Tumor-like Chronic Pancreatitis Is Often Autoimmune Pancreatitis.
BACKGROUND
Distinguishing between pancreatic cancer and chronic pancreatitis (CP) is often difficult. Certain (5-6%) CP cases are autoimmune in nature, and these patients respond to corticosteroid treatment, making surgery avoidable. Our aim was to evaluate the incidence of autoimmune pancreatitis (AIP) among patients operated on for a pancreatic mass with a final histology of CP.


METHODS
A total of 33 patients were operated on at the Tampere or Helsinki University Hospital for suspicion of cancer, but with final histopathological diagnosis of CP. The median age was 58 (31-81) years; 26 patients (79%) were male. There were 28 pancreaticoduodenectomes and five left pancreatic resections. Surgical specimens were re-evaluated by experienced pathologists, with representative samples chosen for immunohistochemistry Each sample was scored as positive or negative for immunoglobulin G4 (IgG4) independently by two pathologists. Honolulu consensus criteria served for AIP sub-typing.


RESULTS
Out of the 33 specimens, 10 (30%) were positive for IgG4. Histopathological re-evaluation of these revealed all to be type 1 AIP.


CONCLUSIONS
The proportion of AIP, according to IgG4-positive immunohistochemistry and histological re-evaluation, was much higher than expected. This suggests that by focusing on diagnosis of AIP preoperatively, certain patients might be treated with corticosteroids and possibly avoid unnecessary surgery.
Department of Gastroenterology and Alimentary Tract Surgery, Tampere University Hospital, Tampere, Finland.
Sari
S
Ráty
Department of Gastroenterology and Alimentary Tract Surgery, Tampere University Hospital, Tampere, Finland juhani.sand@pshp.fi.
Juhani
J
Sand
Department of Gastroenterology and Alimentary Tract Surgery, Tampere University Hospital, Tampere, Finland.
Isto
I
Nordback
Department of Clinical Radiology, Tampere University Hospital, Tampere, Finland.
Irina
I
Rinta-Kiikka
Laboratory Center, Tampere University Hospital, Tampere, Finland.
Kaija
K
Vasama
Department of Pathology, Helsinki University Hospital, Helsinki, Finland.
Jaana
J
Hagström
Department of Pathology, Helsinki University Hospital, Helsinki, Finland.
Stig
S
Nordling
Department of Surgery, Helsinki University Hospital, Helsinki, Finland.
Jukka
J
Sirén
Department of Surgery, Helsinki University Hospital, Helsinki, Finland.
Tuula
T
Kiviluoto
Department of Surgery, Helsinki University Hospital, Helsinki, Finland Research Programs Unit, Translational Cancer Biology, University of Helsinki, Helsinki, Finland.
Caj
C
Haglund
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001327:Autoimmune Diseases / Q000097:blood / Q000175:diagnosis* / Q000601:surgery; D015415:Biomarkers / Q000097:blood*; D003937:Diagnosis, Differential; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007124:Immunoenzyme Techniques; D007074:Immunoglobulin G / Q000097:blood*; D008297:Male; D008875:Middle Aged; D010180:Pancreatectomy; D010190:Pancreatic Neoplasms / Q000097:blood / Q000175:diagnosis* / Q000601:surgery; D050500:Pancreatitis, Chronic / Q000097:blood / Q000175:diagnosis* / Q000601:surgery; D011379:Prognosis; D012189:Retrospective Studies
D015415:Biomarkers; D007074:Immunoglobulin G
IgG4; autoimmune pancreatitis; chronic pancreatitis