanner (Koninklijke Philips N.V., Amsterdam, Netherlands) from 2021 to 2023. RESULTS: The mean age was 21.6 years, with an equal male-to-female ratio (1:1). Most patients presented with urinary incontinence (50%, n = 3), followed by abdominal pain. Only 16.6% (n = 1) were associated with a duplex collecting system. In males, the most common site was the seminal vesicle, observed in 66.6% (n = 2), followed by the urethra in 33.4% (n = 1) of cases. One patient with an ectopic opening into the seminal vesicle had Zinner syndrome. In females, the ectopic site was found to be the vagina in all three patients. CONCLUSION: Ectopic ureter is a rare anomaly of the urinary system, often associated with other urinary system anomalies and a few syndromes. Clinical presentations range from the patient being asymptomatic to renal failure; therefore, a high index of suspicion and appropriate imaging are necessary for early diagnosis and timely treatment.

Results of uretero-ureteral anastomosis in pathological duplex kidney.

INTRODUCTION: Duplex renal collecting system or duplex kidney (DK) commonly is associated with uropathy, with upper pole obstruction or lower pole vesicoureteral reflux (VUR). Its management is variable, ranging from therapeutic abstention to total nephrectomy. In case of damage to a single renal pole, uretero-ureteral anastomosis (UUA) is one of the surgical techniques for preserving the pathological pole. It can be performed by laparotomy, laparoscopy, or both. The aims of this study are to report the results of UUA in pathological DK, and compare outcomes depending on the surgical approach. METHODS: This is a retrospective analysis study over 20 years, from April 2002 to July 2022, including all children from 0 to 15 years old who underwent UUA for a DK. Outcome measure included per- and post-operative complications, the occurrence of urinary tract infections and ultrasound measurements during follow-up. RESULTS: Thirty-three children underwent an UUA over 20 years. The median age at diagnosis was 25 days (range: 1 day-12 years). The median age at surgery was 13 months (range: 2 months - 13 years). The sex ratio was 0.22. Prenatal diagnosis was made in 87.9 % of cases (n = 29). The left kidney was affected in 72.7 % of cases. Twenty-seven children (81.8 %) had an ectopic ureteral opening of the upper pole ureter; four children (12.1 %) had ureterocele of the upper pole and 2 children (6.1 %) had vesicoureteral reflux of the inferior pole. UUA was performed by inguinal approach (laparotomy) in 17 children (51.5 %), by laparoscopy in 9 cases (27.3 %), and by laparoscopy combined with laparotomy in 7 cases (21.2 %). The complication rate was 12.1 % (n = 4), including recurrent pyelonephritis with superior polar hydronephrosis (n = 2); iatrogenic injury of the lower pole ureter (n = 1) and a urinoma (n = 1), that all required surgical management with a polar nephrectomy. Between each surgical approach, there were no significant differences in operative time, hospital stay, complications. CONCLUSION: UUA is an effective therapeutic option in duplex kidneys as it allows the preservation of the pathological pole with low complication rates, regardless of the surgical approach.

Prenatal diagnosis and outcomes in fetuses with duplex kidney.

OBJECTIVE: Duplex kidney is a relatively frequent form of urinary system abnormality. This study aimed to elucidate the value of chromosomal microarray analysis (CMA) and whole exome sequencing (WES) for duplex kidney and the perinatal outcomes of duplex kidney fetuses. METHODS: This retrospective cohort study included 63 patients with duplex kidney diagnosed using antenatal ultrasound between August 2013 and January 2023. We reviewed the clinical characteristics, genetic test results, and pregnancy outcomes of the patients. RESULTS: Among the 63 cases based on the inclusion criteria, the CMA detected seven (11.1%) clinically significant variants and nine variants of uncertain significance (VUS), and the pathogenic/likely pathogenic (P/LP) copy number variations (CNVs) in the recurrent region that were associated with prenatal duplex kidney included 17q12, 17p13.3, and 22q11.2. No significant disparity was observed in the CMA detection rate between the unilateral and bilateral groups, or between the isolated and non-isolated groups. WES identified three (50%) P/LP single-gene variants in six fetuses with duplex kidney. We detected the following pathogenic genes in the duplex kidney fetuses: KMT2D, SMPD4, and FANCI. Pregnancy termination in cases where clinically significant variants were detected by genetic testing was different in statistical significance from that in cases with negative results (9/10, 90.0% vs 8/48, 16.7%, P < 0.001). CONCLUSION: This study elucidated the value of CMA and WES for fetal duplex kidney, proving that CMA and WES may be useful tools in prenatal diagnosis and genetic counseling.