Neonatal Wilms tumor.

Neonatal renal tumors are very rare. We have identified 15 cases of Wilm's tumors diagnosed in the first 30 days of life. The most common presentation was an abdominal mass on routine newborn examination, and three tumors were noted on an antenatal ultrasound. All of the infants underwent primary excision of the tumor. Five infants were not given postoperative chemotherapy after surgical excision. One of these children had a relapse and later died of progressive disease. The remaining children are alive at a median follow-up of 31 months. Eight of the tumors had evidence of nephrogenic rests. More frequent follow-up physical and imaging examinations are indicated in children not given adjuvant chemotherapy or whose tumors show nephrogenic rests.