Crossed renal ectopia: can it be a diagnostic problem?

Crossed renal ectopia (C-RE) is a rare congenital anomaly in which both kidneys are located unilaterally. The crossed kidney is situated on the side opposite to its ureteral orifice and usually lies below the normal kidney. The frequency of this malformation is estimated at 0.05% to 0.1%. Most of the patients remain asymptomatic. In other cases C-RE is diagnosed incidentally on routine ultrasonography, due to the presence of unspecific symptoms. The diagnosis of C-RE is possible due to a wide range of imaging techniques: US, IVU, CT, MRI, and TcDMSA scan. Among them IVU, CT, and MRI have the highest degree of confidence. The aim of this retrospective study was to present our own experience with 5 children affected with C-RE, emphasizing the differences in clinical picture and low sensitivity of ultrasound images. In all of them the final diagnosis was established by IVU or MRI.