CASE Report: Misdiagnosed Solitary Crossed Ectopic Kidney with Ureteropelvic Junction Obstruction Complicating Pregnancy

By: Neeraj K. Goyal, MCh; Sangeeta Goel, DGO, DNB, MPH; Apul Goel, MS, MCh, DNB, MNAMS | Posted on: 01 May 2021

Solitary crossed renal ectopia is a rare entity.1 Most of the crossed ectopic kidneys are incidental findings unless malrotation affects its excretory ability. We present a case of solitary crossed renal ectopia with uretero-pelvic junction obstruction (UPJO) that was confused with a twisted ovarian cyst in a 24-weeks pregnant woman leading to maternal morbidity and fetal mortality. This case highlights several learning points regarding surgical misadventure and describes the approach to the management of such complex cases that needs to be individualized according to the situation.

Figure 1. (a) CT-urogram confirmed presence of solitary right ectopic kidney. (b) antegrade nephrostogram through percutaneous nephrostomy that showed transversely placed right ectopic kidney at pelvic brim with complete block and contrast entering ureter. (c) simultaneous antegrade pyelogram and retrograde ureterogram, performed at time of surgery showing blind ending left ureter (black arrow) crossing to right side at mid sacral level and 1.5 cm gap between renal pelvis and proximal end of ureter.
Figure 2. Intraoperative picture showing spatulated ureter (with Double-J stent in situ) being anastomosed using flap (black arrow) of renal pelvis.
Figure 3. (a) postoperative plain X-ray film confirmed position of Double-J stent. (b) followup excretory urography at 1-year confirmed dependent and widely patent ureteopelvic junction with free drainage of contrast to bladder.

A 25-year-old, 24-weeks pregnant woman presenting with acute abdomen was operated for a cystic mass on ultrasonography that was suspicious of adnexal/ovarian cyst torsion in a peripheral hospital. The sonologist also commented on the possible absence of kidneys in their normal location but could not identify their location. Intraoperatively, a cystic mass in the pelvis was partially excised, with the exact nature unknown. Postoperatively, the woman had anuria with 1.5 liters/day of drain output that increased on furosemide administration. She was referred to us in poor condition, with fever, anuria and serum creatinine 3.9 mg%. Ultrasound of the abdomen showed bilateral empty renal fossae, a solitary pelvic kidney and free fluid in the peritoneum. Ultrasound-guided nephrostomy was placed leading to normalization of renal functions. Meanwhile, the woman had preterm labor delivering a dead fetus.

After 4 weeks, computerized tomography (CT)-urography confirmed a solitary ectopic-pelvic kidney (fig. 1, a). Simultaneous antegrade pyelogram and retrograde ureterogram confirmed a 1.5 cm gap between the renal pelvis and proximal ureter (fig. 1, b and c). A final diagnosis of left-to-right solitary crossed-renal ectopia with uretero-pelvic disruption was reached. Open uretero-pyelostomy using renal pelvis flap was performed over a 5F Double-J stent (figs. 2 and 3, a). At 8-year followup the woman is asymptomatic with normal renal function and unobstructed drainage, as documented by renal scan and excretory urogram (fig. 3, b).

Acute abdomen is one of the most challenging diagnostic and therapeutic dilemmas in pregnancy.2,3 Investigations, including ultrasonography and magnetic resonance imaging, have limitations and may remain inconclusive.4,5 The patient probably had a renal colic because of UPJO that was misdiagnosed as acute abdomen. CT scan and nephrostogram images show a truncated renal pelvis that can be explained by the fact that the renal pelvis was probably partially excised accidentally (fig. 1).

This case highlights the surgical misadventure leading to maternal morbidity and fetal mortality and has several valuable teaching points. As a rule, if a kidney is not seen in its normal location, then the diagnosis of agenesis/ectopia must be considered on initial sonography.

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