[Bilateral Wilms tumor].
The incidence of bilateral involvement it is generally estimated to be 5% to 10%. It shows association with certain congenital anomalies and it has an increased occurrence of familial cases. The records of 9 children (5 boys, 4 girls) diagnosed at Vall d'Hebron Hospital with bilateral Wilms tumor between 1976-1995 were analyzed. Six patients had synchronous tumors and 3 had metachronous lesions. Genitourinary malformations were present in 4 children and another had hemihypertrophy. Two children were brothers. Eight patients underwent pre-operative radiation therapy and/or chemotherapy. Five patients had nephrectomy on one side (3 of them had metachronous presentation) and partial nephrectomy on the other side. The other children had bilateral partial nephrectomy or tumorectomy. Seven out of the nine patients are alive (78%). The two children who died presented with stage IV tumors and high grade malignant. One boy suffers cardiomyopathy. All survivors have normal renal function. With the proven efficacy of chemotherapy, bilateral renal salvage procedures were demonstrated to be effective in controlling disease without compromising renal function or survival. The innovative approaches developed for the treatment of bilateral Wilms tumor may influence the treatment of unilateral Wilms.