Objectives: Autoimmune pancreatitis (AIP) sometimes becomes complicated with pancreatic cysts, although their detailed characteristics and management strategy have not been fully determined. We aimed to clarify the efficiency of steroid therapy and the risk factors for cyst formation and cyst-related complications. Methods: One hundred sixty-three AIP patients were retrospectively analyzed for relevant factors of cyst formation. We compared subjects with and without steroids to evaluate drug effectiveness on cyst size change and investigated the factors associated with cyst-related complications. Results: Thirty-two patients (19.6%) had complicating pancreatic cyst formation, and 40 cystic lesions of ≥10 mm in size were detected. Multivariate analysis revealed a drinking habit, abdominal/back pain, and elevated serum amylase to be significantly associated with cyst formation. Steroid-treated cysts became significantly reduced in size in the short-term and disappeared significantly more frequently within 1-year as compared with non-treated ones, which was confirmed by multivariate analysis. Six of 40 cysts exhibited cyst-related complications significantly associated with multilocular morphology and larger size. Conclusions: Steroid therapy is an effective choice for cysts developing in AIP to promote the release of pancreatic juice stasis. Larger lesions with multilocular morphology should be monitored closely for cyst-related complications and be considered strong candidates for steroid therapy.
Keywords: Autoimmune pancreatitis; cyst; cyst-related complications; pancreatic juice stasis; steroid therapy.