Wilms tumor (WT) is one of the most common solid tumors of childhood, occurring in 1 in 10,000 children and accounting for 8% of childhood cancers. It is believed to result from malignant transformation of abnormally persistent renal stem cells which retain embryonic differentiation potential. The risk of Wilms tumor is increased in association with several recognizable congenital malformation syndromes, although these cases account for less than 5% of all clinical patients with Wilms tumor.
Synchronous bilateral Wilms tumor occurs in about 5% of all patients with Wilms tunors. Patients with synchronous bilateral Wilms tumor are known to present at younger age than those with unilateral Wims tumor. Whereas nephrectomy has remained the mainstay of treatment for patients with unilateral Wilms tumor, this is not true for bilateral cases. Patients with bilateral Wilms tumor pose a complex therapeutic problem, and the emphasis is currently on maximal preservation of functioning renal parenchyma. The role of preoperative chemotherapy is now well-established in the management of patients with synchronous bilateral Wilms tumor.
Germline mutations cause less than 5% of Wilms tumors; most of the cases are sporadic. However, numerous instances of multiple sibs with Wilms tumor have been described. Several genes or chromosomal areas have been associated with the development of WT: WT1 at 11p13 (WT1 gene), WT2 at 11p15, WT3 at 16q, WT4 at 17q12-q21, WT5 at 7p14 (POU6F2 gene), and WT6 at 4q12 (REST gene). BRCA2 gene variants have also been reported in WT patients.