Giant Hydroureteronephrosis Associated with Primary Obstructed Megaureter

The case is presented of a four year old boy with a large left abdominal mass. The patient was diagnosed as having a left giant hydroureteronephrosis due to a primary obstructed megaureter, based on the findings of ultrasonography, micturating cystourethrography, excretion urography, computed tomography and percutaneous antegrade pyeloureterography. Diuretic renography showed that the obstruction was partial. Since a static renal scintigram indicated that renal function on the affected side was moderately well preserved, ureteroplasty is planned.