title: Adnexal masses in children, adolescents and women of reproductive age in the Netherlands: A nationwide population-based cohort study.
abstract: To provide an accurate incidence of adnexal masses in children and young women which can significantly improve the performance of current risk prediction models.
  
  
  
  We used the PALGA database, a nationwide network and registry of histopathology and cytopathology, as the primary source of our study. Reports on ovarian histology of girls, years 1991-2014, and women aged 21-39, years 2011-2013, were included. Reports were labeled using the WHO-classification and classified as benign, borderline malignant, or malignant. Surgical procedure was scored separately.
  
  
  
  Included were 11,595 patients. The incidence of adnexal masses increased exponentially with age, from 0.43 per 100,000womenyears at age 1 to 152 per 100,000womenyears at age 35. A (borderline) malignancy was found in 898 (7.7%) patients, ratios between benign and malignant masses varied with age and were lowest in premenarchal children. Histology varied widely with surface epithelial tumors (35.1%), germ cell tumors (29.8%), and other cysts, tumors and tumorlike lesions (32.8%) being evenly distributed while sex cord stromal tumors were rare and only represented 2.3%. The proportion of malignancies was 6.3% in germ cell tumors while the type of malignant germ cell tumor was dependent on age. Oophorectomy was more often performed in the premenarchal age group and in women approaching the end of their reproductive age.
  
  
  
  Our results show that adnexal masses in different age groups do not only differ in histological subgroups but also in malignancy rate which is of high value in presurgical risk evaluation.
authors.affiliation: Department of Obstetrics & Gynaecology, Radboud University Medical Center, PO Box 9101, 6500 HB, Nijmegen, The Netherlands. Electronic address: ayke.hermans@radboudumc.nl.
authors.forename: Ayke J
authors.initials: AJ
authors.lastname: Hermans
authors.affiliation: Department of Obstetrics & Gynaecology, Radboud University Medical Center, PO Box 9101, 6500 HB, Nijmegen, The Netherlands.
authors.forename: Kirsten B
authors.initials: KB
authors.lastname: Kluivers
authors.affiliation: Department of Obstetrics & Gynaecology, Radboud University Medical Center, PO Box 9101, 6500 HB, Nijmegen, The Netherlands.
authors.forename: Laura M
authors.initials: LM
authors.lastname: Janssen
authors.affiliation: Department of Pathology, Radboud University Medical Center, PO Box 9101, 6500 HB, Nijmegen, The Netherlands.
authors.forename: Albert G
authors.initials: AG
authors.lastname: Siebers
authors.affiliation: Department of Pediatric Surgery, Princess Máxima Centre for Paediatric Oncology, PO Box 85090, 3508 AB Utrecht, The Netherlands.
authors.forename: Marc H W A
authors.initials: MHWA
authors.lastname: Wijnen
authors.affiliation: Department of Pathology, Radboud University Medical Center, PO Box 9101, 6500 HB, Nijmegen, The Netherlands.
authors.forename: Johan
authors.initials: J
authors.lastname: Bulten
authors.affiliation: Department of Obstetrics & Gynaecology, Radboud University Medical Center, PO Box 9101, 6500 HB, Nijmegen, The Netherlands.
authors.forename: Leon F A G
authors.initials: LFAG
authors.lastname: Massuger
authors.affiliation: Department of Obstetrics & Gynaecology, Radboud University Medical Center, PO Box 9101, 6500 HB, Nijmegen, The Netherlands.
authors.forename: Sjors F P J
authors.initials: SFPJ
authors.lastname: Coppus
mesh_terms: D000291:Adnexal Diseases / Q000453:epidemiology* / Q000473:pathology / Q000601:surgery; D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D005260:Female; D006801:Humans; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D009373:Neoplasms, Germ Cell and Embryonal; D009426:Netherlands / Q000453:epidemiology
keywords: Adnexal mass; Children; Epidemiology; Histology; Incidence; Reproductive age