Neuroglial tissue in partially cystic Wilms' tumour

Wilms' tumour (nephroblastoma), the commonest malignant renal tumour of childhood, is thought to be derived from metanephric blastema and a majority of cases show the classical triphasic pattern of blastema, stroma and epithelium. There is usually little difficulty in making a correct histological diagnosis, but problems can arise due to the extraordinary potential of metanephric blastema to differentiate into a wide variety of heterologous tissues. Here we report, probably for the first time, two cases of Wilms' tumour which contained prominent quantities of neuroglial tissue. The classification of these cases as Wilms' tumours rather than renal teratomas is discussed.