Prenatal puncture of a unilateral hydronephrosis leading to fetal urinoma and postnatal nephrectomy.

Fetal pelvicaliceal dilatation due to ureteropelvic junction obstruction is the most common cause of antenatal hydronephrosis; it rarely leads to a spontaneous rupture resulting in urinoma formation. Antenatal intervention has been recommended only in those cases of large urinomas that seem to interfere with the function of other organ systems (eg, pulmonary hypoplasia secondary to diaphragmatic elevation). We report the case of a fetal intervention (transuterine puncture) in a unilateral massive hydronephrosis leading to a perirenal urinoma and the preterm birth of a female infant. Postnatally, mechanical ventilation and oxygen were required, as was forced percutaneous urinoma drainage. Evaluation revealed a fistula formation between the perirenal space and the kidney's collecting system, possibly due to the fetal intervention. Unfortunately the kidney function was very poor, and surgery to remove the impaired kidney and the urinoma was performed. We discuss the possible effects of fetal intervention in cases of obstructive uropathy and the postnatal risks associated with it.