title: Discrepant serum and urine β-hCG results due to production of β-hCG by a cribriform-morular variant of thyroid papillary carcinoma.
abstract: BACKGROUND
  Although patients with medullary thyroid cancer are known to present with paraneoplastic hormone production, this is much less common with papillary thyroid cancer.
  
  
  METHODS
  We present a patient with the cribriform morular variant of papillary thyroid cancer in association with familial adenomatous polyposis who developed a positive pregnancy test in the absence of known pregnancy. The patient had developed vaginal bleeding, and her laboratory testing was characterized by elevated serum human chorionic gonadotropin (β-hCG) concentrations, but negative qualitative urine results. After a thorough gynecological evaluation to exclude unexpected normal, ectopic, or molar pregnancy, we pursued an evaluation for other sources of β-hCG production.
  
  
  RESULTS
  We showed that the elevated serum β-hCG concentrations were not the result of heterophile antibody interferences, and ultimately we proved that her recurrent tumor produced the ectopic β-hCG. This is the first report of β-hCG production by papillary thyroid cancer. Thus, the possibility of ectopic production of β-hCG by papillary thyroid cancer needs to be included in the differential diagnosis of elevated hCG concentration in the absence of pregnancy.
  
  
  CONCLUSIONS
  This study of an unusual paraneoplastic syndrome highlights the importance of investigating discrepancies in the clinical laboratory.
authors.affiliation: Department of Pathology, Biological Sciences Division, The University of Chicago, 5841 S. Maryland Avenue, Chicago, IL 60637, United States.
authors.forename: Mir
authors.initials: M
authors.lastname: Alikhan
authors.affiliation: Section of Endocrinology, Department of Medicine, Biological Sciences Division, The University of Chicago, 5841 S. Maryland Avenue, Chicago, IL 60637, United States.
authors.forename: Anoopa
authors.initials: A
authors.lastname: Koshy
authors.affiliation: Department of Pathology, Biological Sciences Division, The University of Chicago, 5841 S. Maryland Avenue, Chicago, IL 60637, United States.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Hyjek
authors.affiliation: Department of Surgery, Biological Sciences Division, The University of Chicago, 5841 S. Maryland Avenue, Chicago, IL 60637, United States.
authors.forename: Kerstin
authors.initials: K
authors.lastname: Stenson
authors.affiliation: Section of Endocrinology, Department of Medicine, Biological Sciences Division, The University of Chicago, 5841 S. Maryland Avenue, Chicago, IL 60637, United States.
authors.forename: Ronald N
authors.initials: RN
authors.lastname: Cohen
authors.affiliation: Department of Pathology, Biological Sciences Division, The University of Chicago, 5841 S. Maryland Avenue, Chicago, IL 60637, United States. Electronic address: jyeo@bsd.uchicago.edu.
authors.forename: Kiang-Teck J
authors.initials: KT
authors.lastname: Yeo
mesh_terms: D011125:Adenomatous Polyposis Coli / Q000097:blood / Q000150:complications / Q000175:diagnosis* / Q000652:urine; D000328:Adult; D015415:Biomarkers / Q000032:analysis*; D002291:Carcinoma, Papillary / Q000097:blood / Q000150:complications / Q000175:diagnosis* / Q000652:urine; D006063:Chorionic Gonadotropin / Q000097:blood* / Q000652:urine*; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D009364:Neoplasm Recurrence, Local / Q000097:blood / Q000150:complications / Q000175:diagnosis* / Q000652:urine; D011247:Pregnancy; D011379:Prognosis; D013964:Thyroid Neoplasms / Q000097:blood / Q000150:complications / Q000175:diagnosis* / Q000652:urine
chemical_list: D015415:Biomarkers; D006063:Chorionic Gonadotropin
keywords: Human chorionic gonadotrophin; Thyroid papillary cancer; hCG immunoassays