title: Maturation of mass-screened localized adrenal neuroblastoma.
abstract: OBJECTIVE
  In infants, neuroblastoma has been known to spontaneously differentiate into a benign ganglioneuroma. Although several investigators have compared mass-screened with unscreened, disseminated with localized, and adrenal with retroperitoneal neuroblastoma, there are very few cross-comparisons of the above parameters. Herein, the authors report the maturation of mass-screened, localized adrenal neuroblastoma.
  
  
  METHODS
  Fifty-one mass-screened adrenal neuroblastomas were divided into 2 groups. In infants less than 1 year of age (Group A), 45 neuroblastomas were resected, whereas 6 neuroblastomas were resected after observation in 1- to 4-year-old children (group B). Histopathology of the tumors in the 2 groups was compared. Data were analyzed by X(2) test, and P <.05 was considered significant.
  
  
  RESULTS
  According to the International Neuroblastoma Pathological Classification, 41 of 45 tumors of group A were "differentiating neuroblastoma" and 4 of 6 tumors of group B were "maturing ganglioneuroma." Maturation toward ganglioneuroblastoma was observed in 16 neuroblastomas of group A (36%) and 6 neuroblastomas of group B (100%). In group A, 58% had low mitosis karyorrhexis index (MKI); all patients in group B had low MKI.
  
  
  CONCLUSIONS
  If left untreated, maturation of mass-screened, localized adrenal neuroblastomas is a common phenomenon. These children do not need to undergo early operation.
authors.affiliation: Department of Surgery, Saitama Children's Medical Center, 2100 Magome, Iwatsuki, Saitama 339-8551, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Iwanaka
authors.forename: K
authors.initials: K
authors.lastname: Yamamoto
authors.forename: Y
authors.initials: Y
authors.lastname: Ogawa
authors.forename: M
authors.initials: M
authors.lastname: Arai
authors.forename: M
authors.initials: M
authors.lastname: Ito
authors.forename: H
authors.initials: H
authors.lastname: Kishimoto
authors.forename: R
authors.initials: R
authors.lastname: Hanada
authors.forename: S
authors.initials: S
authors.lastname: Imaizumi
mesh_terms: D000310:Adrenal Gland Neoplasms / Q000145:classification / Q000473:pathology*; D002648:Child; D002675:Child, Preschool; D005729:Ganglioneuroma / Q000145:classification / Q000473:pathology*; D006801:Humans; D007223:Infant; D008403:Mass Screening; D009365:Neoplasm Regression, Spontaneous; D009367:Neoplasm Staging; D009447:Neuroblastoma / Q000145:classification / Q000473:pathology*