Veno-renal anomalies constitute a heterogeneous group of rare congenital malformations with significant diagnostic and surgical implications. Among them, retrocaval ureter, duplication of the inferior vena cava (IVC), and congenital solitary kidney are individually uncommon, and their concurrent occurrence is exceptionally rare. Retrocaval ureter, also termed Circumcaval ureter or Preureteral vena cava, arises from persistence of the right posterior cardinal vein, which develops into the infrarenal IVC located anterior to the ureter. (1,2) This anomalous course produces varying degrees of obstruction, with an incidence of approximately 1 in 1000 individuals, typically presenting in the third or fourth decade and showing male preponderance. (2,3) Duplication of the IVC, reported in 0.2–3% of autopsy series, results from persistence of both supracardinal veins. (1) While often asymptomatic, failure to recognise this anomaly may complicate vascular, retroperitoneal, or transplant surgery. (1,3) Congenital solitary kidney, occurring 1 in 1000–2000 live births due to renal agenesis or aplasia, is generally silent but obstruction of the solitary unit poses grave risk. We describe a young woman with this unique triad, successfully managed by laparoscopic ureteric reconstruction.

A 23-year-old woman presented with a two-week history of sudden-onset, dull aching right flank pain. She denied fever, chills, hematuria, vomiting, or urinary symptoms, and had no prior history of surgery, comorbidity or trauma. On examination, she was afebrile, alert, and haemodynamically stable. Abdominal assessment revealed right costovertebral angle tenderness without palpable fullness or mass, while systemic examination was otherwise unremarkable. Laboratory investigations showed Haemoglobin 11.8 g/dL, Total leukocyte count 9,800/cu.mm, and Platelets 2.1 lakhs/cu.mm. Renal function was preserved with Blood urea 21 mg/dL and Serum creatinine 0.77 mg/dL. Electrolytes and urinalysis were normal. Ultrasonography demonstrated non-visualisation of the left kidney, compensatory hypertrophy of right kidney measuring 13.2 × 4.9 cm with a cystic lesion in the renal pelvis measuring 5.3 × 4.1 cm, likely representing an extrarenal pelvis. Corticomedullary differentiation was preserved, and no calculi or significant hydronephrosis were observed. The bladder and remaining abdominal organs were unremarkable. Contrast-enhanced CT KUB revealed three distinct anomalies: (i) Solitary hypertrophied Right kidney, (ii) Right sided Proximal ureter coursing posterior to the infrarenal IVC (Figure.1A) and (iii) Duplication of the infrarenal IVC with confluence 4 cm above the iliac bifurcation. Mild hydroureteronephrosis noted with ballooning of renal pelvis and extra-luminal compression of right proximal ureter (Figure.1B) were evident. Given symptomatic obstruction in the solitary kidney, surgical management was indicated. Retrograde pyelography confirmed the classical “fish-hook” deformity, diagnostic of retrocaval ureter (Figure.2A,2B). Laparoscopic transperitoneal ureteric resection with uretero-ureterostomy was performed under general anaesthesia. Intraoperatively, duplicated infrarenal IVC with two venous channels was identified, with the right ureter traversing between them and a dilated extrarenal pelvis (Figure.2C). The gonadal vein drained into the anomalous venous branch. The retrocaval segment was excised, and a tension-free uretero-ureterostomy was completed over a 6 Fr double-J stent (Figure.2D). Dissection was meticulous, and blood loss was minimal. Abdominal drain was placed adjacent to anastomotic site to monitor for anastomotic leak post-operatively. Postoperative recovery was uneventful. Abdominal drain was removed on 3rd Postoperative day, Foley catheter at 1 week, and the patient was discharged with the stent in situ, which was removed at four weeks. At three months, CT venography confirmed persistence of the duplicated IVC, a patent straightened ureter, mild residual hydronephrosis of the right kidney. Renal function remained stable, and the patient was asymptomatic.

