Imaging of nephroblastomatosis: an overview.

Nephroblastomatosis is an abnormality of nephrogenesis characterized by incomplete maturation of primitive nephrogenic cells. The resultant individual lesions have variable histologic findings and distribution in the kidney. There is wide acceptance of nephroblastomatosis as a precursor lesion to Wilms tumor. Consequently, the role of imaging in assessing patients for neoplastic transformation of nephroblastomatosis should be emphasized. Computed tomography (CT) has been shown to be superior to ultrasound (US) in this regard. Nonetheless, the low cost and lack of radiation of US make it attractive for serial screening studies. Although magnetic resonance imaging shows promise in assessment of the kidney for nephrogenic rests, experience is limited in its use in evaluating patients for nephroblastomatosis. The authors present protocols for assessing patients identified as being at either high or low risk for the development of Wilms tumor due to nephroblastomatosis. These protocols take into account the advantages of CT and US. Scanning intervals are determined from epidemiologic data on the occurrence of Wilms tumor; the most intense screening occurs during the younger ages of life, when the likelihood of Wilms tumor development is highest.