The Role of Endoscopic Ultrasound-guided Drainage for Autoimmune Pancreatitis-associated Pancreatic Cysts: A Report of Five Cases and a Literature Review

: Objective Autoimmune pancreatitis (AIP) has been recognized as a benign disease, which that shows a prompt response to corticosteroid treatment (CST). It was previously believed to not be associated with cyst formation; however, a few cases of AIP-associated pancreatic cyst (PC) have been reported. Some cases were reported to have been effectively treated by CST, while others were refractory to CST. Many of the patients received interventional treatment. Until now, there has been no consensus on the therapeutic strategies for AIP-associated PC. The aim of the present study is to describe a therapeutic strategy for this condition. Methods We conducted a retrospective study of 5 cases of AIP-associated PC that were treated by endoscopic ultrasonography-guided pancreatic fluid collection drainage (ESPD) or CST at Tokyo Medical University Hospital between March 2012 and October 2016, analyzed the therapeutic outcomes, and performed a literature review. Results The initial treatments included CST (n=2) and ESPD (n=3). All of the PCs disappeared after treatment In 1 of the patients who received CST case and 3 of the patients who received ESPD; however, the PC did not disappear in one of the patients who received CST (corticosteroid maintenance therapy), even after the dose of corticosteroids was increased; ESPD was eventually performed and the PC disappeared. There were no procedure-related complaints. Conclusion We propose that CST be administered as the first-line treatment for AIP-associated PC, particularly in cases of PC without a history of CST. However, ESPD can be applied to treat cases of corticosteroid refractory PC.