Pancreatic Pseudocysts and Parenchymal Necrosis in Patients With Autoimmune Pancreatitis: A Systematic Review

Abstract

Introduction: Autoimmune Pancreatitis (AIP) is being increasingly recognized as a cause of acute pancreatitis (AP). The resulting potential complications of AP such as pancreatic pseudocysts (PC) and parenchymal necrosis and their natural history and management are unknown in patients with AIP. The aim of this systematic review was to examine the prevalence of the AP complications of PC and pancreatic necrosis in patients with AIP as well as their characteristics, management and outcomes. Methods: A systematic search using PubMed/Medline, Embase, Scopus, and Cochrane was performed without language or year limitations to October 1, 2016 with a medical reference librarian. Search terms were “Autoimmune pancreatitis”, “pancreatic pseudocyst”, “acute fluid collection” and “pancreatic necrosis” with all permutations. AIP was defined according to international guidelines. The search yielded 271 results. 17 case reports dating from 2004 to 2015 were included in this systematic review. Results: 12/17 (70.6%) patients were men, with a mean age of 54.82 ± 10.97 years (Range 26-75 years). In 8/17 cases, the PC were noted concurrently with the AIP diagnosis, while in the other half, the PC appeared several months or even years after the initial AIP diagnosis. In 10/17 cases, the PC appeared on imaging as solitary, while in the remaining 7 there were multiple PC. The location of the PC was variable, being present in any segment of the pancreas. PC ranged in size from small (3cm) in 13 cases. 9cm was the maximal diameter reported. 6/17 (35%) cases had a normal pancreatic duct on imaging, while 9/17 (53%) had a narrowed/stenotic pancreatic duct. 14/17 cases received steroid therapy (4/4 small, and 10/13 large PC). All 4 small PC responded completely to steroid therapy, while only 4 of 10 (40%) with large PC treated with steroids had response. 9 of the 13 cases of large PC eventually went on to undergo endoscopic or surgical interventions. None of the 17 cases had pancreatic necrosis. Conclusion: The development of PC in AIP is a rare phenomenon with only 17 cases reported. PC can be single or multiple with variable size and location. Small PC all responded to steroid therapy. Conversely, large PC had poor response to steroid therapy, and required endoscopic or surgical drainage. AIP has not been reported to be associated with development of pancreatic necrosis.