Autoimmune pancreatitis associated with pancreatic cyst: how can we manage it?

Background Autoimmune pancreatitis (AIP) with cyst formation (ACF) is often refractory to corticosteroid treatment (CST). Aim To determine the characteristic features for the development of ACF. Methods We studied characteristics in AIP patients (n = 116) whether any factors might be related to ACF. Additionally, an individual database of 24 patients was compiled to investigate factors included CST effectiveness. Result The results of univariate analysis for type 1 AIP patients revealed significant association of ACF with the elevation of pancreatic enzymes, peripancreas vascular involvement (PVI) and varix formation at disease onset (P < 0.05), while multivariate analysis revealed only the absence of varix formation (odds ratio = 0.033, P = 0.0015) as a significant independent predictor of the development of ACF. The comparison of the characteristic features in ACF grouped by the diameter of the cysts revealed that only the effectiveness of the CST was significantly recognized in ACF measuring less than 55 mm in diameter than that with patients in the group with smaller cysts (P < 0.05). Conclusion The varix formation is an independent predictor of the development of ACF. A pooled analysis indicated that the disease process might be irreversible in AIP patients with large cystic lesions exceeding 55 mm in diameter and those patients tended to show a refractory course even if CST were conducted.