title: Caution in interpretation of the tumor marker CA 19.9 in patients with obstructive jaundice: illustrative case reports.
abstract: BACKGROUND
  Carbohydrate antigen (CA) 19.9 is a Lewis blood group oligosaccharide antigen which exists in fixed and soluble forms. The CA 19.9 antigen is synthesized by epithelial cells of the gastrointestinal tract, pancreatic duct, and biliary tree. The CA 19.9 antigen is commonly used as a tumor marker for malignancies of the pancreas and biliary tract. High levels (> 300 U/ml) of antigen have strongly suggested malignant processes.
  
  
  METHODS
  Four patients are described with markedly elevated levels of CA 19.9 due to benign calculous disease.
  
  
  RESULTS
  Three of four patients underwent endoscopic stone removal followed by cholecystectomy; the fourth patient spontaneously passed stones and had a subsequent cholecystectomy with benign inflammatory pathology. Removal or passage of the obstructing stones produced normalization of the CA 19.9 in each case even with long-term follow-up up to one year. All pathology specimens were interpreted as benign.
  
  
  CONCLUSIONS
  Marked elevations of CA 19.9 may be found in benign obstructive disease and should be interpreted with caution until biliary obstruction is relieved.
authors.affiliation: Department of Surgery, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS 39216, USA. thelling@umc.edu
authors.forename: Thomas S
authors.initials: TS
authors.lastname: Helling
mesh_terms: D000368:Aged; D001661:Biliary Tract Neoplasms / Q000097:blood / Q000175:diagnosis*; D018395:CA-19-9 Antigen / Q000097:blood*; D002760:Cholangiopancreatography, Endoscopic Retrograde; D017081:Cholecystectomy, Laparoscopic; D002764:Cholecystitis / Q000097:blood / Q000175:diagnosis* / Q000601:surgery; D003937:Diagnosis, Differential; D042882:Gallstones / Q000175:diagnosis* / Q000601:surgery; D006801:Humans; D041781:Jaundice, Obstructive / Q000097:blood / Q000175:diagnosis* / Q000601:surgery; D008297:Male; D008875:Middle Aged; D010190:Pancreatic Neoplasms / Q000097:blood / Q000175:diagnosis*; D011237:Predictive Value of Tests
chemical_list: D018395:CA-19-9 Antigen