title: Magnetic resonance manifestations of hyperreactio luteinalis.
abstract: OBJECTIVE
  Hyperreactio luteinalis (HL) is a rare benign physiological ovarian enlargement associated with gestational trophoblastic disease or pregnancy, and may mimic neoplasm. We evaluated magnetic resonance findings of HL to distinguish from neoplasm by using diffusion-weighted imaging with apparent diffusion coefficient (ADC) measurement.
  
  
  METHODS
  Magnetic resonance manifestations of 15 cases of HL in 8 women (mean age, 32 years) were retrospectively evaluated. Diffusion-weighted imaging (b = 0 and 800 seconds/mm²) was obtained in 11 cases of HL, and ADC was compared with that in solid portions of 18 ovarian cancers.
  
  
  RESULTS
  All cases of HL appeared as multilocular cystic masses with septations mimicking mucinous cystic tumors. Intervening ovarian stroma exhibited hyperintensity on diffusion-weighted imaging. The ADC in ovarian stroma in HL was significantly higher than that in solid portions of ovarian cancers.
  
  
  CONCLUSIONS
  Ovarian stroma in HL may mimic solid tumorous components in mucinous tumors; however, high ADC reflecting edematous, luteinized stroma may be helpful for the diagnosis of HL.
authors.affiliation: Department of Radiology, University of Tokushima, Tokushima, Japan. mayumi@clin.med.tokushima-u.ac.jp
authors.forename: Mayumi
authors.initials: M
authors.lastname: Takeuchi
authors.forename: Kenji
authors.initials: K
authors.lastname: Matsuzaki
mesh_terms: D000328:Adult; D003287:Contrast Media; D003937:Diagnosis, Differential; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D010048:Ovarian Cysts / Q000175:diagnosis* / Q000473:pathology; D010051:Ovarian Neoplasms / Q000175:diagnosis / Q000473:pathology; D010053:Ovary / Q000473:pathology; D011247:Pregnancy; D011248:Pregnancy Complications / Q000175:diagnosis* / Q000473:pathology; D012189:Retrospective Studies; D018709:Statistics, Nonparametric
chemical_list: D003287:Contrast Media