Autoimmune pancreatitis-related cholecystitis: a morphologically and immunologically distinctive form of lymphoplasmacytic sclerosing cholecystitis.
OBJECTIVE
Gallbladder involvement in autoimmune pancreatitis (AIP) is reported to be histologically similar to that seen in primary sclerosing cholangitis (PSC) and biliary obstruction secondary to pancreatic ductal adenocarcinoma (PDAC). The aim was to identify unique morphological and immunological features that could help distinguish gallbladders of AIP from those associated with PSC and PDACs.


RESULTS
Archival gallbladders from well-characterized individuals with AIP (n = 22), PSC (n = 13) and PDAC (n = 23) were examined. Quantitative immunohistochemical analysis for IgG and IgG4 plasma cells was performed and an IgG4/IgG ratio was derived. Dense extramural infiltrates were almost exclusively seen in AIP cases (41%), but seen in only 4% of PDAC-associated cases and 0% of PSC cases (P = 0.001). Phlebitis was more frequently noted in AIP cases (41%) (P = 0.03). Inflammatory nodules were almost exclusively seen in AIP (27%) (P = 0.04). AIP gallbladders showed higher IgG4/IgG ratios (P = 0.0001) than PDAC-associated and PSC gallbladders.


CONCLUSIONS
The findings support our hypothesis that gallbladder involvement in AIP is a primary manifestation of this disease and not a secondary phenomenon related to biliary obstruction. In conjunction with imaging and serology, examination of the gallbladder could provide collaborative evidence of AIP. Evaluation of the gallbladder could also distinguish PSC from AIP-related cholangitis.
Wang
Wei-Lia
WL
The James Homer Wright Pathology Laboratories, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
Farris
Alton B
AB
Lauwers
Gregory Y
GY
Deshpande
Vikram
V
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001327:Autoimmune Diseases / Q000150:complications* / Q000276:immunology / Q000473:pathology; D021441:Carcinoma, Pancreatic Ductal / Q000150:complications / Q000276:immunology / Q000473:pathology; D015209:Cholangitis, Sclerosing / Q000150:complications / Q000276:immunology / Q000473:pathology; D002764:Cholecystitis / Q000209:etiology* / Q000276:immunology / Q000473:pathology; D003937:Diagnosis, Differential; D005260:Female; D005704:Gallbladder / Q000276:immunology / Q000473:pathology; D006801:Humans; D007074:Immunoglobulin G / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D010190:Pancreatic Neoplasms / Q000150:complications / Q000276:immunology / Q000473:pathology; D010195:Pancreatitis / Q000150:complications* / Q000276:immunology / Q000473:pathology; D010950:Plasma Cells / Q000276:immunology / Q000473:pathology; D055815:Young Adult
D007074:Immunoglobulin G