Nephromegaly in infancy and early childhood: A risk factor for Wilms tumor in Beckwith-Wiedemann syndrome

Objective: Beckwith-Wiedemann Syndrome (BWS) is an overgrowth syndrome associated with macrosomia, omphalocele, macroglossia, visceromegaly and Wilms tumor (WT). We conducted a case-control study in children with BWS to examine whether nephromegaly increases the risk of WT. Methods: The BWS Registry was used to identify control and case patients. Control patients were defined as children with BWS who were older than 6 years and had no imaging evidence of renal disease or previous WT and for whom complete records were available; 31 patients met these criteria. Case patients were defined as children with BWS who had WT and screening renal imaging before the diagnosis of WT; 12 of these patients had serial screening images before diagnosis of WT and comprised the study population. Only renal images obtained before the diagnosis of WT was made were used to assess renal length. Results: All 12 patients with WT had nephromegaly (greater than or equal to 95th percentile of age adjusted renal length) on serial screening studies. Only four of 31 control patients (specificity = 86%) had nephromegaly resulting in an odds ratio of 72 (95% confidence interval = 13-391) for the risk of WT with nephromegaly. Conclusions: In patients with BWS, persistent nephromegaly is a strong risk factor for the development of WT. If screening for WT is done in this population, infants with nephromegaly should be considered those at greatest risk for WT, and screening may be best targeted at this group.