Nephroblastoma (Orphanet_654) is an embryonal neoplasm characterized by the presence of epithelial, mesenchymal, and blastema components. The vast majority of cases arise from the kidney. A small number of cases with morphologic features resembling Wilms tumor of the kidney have been reported arising from the ovary and the cervix. Also known as: Wilms tumor, Wilms tumor (nephroblastoma), Wilms' tumor.