title: Imaging of ovarian teratomas in children: a 9-year review.
abstract: OBJECTIVE
  Germ cell tumours are the most common ovarian neoplasms in childhood and, of these, teratomas, whether mature or immature, are the most frequently found. Mature teratoma is a benign tumour, whereas the immature type, although also benign, has a more aggressive course, with a propensity to recurrence. A review of the literature revealed that there are some imaging features that may help to differentiate between these 2 types of teratoma, although no systematic comparison has been made. The objective of this study was to review imaging features of ovarian teratomas in children and to assess differentiating imaging features between the mature and immature types of ovarian teratoma.
  
  
  METHODS
  Retrospective analysis of all patients who presented to our institution during a 9-year period (September 1999 to August 2008) with ovarian teratoma as confirmed on histology.
  
  
  RESULTS
  Forty-one patients with pathologically proven ovarian teratoma were found. The patient ages ranged from 4-18 years at presentation (mean [standard deviation] age, 12.4 +/- 3.4 years; median age, 13 years). Thirty patients (73.2%) were found to have mature ovarian teratoma, and 11 (26.8%) had immature teratoma. A component of endodermal sinus tumour was found in one of the immature teratomas. On ultrasonography, the appearance of the immature teratomas was purely solid in 3 (27.3%), mixed solid and cystic in 6 (54.5%), and predominantly cystic in 2 (18%). The mature ovarian teratomas demonstrated a predominantly cystic appearance in 22 (73.3%) and a mixed solid and cystic appearance in 8 (26.6%); there were no cases with a pure solid appearance. The prevalence of the more cystic appearance of the mature type showed significant statistical difference when compared with its prevalence in the immature type (P = .0008, chi(2) test). Other imaging features, such as size, presence of fat, or calcifications, did not show a significant difference between the 2 types of teratoma.
  
  
  CONCLUSIONS
  The predominance of a cystic component and a pure solid component in ovarian teratoma are significant differentiating factors between the mature type and the more aggressive immature type of teratoma.
authors.affiliation: Department of Diagnostic Imaging, Hospital for Sick Children and University of Toronto, Toronto, Ontario, Canada.
authors.forename: Mohammed O S
authors.initials: MO
authors.lastname: Alotaibi
authors.forename: Oscar M
authors.initials: OM
authors.lastname: Navarro
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D018240:Endodermal Sinus Tumor / Q000000981:diagnostic imaging / Q000473:pathology; D005260:Female; D006801:Humans; D010051:Ovarian Neoplasms / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000473:pathology; D011859:Radiography; D013724:Teratoma / Q000175:diagnosis* / Q000000981:diagnostic imaging; D014463:Ultrasonography