Imaging of Wilms' tumor: what is important!

The imaging of Wilms' tumor needs to be quite focused so that the oncologist and surgeon can most precisely stage the patient before operation. The imager needs to be exact about the extent of the primary tumor and define any invasion into the adjacent soft tissues. The ability to detect nodal disease is quite difficult but clearly influences the preoperative approach and staging. Children with large tumors extending across the midline in whom primary resection may lead to tumor spillage are prime candidates for preoperative chemotherapy, and the imager has significant input in making this decision. The imager must define metastases in the lungs and the liver and evaluate the risk of bilateral tumor (particularly metachronous) by searching the index kidney for multifocal lesions or nephroblastomatosis in either kidney.