Nephroblastoma is a malignant tumour of the kidneys that typically occurs in children, rarely in adults
Containing metanephric blastema, stromal and epithelial derivatives
Characteristic is the presence of abortive tubules and glomeruli surrounded by a spindled cell stroma
The stroma may include striated muscle, cartilage, bone, fat tissue, fibrous tissue
The tumour is compressing the normal kidney parenchyma