[Gigantic pyohydronephrosis and contralateral ureteral bud. Problems of differential diagnosis].

Both giant hydronephrosis and blind-ending ureteral bud are rare conditions. We report on a patient with an impacted ureteral stone leading to giant pyohydronephrosis (6.51) on the right side, which in turn caused displacement of the ureter containing the stone to the left. An asymptomatic blind-ending ureteral bud initially complicated the diagnosis. After nephrectomy, a unsuspected transitional cell carcinoma of the right renal pelvis and the ureter was found.