title: [Renal tumors in infants aged less than 1 year].
abstract: OBJECTIVE
  To determine the frequency and distribution of primary renal tumors diagnosed in a pediatric oncology unit in children younger than 1 year and identify their clinical and histopathological characteristics, the treatment used, and outcomes.
  
  
  METHODS
  We retrospectively reviewed the medical records of infants with primary tumors of the kidney diagnosed between January 1972 and February 2003.
  
  
  RESULTS
  A total of 137 tumors were diagnosed in our unit during the period studied. Of these, 25 (18.2 %) occurred in infants aged less than 1 year. There were 17 boys and 8 girls. The most prevalent tumor in this age group was Wilms' tumor (WT) in 15 patients, followed by mesoblastic nephroma (MN) in 9 patients and rhabdoid tumor in 1 patient. The mean age at diagnosis of WT was 4.8 months (range: 1 day-11 months), with a median of 5.03 months. The median age at diagnosis of MN was 1 day (range: 1 day-3 months). Presenting symptoms consisted of abdominal mass in 20 patients, hematuria in 4 patients and intestinal pseudo-occlusion (MN) in 1 patient. High blood pressure was found in 12 of the 25 patients. Among the 15 WT, 9 were stage I, 1 was stage II, one was stage III, 2 were stage IV, and 1 was stage V. One patient died before surgery. Overall survival at 5 years was 0.67 (SE 0.12) for WT and 0.89 (SE 0.1) for MN, respectively, with a mean follow-up of 290 months.
  
  
  CONCLUSIONS
  MN was more frequent than WT in infants aged less than 6 months. The first-line therapy in these patients is surgery since this type of tumor shows little chemosensitivity and chemotherapy is poorly tolerated in infants.
authors.affiliation: Unidad de Oncología Pediátrica, Hospital Universitario La Fe, Valencia, España. jubagui@wanadoo.es
authors.forename: J
authors.initials: J
authors.lastname: Balaguer Guill
authors.forename: J Maria
authors.initials: JM
authors.lastname: Fernández Navarro
authors.forename: A
authors.initials: A
authors.lastname: Cañete Nieto
authors.forename: Maria D
authors.initials: MD
authors.lastname: Muro Velilla
authors.forename: M
authors.initials: M
authors.lastname: Hernández Martí
authors.forename: V
authors.initials: V
authors.lastname: Castel Sánchez
mesh_terms: D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007680:Kidney Neoplasms / Q000175:diagnosis / Q000453:epidemiology / Q000628:therapy; D008297:Male; D012189:Retrospective Studies