This case illustrates the concurrence of three rare congenital anomalies: duplicated infrarenal IVC, retrocaval ureter, and congenital solitary kidney. While each anomaly has been described in isolation, their coexistence in a single patient is exceptional and carries significant clinical and surgical implications. Retrocaval ureter results from persistence of the right posterior cardinal vein, which forms the infrarenal IVC anterior to the ureter, thereby displacing the ureter dorsally and producing obstruction.(1,4) Duplication of the IVC arises from failure of regression of the left supracardinal vein, leading to two venous channels flanking the aorta.(1,4) Congenital solitary kidney, meanwhile, reflects failure of ureteric bud induction or metanephric blastema development, resulting in unilateral renal agenesis or aplasia. Obstruction in the setting of a solitary kidney poses imminent risk to the only functional renal unit, necessitating prompt diagnosis and surgical intervention.(3) Duplication of the IVC, although usually asymptomatic, assumes clinical importance when unrecognised, as it predisposes to catastrophic venous injury during nephrectomy, adrenalectomy, vascular reconstruction, or transplantation.(1,4) It may also complicate endovascular procedures such as IVC filter placement, venous bypass, or retroperitoneal oncological surgery, where incomplete recognition of venous anatomy can have fatal consequences. Contrast-enhanced CT urography remains the investigation of choice, simultaneously delineating ureteric anatomy, degree of obstruction, and associated vascular anomalies. (1,4) MRI urography offers comparable accuracy without radiation exposure and is especially useful in young patients or for serial follow-up. Retrograde pyelography retains value as a confirmatory test, demonstrating the characteristic “fish-hook” deformity pathognomonic of retrocaval ureter. (2,3) Importantly, accurate radiological interpretation prevents misdiagnosis of anomalous venous structures as retroperitoneal masses or lymphadenopathy. All symptomatic retrocaval ureters with the preserved renal function warrant surgical correction. (2,3,5) Laparoscopic transperitoneal repair is currently favoured, providing ample working space, ergonomic access for intracorporeal suturing, and reduced morbidity compared to open or retroperitoneoscopic approaches. (5) The essential principle involves excision of the retrocaval segment and re-anastomosis of the ureter anterior to the IVC in a tension-free manner. In our patient, meticulous intraoperative recognition of the duplicated IVC was crucial to avoid venous injury, and postoperative recovery was uneventful with preserved renal function. Only isolated reports describe retrocaval ureter with duplicated IVC, and even fewer document additional solitary kidney. Most patients present in adulthood with flank pain, recurrent infections, or progressive hydronephrosis. Laparoscopic repair consistently yields excellent outcomes. This case contributes to the limited literature by highlighting the unique surgical considerations of addressing obstructive uropathy in a solitary kidney complicated by dual IVC channels. In summary, thorough preoperative radiological evaluation and tailored surgical planning are indispensable in patients with complex veno-renal anomalies to optimise outcomes and avert catastrophic complications.

1. Kellman GM, Alpern MB, Sandler MA, Craig BM, Seigel RS, Rosenfield AT, et al. Computed tomography of vena caval anomalies with embryologic correlation. Radiographics. 1988;8:533-56. 2. Crosse JE, Soderdahl DW, Teplick SK, Holms F, Strano A, Swanson DH, et al. Nonobstructive circumcaval (retrocaval) ureter: Report of 12 cases. Radiology. 1975;116:69-71. 3. Carrion H, Gatewood J, Politano V, Morillo G, Lynne C, Kim H, et al. Retrocaval ureter: Report of 8 cases and the surgical management. J Urol. 1979;121:514-7. 4. Kim SS, Shin HC, Hwang JA, Jou SS, Lee WH, Choi SY, et al. Various congenital anomalies of the inferior vena cava: Review of cross-sectional imaging findings and report of a new variant. Abdom Radiol (NY). 2017;42:2890-905. 5. Simforoosh N, Nouri-Mahdavi K, Tabibi A, Basiri A, Ziaee SA, Pourreza F, et al. Laparoscopic pyelopyelostomy for retrocaval ureter without excision of the retrocaval segment: First report of 6 cases. J Urol. 2006;175:2166-9.