Congenital giant hydroureteronephrosis.

Four patients with giant hydroureteronephrosis are reported to emphasize the massive proportions attained by a dilated ureter. Ureteral obstruction was congenital in each case; duplication with ectopic insertion was present in three of the four patients. In three patients the massively dilated ureter caused partial obstruction of the contralateral ureter. If ultrasound and/or computed tomography demonstrate a huge, septate, cystic structure crossing the midline, massive megaureter should be suspected. Antegrade puncture can be used to confirm the diagnosis.