A Nondilated Main Pancreatic Duct Predicts Type 2 Autoimmune Pancreatitis: Comparative Study of Resected Pancreatic Head Masses.

BACKGROUND

Chronic pancreatitis (CP), pancreatic cancer (PCa), and autoimmune pancreatitis (AIP) often present as a pancreatic mass. Accurate diagnosis is not always possible; up to 8% of surgical procedures are performed in benign pancreatic masses presumed to be malignant.

OBJECTIVES

We aimed to compare clinical and imaging characteristics of resected focal type 2 AIP, CP, and PCa and identify factors that could improve preoperative differential diagnosis.

METHODS

Charts from patients that underwent pancreatic resection under suspicion of PCa between 2000 and 2014 were reviewed. Clinical and imaging data were recorded. Subjects were grouped as type 2 AIP, CP, and PCa.

RESULTS

We included 79 cases; 41 men, mean age of 57.3 years/old ± 15.6 SD. Pathology report was type 2 AIP (20%), CP (10%), and PCa (70%). According to international consensus criteria for AIP 11 cases were deemed probable type 2 and 5 as unspecific pancreatic mass. A nondilated main pancreatic duct (MPD) was associated with AIP (OR 9.3; 95% CI 3.05-28.7), p < 0.001; obstructive jaundice (OR 28.5; 95% CI 8.18-79.5); and a dilated MPD (OR 5.21; 95% CI 1.9-14.6) suggested malignancy.

CONCLUSIONS

In the setting of undetermined pancreatic focal mass, a nondilated MPD suggests the diagnosis of type 2 AIP.