Prenatal diagnosis of ectopic kidney: Evaluation of characteristics, additional anomalies and urinary complications.

Objective: To assess the characteristics, additional structural anomalies and postnatal urinary outcome of the cases diagnosed with fetal ectopic kidneys in the prenatal period.

Study Design: Cases having fetal ectopic kidneys, detected from a total of 14,617 pregnant women examined by routine detailed (Group 1) or indicated (Group 2) obstetric ultrasonography (USG) in a tertiary perinatology unit were analyzed. The prevalence of the cases, time of the diagnosis, sidedness of the affected kidney, anatomical location, origins of blood supply, additional urinary or extraurinary anomalies, and urinary complications during the postnatal follow-up period were investigated.

Results: We have detected 33 fetuses with ectopic kidneys in our cohort. The prevalence of fetal ectopic kidney was 0.22 %, with a median (min.-max.) diagnosis time of 21.3 (17.6-34) weeks. In the group in whom indicated USG was performed, the time of diagnosis was later compared to routine detailed USG (p = 0.04) group. There was no difference in terms of gender [male, (n = 14), female (n = 19), p = 0.38] and the sidedness of the ectopic kidneys (p = 0.38). The location of ectopic kidneys was most frequent in the iliac fossa (n = 20, 60.6 %) and in the lateral pelvic areas (n = 13, 39.3 %). The blood supply origin of ectopic kidneys was the common iliac artery in 22 (66.6 %), whereas the aorta in 11 cases (33.3 %). There was an additional urinary anomaly in 8 cases (24 %), an extraurinary structural anomaly, most commonly cardiac, and/or a soft marker for aneuploidy were presented in 16 cases (48 %). The most common urinary complication in the postpartum period was vesicoureteral reflux (n = 5).

Conclusion: Ectopic kidney in the prenatal period is a rare structural anomaly that can equally affect both genders and both kidneys. Prenatal diagnosis is important for the diagnosis of additional anomalies and follow-up of postnatal complications.