title: Clinical characteristics predicting internal neurofibromas in 357 children with neurofibromatosis-1: results from a cross-selectional study.
abstract: OBJECTIVE
  To identify clinical characteristics associated with internal neurofibromas in children with NF1, as a means of ensuring the early identification of patients at high risk for malignant peripheral nerve-sheath tumors developed from preexisting internal neurofibromas.
  
  
  METHODS
  We used data from two NF1 populations, in France and North America, respectively. The French database comprised 1083 patients meeting NIH diagnostic criteria for NF1 and the Neurofibromatosis Institute Database of North America comprised 703 patients. Patients younger than 17 years of age were eligible for our study if they had been evaluated for internal neurofibromas using computed tomography and/or magnetic resonance imaging. Clinical characteristics associated with internal neurofibromas by univariate analysis (P ≤ 0.15) were entered into a multiple logistic regression model after checking for potential interactions and confounding. Multiple imputation was used for missing values.
  
  
  RESULTS
  Among the 746 children in the two databases, 357 (48%) met our inclusion criteria. Their mean age was 7.7 ± 5.0 years and there were 192 (53.8%) males. Internal neurofibromas were present in 35 (9.8%) patients. Internal neurofibromas developed earlier in females than in males and their prevalence increased during adolescence. Factors independently associated with internal neurofibromas were age (OR = 1.16 [1.07-1.27]), xanthogranulomas (OR = 5.85 [2.18-15.89]) and presence of both subcutaneous and plexiform neurofibromas (OR = 6.80 [1.52-30.44]).
  
  
  CONCLUSIONS
  Several easily recognizable clinical characteristics indicate a high risk of internal neurofibromas in children with NF1 and, therefore, a need for very close monitoring.
authors.affiliation: Université Paris Est (UPEC), LIC EA4393 (Laboratoire d'Investigation Clinique), F-94010, Créteil, France.
authors.forename: Emilie
authors.initials: E
authors.lastname: Sbidian
authors.forename: Smaïl
authors.initials: S
authors.lastname: Hadj-Rabia
authors.forename: Vincent M
authors.initials: VM
authors.lastname: Riccardi
authors.forename: Laurence L
authors.initials: LL
authors.lastname: Valeyrie-Allanore
authors.forename: Sébastien
authors.initials: S
authors.lastname: Barbarot
authors.forename: Olivier
authors.initials: O
authors.lastname: Chosidow
authors.forename: Salah
authors.initials: S
authors.lastname: Ferkal
authors.forename: Diana
authors.initials: D
authors.lastname: Rodriguez
authors.forename: Pierre
authors.initials: P
authors.lastname: Wolkenstein
authors.forename: Sylvie
authors.initials: S
authors.lastname: Bastuji-Garin
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007223:Infant; D008279:Magnetic Resonance Imaging; D008297:Male; D009455:Neurofibroma / Q000000981:diagnostic imaging / Q000473:pathology*; D009456:Neurofibromatosis 1 / Q000473:pathology*; D014057:Tomography, X-Ray Computed