title: A case of mature teratoma with a falsely high serum estradiol value measured with an immunoassay.
abstract: BACKGROUND
  Immunoassays (IAs) are widely used to measure concentration of serum estradiol (E2) despite some limitations including cross-reactivity. Liquid chromatography-tandem mass spectrometory (LC-MS/MS) for E2 measurement has a theoretically greater specificity and sensitivity than IAs. We report a case with unexpected discrepancy in E2 values measured by IA and LC-MS/MS.
  
  
  METHODS
  A 7-year-old girl was referred because of an ovarian tumor. Physical examinations revealed prepubertal statuses. Serum E2 with ECLIA was 69 pg/mL. GnRH stimulation test revealed a prepubertal response. On imaging studies, the diagnosis was mature teratoma of the right ovary. After tumor enucleation, the diagnosis was pathologically confirmed. E2 with ECLIA decreased to 11 pg/mL. Preoperative E2 with LC-MS/MS was 1.15 pg/mL.
  
  
  CONCLUSIONS
  We conclude the preoperative E2 with ECLIA was falsely high. We speculate the antibody used in ECLIA had cross-reactivity to endogenous compounds. LC-MS/MS should be considered when high serum E2 measured with IA is inconsistent with physical and/or endocrinological data.
authors.forename: Mayumi
authors.initials: M
authors.lastname: Hosokawa
authors.forename: Hironori
authors.initials: H
authors.lastname: Shibata
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Ishii
authors.forename: Akihiro
authors.initials: A
authors.lastname: Fujino
authors.forename: Tatsuo
authors.initials: T
authors.lastname: Kuroda
authors.forename: Kenjiro
authors.initials: K
authors.lastname: Kosaki
authors.forename: Kaori
authors.initials: K
authors.lastname: Kameyama
authors.forename: Tomonobu
authors.initials: T
authors.lastname: Hasegawa
mesh_terms: D002648:Child; D002853:Chromatography, Liquid; D004958:Estradiol / Q000097:blood*; D005260:Female; D006801:Humans; D007118:Immunoassay; D008163:Luminescent Measurements; D053719:Tandem Mass Spectrometry; D013724:Teratoma / Q000097:blood*
chemical_list: D004958:Estradiol