[Mesoblastic nephroma. Apropos of 6 cases]

6 cases of congenital mesoblastic nephroma removed surgically between 5 days and 2 months 1/2 of age are reported. The authors point out the peculiar histological aspect of this tumor : myomatous or fibromyomatous proliferation which surround in some places normal or dysplastic glomerular or tubular structures and penetrates by digitations in parenchymatous elements without destroying them. At the periphery of the tumor there are some lymphatic capsular ectasia or lymphoid infiltration or cartilaginous islets. In case of a renal tumor of the newborn or infant they emphasize the necessity to search for a congenital mesoblastic nephroma in order to avoid all types of radio therapic or chimiotherapic treatment without histological diagnosis. These forms of therapy are responsible for severe complications heavily impairing a prognosis which in most cases is an excellent one when nephrectomy alone is carried out. In some exceptional cases it seems useful to add other forms of therapy when the tumor proves itself to be of a peculiar aggressivity macro or microscopically.