title: External validation of the paediatric risk of malignancy index.
abstract: OBJECTIVE
  This study aimed to validate the paediatric risk of malignancy index (PRMI), as previously published.
  
  
  METHODS
  External validation study.
  
  
  METHODS
  Academic hospital: Radboud University Medical Center.
  
  
  METHODS
  Female paediatric patients under the age of 18 years diagnosed with, or treated for, an adnexal mass between January 1999 and October 2013.
  
  
  METHODS
  Information was collected on diagnosis, presenting symptoms, and signs and imaging characteristics. The PRMI was calculated for each patient. Sensitivity, specificity, and positive and negative predictive values were calculated, and the results were visualised using a receiver operating characteristic curve (ROC curve).
  
  
  METHODS
  Histological diagnosis, discriminative performance using the area under the curve (AUC) of the ROC curve and sensitivity and specificity.
  
  
  RESULTS
  Seventy-eight patients were included, with a median age of 12 years. A malignant mass was found in 17 patients (21.8%). The PRMI with a cut-off value of 7 resulted in a sensitivity of 70.1% (95% CI 44.1-89.6%) and a specificity of 85.3% (95% CI 73.8-93.0%). The area under the ROC curve was 0.868 (95% CI 0.756-0.980).
  
  
  CONCLUSIONS
  The PRMI showed less discriminative capacity than originally published, but its performance was still good; however, further prospective validation studies are needed to define whether the model is useful in daily clinical practice.
authors.affiliation: Department of Obstetrics & Gynaecology, Radboud University Medical Center, Nijmegen, the Netherlands.
authors.forename: A J
authors.initials: AJ
authors.lastname: Hermans
authors.affiliation: Department of Obstetrics & Gynaecology, Radboud University Medical Center, Nijmegen, the Netherlands.
authors.forename: K B
authors.initials: KB
authors.lastname: Kluivers
authors.affiliation: Department of Obstetrics & Gynaecology, Radboud University Medical Center, Nijmegen, the Netherlands.
authors.forename: L F
authors.initials: LF
authors.lastname: Massuger
authors.affiliation: Department of Obstetrics & Gynaecology, Radboud University Medical Center, Nijmegen, the Netherlands.
authors.forename: S F
authors.initials: SF
authors.lastname: Coppus
mesh_terms: D000290:Adnexa Uteri; D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D005260:Female; D005833:Genital Neoplasms, Female / Q000453:epidemiology*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D012189:Retrospective Studies; D018570:Risk Assessment
keywords: Adolescents; children; external validation; ovarian mass; ovary; risk prediction model