Unilateral Renal Agenesia

Definition and Epidemiology of Unilateral Renal Agenesia

The unilateral renal agenesis is the complete absence of a renal system or parts of it on one side, with a normal kidney on the opposite side. The prognosis is good; in contrast to bilateral renal agenesia, which is rare and always fatal, see Potter's syndrome.

Epidemiology: 1:1100 to 1:5000. Slightly more common on the left side. Male to female = 2:1.

Causes (Etiology) of Renal Agenesia

Unilateral absence of the ureteric bud or a hindered ureteral development are most often the cause for renal agenesis. Depending on the timing of embryological disturbance, associated malformations of the genital organs are possible, since the ureteric bud and genital organs have a common anlage (Wolffian duct).

Pathology, Signs and Symptoms of Unilateral Renal Agenesia

Malformations of the upper urinary tract:

The ureter is completely missing in 50% of patients, in the other cases the rudiments of the ureter are present. Possible pathological findings of the contralateral side: vesicoureteral reflux (28%), ureteropelvic-junction obstruction (7%).

Malformation of the genital organs:

Malformation of the genital organs are common (20–50%). In men, lack of ipsilateral vas deferens, seminal vesicles and/or ejaculatory duct. In females, uterus unicornuatus or rudimentary system of the ipsilateral side in uterine bicornuatus, hydro-/hematocolpos.