[Experimental models of embryonic nephroblastomas (Wilms' tumor)]

Histological structure and histochemical characteristics of renal tumours induced in rats either by N-nitrosodimethylamine (DMNA) or N-nitrosoethylurea (NEU) are described. The rats treated with oral administration of DMNA developed 1 nephroblastoma and 176 mesenchymal tumours similar to mesoblastic nephroma. In rats receiving the transplacental treatment with NEU 24 mesenchymal tumours and 5 nephroblastomas corresponding to the epithelial variant of human Wilms' tumour occurred. Histologic and histochemical findings show that the mesenchymal neoplasms contain the epithelial component in the form of preexisting renal tubules. These tubules are similar to those of the normal kidney and strongly differ from the primitive tubular structures of embryonic rat kidneys and nephroblastomas.