title: Biliary obstruction induces extremely elevated serum CA 19-9 levels: case report.
abstract: BACKGROUND
  Assessment of carbohydrate antigen (CA) 19-9 levels is used for diagnosis and follow-up of pancreaticobiliary cancers, and high levels of this biomarker are suggestive of a malignancy. CA 19-9 may also be elevated in patients with conditions other than tumors, such as cholestasis, biliary obstruction, and cholecystitis.
  
  
  METHODS
  A 50-year-old male patient presented with jaundice and elevated CA 19-9 levels (161,902 IU/ml). Repeated biopsies of the common bile duct revealed no malignancies. Radiological findings indicated a mass protruding through the common bile duct. Positron emission tomography demonstrated increased (18)F-fluoro2-deoxy-D-glucose uptake in the liver and a mass resembling metastasis was detected. A Whipple procedure was performed and demonstrated no tumor. Postoperatively, CA 19-9 levels decreased to within normal limits (27 IU/ml).
  
  
  CONCLUSIONS
  These results indicate that CA 19-9 levels should not be the sole criterion for a diagnosis of malignancy. Although other analytical tools may aid diagnosis, surgical exploration may be required in some instances to avoid misdiagnosis and determine whether radiological results are falsely positive.
authors.affiliation: Department of Radiation Oncology, Baskent University Faculty of Medicine, Adana, Turkey. hcemonal@hotmail.com
authors.forename: Cem
authors.initials: C
authors.lastname: Onal
authors.forename: Tamer
authors.initials: T
authors.lastname: Colakoglu
authors.forename: Serife N
authors.initials: SN
authors.lastname: Ulusan
authors.forename: Ali F
authors.initials: AF
authors.lastname: Yapar
authors.forename: Fazilet
authors.initials: F
authors.lastname: Kayaselcuk
mesh_terms: D001661:Biliary Tract Neoplasms / Q000097:blood* / Q000175:diagnosis*; D014408:Biomarkers, Tumor / Q000097:blood*; D018395:CA-19-9 Antigen / Q000097:blood*; D002761:Cholangitis / Q000097:blood* / Q000175:diagnosis* / Q000601:surgery; D003937:Diagnosis, Differential; D005189:False Positive Reactions; D006801:Humans; D008297:Male; D008875:Middle Aged; D016896:Treatment Outcome
chemical_list: D014408:Biomarkers, Tumor; D018395:CA-19-9 Antigen