title: Pitfalls in avoiding operation for autoimmune pancreatitis.
abstract: BACKGROUND
  Despite improved clinical characterization, autoimmune pancreatitis is often still diagnosed only after a major operative procedure. This study seeks to elucidate the circumstances that contribute to an inaccurate preoperative diagnosis.
  
  
  METHODS
  Two independent reviewers identified retrospectively an institutional cohort of 68 patients with adequate clinical data to support the diagnosis of autoimmune pancreatitis. Further data regarding presentation, diagnostic studies, and clinical course was abstracted from medical records. Comparative analyses were performed between those patients who underwent major operative procedures and those who did not.
  
  
  RESULTS
  Fifty-three patients underwent operative intervention as their initial treatment. Compared to the 15 patients avoiding operation, these patients were less likely to have diffuse pancreatic enlargement identified on pretreatment imaging (8% vs 80%) or to have pretreatment serum IgG4 level evaluations (11% vs 100%). Among the 21 patients in whom IgG4 levels were first checked postoperatively, only 12 had increases of at least twice the upper limit of normal. Pretreatment fine needle aspirates were interpreted incorrectly as definite or suspicious for adenocarcinoma in 12 patients, of whom 10 underwent operation. Clinically important postoperative disease recurrence was suspected or proven in 13 patients.
  
  
  CONCLUSIONS
  Pitfalls leading to major pancreatic resections in autoimmune pancreatitis include unnecessarily high thresholds for initiating serum IgG4 evaluation, false positive cytologic evaluations for malignancy, and failure to recognize non-classic initial presentations, or recurrence of disease. Better diagnostic strategies are needed, but awareness of these specific findings should help to decrease the number of patients undergoing operation for unrecognized autoimmune pancreatitis.
authors: Department of Surgery, San Antonio Military Medical Center, Ft Sam Houston, TX 78234, USA. peter.learn@gmail.com
authors: Peter A
authors: PA
authors: Learn
authors: Evan B
authors: EB
authors: Grossman
authors: Richard K G
authors: RK
authors: Do
authors: Peter J
authors: PJ
authors: Allen
authors: Murray F
authors: MF
authors: Brennan
authors: Michael I
authors: MI
authors: D'Angelica
authors: Ronald P
authors: RP
authors: DeMatteo
authors: Yuman
authors: Y
authors: Fong
authors: David S
authors: DS
authors: Klimstra
authors: Mark A
authors: MA
authors: Schattner
authors: William R
authors: WR
authors: Jarnagin
mesh_terms: D000230:Adenocarcinoma / Q000175:diagnosis; D000368:Aged; D001327:Autoimmune Diseases / Q000175:diagnosis* / Q000601:surgery*; D044963:Biopsy, Fine-Needle; D003937:Diagnosis, Differential; D003951:Diagnostic Errors / Q000517:prevention & control*; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D008297:Male; D008875:Middle Aged; D010190:Pancreatic Neoplasms / Q000175:diagnosis; D010195:Pancreatitis / Q000175:diagnosis* / Q000601:surgery*; D011300:Preoperative Care / Q000592:standards*; D012189:Retrospective Studies; D019564:Unnecessary Procedures
chemical_list: D007074:Immunoglobulin G