Understanding Ectopic Kidneys: Insights from a Single-Center Study

Introduction: The failure of the normal ascent of the kidney can result in ectopic kidneys (EK) and fusion anomalies. EKs are often accompanied by urological and extrarenal abnormalities. This study aims to provide a comprehensive overview of EKs, associated renal and extrarenal anomalies, and kidney functions among patients with simple and cross ectopic kidneys. Materials and Methods: Clinical records of patients diagnosed with EK admitted to the pediatric nephrology unit between June 2017 and June 2022 were retrospectively evaluated. Results: In this study, 41.20% (n: 61) of patients had crossed ectopic (CE) kidneys. The most common type of crossed ectopia was inferior CE (n:33 56.9%). The most frequent presenting features were an empty renal fossa (7.40%, n: 11). During the first evaluation, 18.91% (n:28) of patients had hydronephrosis, most of which were mild (SFU 1-2). Vesicoureteric reflux (VUR) was evident in 7.4% of patients. The mean DMSA (dimercaptosuccinic acid) uptake was lower in EK (40.37 +/- 7.31) compared to orthotopic kidneys. Comparison of simple and CE kidneys showed similar results regarding the presence of hydronephrosis, vesicoureteral reflux (VUR), and differential function of EKs. In both groups, serum creatinine levels and estimated glomerular filtration rate (eGFR) were preserved. Conclusion: Patients with ectopic kidneys often present with renal and extrarenal anomalies. Although hydronephrosis is a common occurrence, it is usually mild and transient, and incidence of vesicoureteral reflux is low. Considering the preservation of renal function in mid-term period, it may be more appropriate to evaluate each patient's need for a complete urological examination on a case-by- case basis.