The outcome of prenatally diagnosed renal tumors

PURPOSE: We assessed the incidence of perinatal morbidity and evaluated the outcome in children with prenatally diagnosed renal tumors in a retrospective multicenter study. MATERIALS AND METHODS: A review of the records of patients from 20 institutions identified 28 children with prenatally diagnosed renal tumors. Prenatal findings, clinical charts, and radiological, surgical and pathological reports were reviewed in this study. RESULTS: There were 26 congenital mesoblastic nephromas and 2 Wilms tumors. One or more complications were identified in 20 of the 28 cases (71%) during the perinatal period. Polyhydramnios was observed in 11 fetuses (39%), 2 presented with hydrops fetalis and 7 presented in acute fetal distress requiring emergency cesarean section, of which 1 died in utero before delivery. Median gestational age of the 27 neonates born alive was 35 weeks (range 29 to 39), including 13 (46%) who were pre-term (less than 34 weeks of gestation). Complications at birth included hemodynamic instability in 3 newborns, of whom 2 underwent emergency surgery, respiratory distress syndrome in 8 (30%) and hypertension in 6 (22%). Surgical complications occurred in 7 patients (26%), including tumor rupture in 1 and intraoperative bleeding with postoperative death in 1. At a median followup of 42 months (range 2 to 105) 26 of the 27 children were in complete remission. CONCLUSIONS: Fetal renal tumors have an excellent oncological outcome but a high risk of perinatal complications. Prenatal diagnosis should allow planning the delivery at a pediatric tertiary care center to avoid a potentially life threatening condition in neonates in the first hours of life.