Irregular narrowing of the main pancreatic duct in association with a wall thickening is a key sign at endoscopic ultrasonography for the diagnosis of autoimmune pancreatitis.
OBJECTIVE
The aim of this study was to assess the accuracy of key signs identified at endoscopic ultrasonography in diagnosing an autoimmune pancreatitis (AIP).


METHODS
Between January 2007 and December 2011, a retrospective case-control study was conducted in 177 patients with AIP (n = 30), pancreatic adenocarcinoma (n = 42), pancreatic neuroendocrine tumor (n = 21), alcoholic chronic pancreatitis (n = 32), and symptomatic common bile duct stones (n = 52).


RESULTS
An irregular narrowing of the main pancreatic duct in association with a wall thickening was seen in 28 of 30 AIP, 1 of 42 pancreatic adenocarcinoma, 0 of 21 pancreatic neuroendocrine tumor, 0 of 32 alcoholic chronic pancreatitis, and 0 of 52 common bile duct stones (P < 0.05). Sensitivity, specificity, positive and negative predictive values, and overall diagnostic accuracy of this sign for the diagnosis of AIP were 93%, 99.3%, 96.3%, 98.6%, and 98.3%, respectively. In type 1 AIP, hyperechoic parietal thickening was more frequent (92.3% vs 33.3%, P < 0.05). In type 2 AIP, hypoechoic parietal thickening was more frequent (83.3% vs 23.1%, P < 0.05).


CONCLUSIONS
An irregular narrowing of the main pancreatic duct in association with a wall thickening seen at endoscopic ultrasonography is accurate in diagnosing AIP. The type of echogenicity of the thickening is well correlated with the type of AIP.
From the *Department of Gastroenterology-Pancreatology, Beaujon Hospital, Paris VII Denis Diderot University, Clichy; †Department of Endoscopy, Trocadero Clinic, Paris; ‡Department of Pathology, Gustave Roussy Institute, Villejuif; §Department of Pathology, Bichat Hospital, and ¶Department of Radiology, Beaujon Hospital, Paris VII Denis Diderot University, Clichy, France.
Maxime
M
Palazzo
Laurent
L
Palazzo
Alain
A
Aubert
Monique
M
Fabre
Anne
A
Couvelard
Marie-Pierre
MP
Vullierme
Frédérique
F
Maire
Philippe
P
Lévy
Philippe
P
Ruszniewski
D000293:Adolescent; D000328:Adult; D000368:Aged; D001327:Autoimmune Diseases / Q000000981:diagnostic imaging*; D003251:Constriction, Pathologic; D003937:Diagnosis, Differential; D019160:Endosonography; D005260:Female; D005602:France; D006801:Humans; D008297:Male; D008875:Middle Aged; D010183:Pancreatic Ducts / Q000000981:diagnostic imaging*; D010195:Pancreatitis / Q000000981:diagnostic imaging*; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D055815:Young Adult