Crossed fused renal ectopia: Diagnosis and prognosis as a single-center experience

Crossed fused renal ectopia (CFRE) is a rare congenital malformation. Renal bladder ultrasound (RBUS) is a good tool for establishing the diagnosis, however, additional imaging with a voiding cystourethrogram (VCUG) and dimercaptosuccinic acid scan (DMSA) might be required. We assessed the need for postnatal evaluation and the long-term consequences in patients with this diagnosis.

A retrospective review of the records of all patients diagnosed with CFRE between 2004 and 2014 was done. We included all patients who underwent postnatal evaluation with RBUS, DMSA and VCUG. Long-term radiological and functional outcomes were assessed.

A total of 29 patients with CFRE were identified. Majority of cases were detected antenatally (79%) and left to right crossed ectopia constituted the majority of cases (65%). RBUS revealed associated hydronephrosis (HN) in 11 patients (38%). DMSA scans confirmed the diagnosis in all patients and showed impaired renal function in 10 ectopic kidneys (34%). Vesicoureteral reflux was detected in 12 patients (41%); one third of them needed surgical intervention. Extra-urinary anomalies were present in 14 patients (48%) mainly of cardiac origin. After a mean follow-up of 4.5 years, 4 patients (14%) with extra-urinary anomalies developed chronic kidney disease and two of them died.

Crossed fused renal ectopia is commonly associated with both urinary and extraurinary malformations. Postnatal RBUS is usually sufficient for diagnosis, however, additional imaging may aid for confirming the diagnosis and detection of associated urinary anomalies. Presence of extra-urinary malformations with crossed fused ectopia carries a higher risk of morbidity.

Retrospective study [diagnostic/prognostic study].

Level IV.