Teratoid Wilms' tumor: a case report.

Teratoid Wilms' tumor is rarely seen and is a description used only recently. The term describes classical nephroma with a diversity of cell types and tissues. In this reported case, the epithelial component consisting of squamous areas made up 70 percent of the tumor; no criteria of dysplasia nor any nephroblastomatosis areas or endodermal elements were presented. Although it is reported that teratoid Wilms' tumor is not usually aggressive or metastatic, a case of unilateral teratoid Wilms' tumor in a 2.5-year-old-boy who died because of metastatic disease is presented and the literature reviewed.