[Renal tumors in children.  A single center study of 31 cases]. 
In order to illustrate epidemiologic features and survival rate, 31 Wilm's tumours treated in our institution have been retrospectively studied.  The mean age at diagnosis in our series was surprisingly higher than usually described: 25% of the patients were older than 8 years.  Moreover, a mesoblastic nephroma congenital kidney tumour--appeared in a 10 month old girl.  Symptoms were usually abdominal mass or gross hematuria.  Young children are often brought to medical attention because of abdominal swelling: a large flank mass was palpable in all children under 5 years.  Our study shows that preoperative chemotherapy results in a less intensive treatment regimen conducting probably to less sequellae.  Event free survival and overall survival were respectively 87% and 94% at 10 years after diagnosis.  Renal insufficiency was the most important side effect: 2 children required renal transplantation.