title: Pathological Features of the Unilateral Favorable Histology Nephroblastoma with Relapse.
abstract: OBJECTIVE
  To evaluate the pathological features of the primary lesion in patients with relapse of unilateral favorable histology nephroblastoma.
  
  
  METHODS
  Fifty-eight patients with unilateral favorable histology nephroblastoma who underwent initial nephrectomy before chemotherapy were categorized into one of two groups: the nonrelapsed group (n = 52) and the relapsed group (n = 6). The histological subtypes of both groups and pathological features of the relapsed group were re-evaluated retrospectively.
  
  
  RESULTS
  The histological subtypes of all relapsed cases were classified as blastemal predominant. In three of six cases with relapse, sheets of spindle-shaped blastemal cells that were histologically reminiscent of synovial sarcoma were predominant (massive sarcomatoid pattern).
  
  
  CONCLUSIONS
  The histological blastemal predominant subtype of nephroblastoma is a strong indicator of relapse. In particular, the blastemal predominant subtype with massive sarcomatoid pattern may have a higher risk of relapse.
authors.affiliation: a Department of Pediatric Surgery , Kobe Children's Hospital , Kobe , Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Fukuzawa
authors.affiliation: b Division of Pediatric Surgery , St. Marianna University School of Medicine , Kawasaki , Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Aoba
authors.affiliation: c Department of Pathology , Kobe Children's Hospital , Kobe , Japan.
authors.forename: Makiko
authors.initials: M
authors.lastname: Yoshida
authors.affiliation: d Department of Pathology , Shizuoka Children's Hospital , Shizuoka , Japan.
authors.forename: Hideto
authors.initials: H
authors.lastname: Iwafuchi
authors.affiliation: e Department of Diagnostic Pathology , St. Marianna University School of Medicine , Kawasaki , Japan.
authors.forename: Junki
authors.initials: J
authors.lastname: Koike
authors.affiliation: b Division of Pediatric Surgery , St. Marianna University School of Medicine , Kawasaki , Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Kitagawa
authors.affiliation: f Department of Pediatric Surgery , Shizuoka Children's Hospital , Shizuoka , Japan.
authors.forename: Naoto
authors.initials: N
authors.lastname: Urushihara
authors.affiliation: a Department of Pediatric Surgery , Kobe Children's Hospital , Kobe , Japan.
authors.forename: Akiko
authors.initials: A
authors.lastname: Yokoi
authors.affiliation: a Department of Pediatric Surgery , Kobe Children's Hospital , Kobe , Japan.
authors.forename: Kosaku
authors.initials: K
authors.lastname: Maeda
mesh_terms: D002648:Child; D002675:Child, Preschool; D005260:Female; D007839:Functional Laterality; D006801:Humans; D007680:Kidney Neoplasms / Q000473:pathology*; D008297:Male; D009364:Neoplasm Recurrence, Local / Q000473:pathology*; D012189:Retrospective Studies; D009396:Wilms Tumor / Q000473:pathology*
keywords: blastemal predominant; nephroblastoma; relapse