Crossed Fused Renal Ectopia with Separate Collecting Systems and Functional Obstruction Treated with a Novel Common Sheath Pyeloplasty: A Case Report

Abstract

Background: Cross-fused renal ectopia (CFRE) is a rare congenital anomaly involving abnormal renal fusion and positioning, with an estimated occurrence of 1 in 1000 live births. Most patients remain asymptomatic, but complications such as hydronephrosis, urinary tract infection, or pelvi-ureteric junction obstruction (PUJO) can develop. Functional obstruction without mechanical narrowing is exceptionally uncommon. We report a case of a 2-year-old boy with CFRE and functional PUJO who was managed with a novel dismembered common sheath pyeloplasty, with a satisfactory outcome. Case Presentation: We report a 2-year-old male who presented with recurrent fever, progressive abdominal swelling, and abdominal pain since birth. Antenatal scans revealed an ectopic kidney. Examination showed a central cystic abdominal mass and a non-palpable right testis. Ultrasonography demonstrated bilateral ectopic pelvic kidneys with marked right hydronephrosis. Computerised Tomographic (CT) urography revealed cross-fused renal ectopia draining into a massively dilated renal pelvis with the "fountain sign." Laboratory investigations were normal. The patient underwent a novel common sheath dismembered pyeloplasty and right orchidopexy. The patient had an uneventful recovery. The drain and catheter were removed on postoperative days 8 and 10, respectively. He was subsequently discharged on postoperative day 12 and remains asymptomatic on follow-up. Conclusion: Cross-fused renal ectopia can rarely present with hydronephrosis due to functional obstruction. Advanced imaging is essential for accurate diagnosis. Dismembered common sheath pyeloplasty remains a successful reconstructive option of the anomalous systems of cross renal ectopia, representing a novel modification of the procedure described by Anderson and Hynes.