The incidence of associated urological abnormalities in children with renal ectopia

PURPOSE: We evaluate the incidence of associated urological abnormalities in children with renal ectopia (RE). MATERIALS AND METHODS: We retrospectively reviewed database records of 99 consecutive pediatric cases of RE diagnosed at our hospital between 1988 and 2001. RESULTS: Mean patient age at diagnosis was 13 months (range 0 to 9 years, SD 2.2 years). Twenty children were evaluated for symptoms, while the remainder were asymptomatic and evaluated after prenatal or postnatal ultrasound finding of RE. There were 10 cases of crossed renal ectopia and 89 cases of simple renal ectopia (S-RE), of which 82 were unilateral and 7 bilateral. The most frequent associated urological abnormality was vesicoureteral reflux (VUR), which was present in 20% of patients with crossed renal ectopia and 30% with S-RE. In patients with bilateral S-RE the incidence of VUR increased to 71%. In patients with unilateral S-RE VUR involved the orthotopic kidney in more than 85% of the cases. Moreover, technetium dimercapto-succinic acid scans documented primitive reduction of function of the ectopic kidney in 87% of the unilateral S-RE cases. Other associated urological anomalies were present in 14% of patients, the most frequent of which were contralateral renal dysplasia (4%), cryptorchidism (5%) and hypospadias (5%). CONCLUSIONS: A high proportion of children with renal ectopia have associated urological anomalies, and VUR is the most common. The presence of VUR in the normally positioned kidney together with decreased function of the ectopic kidney might predispose these children if not recognized and treated to renal function impairment.