Developmental disorders

I./3.2.: Accessory kidneys

The spectrum of accessory kidneys is wide: it can be multiple kidney, complete and partial duality. In complete renal and ureteral duplication the upper ureter is ectopic (it joins medially to the trigonum of urinary bladder below the orthotopic ureter). Ureterokele occurs often on its distal part. The abortive calyx (we must differentiate it from the calyceal diverticulum) and the unicalyceal unipapillary kidney (it is similar to that of the wat, contrary to the normal of appr. 14) – usually cooccurs with many other, for ex. skeletal-vertebral disorders.

US patterns of duplex kidneys: double collecting system above each other separated by a parenchymal bridge (which can be cambered inward, too, the longitudinal diameter of the kidney is longer than one of the normal kidney. The upper renal pole is usually comprimated, thus it can be confused with space occupying lesions on intravenous urography (IVU). MRI is highly appropriate to clarify the occurance of a double collecting system. Vesicoureteral reflux often occurs in the lower pole of the ureter (isotope, or contrast enhanced US examinations).