Autoimmune pancreatitis and inflammatory bowel disease: case series and review of the literature

Background An association between autoimmune pancreatitis (AIP) and inflammatory bowel disease (IBD) has been documented, but its clinical significance remains unclear. Aims Characterize the particular phenotypes of IBD and AIP in patients with both diseases (IBD-AIP). Methods Retrospective study of patients with IBD-AIP followed at our IBD referral centre and literature search to identify previous reports of IBD-AIP patients. Results We found 5 cases of IBD-AIP in our records and 5 prior studies reporting 47 additional IBD-AIP patients. A combined analysis showed that most IBD-AIP patients were young males with ulcerative colitis, usually extensive, and that in all Crohn's disease cases, the colon was involved. IBD severity was heterogeneous across studies, ranging from mild disease to severe disease requiring colectomy. The most frequent type of AIP was idiopathic duct-centric pancreatitis (type 2) and it most often occurred after the diagnosis of IBD. AIP presentation and treatment were similar to those in the general population. Conclusions AIP occurs rarely with IBD; in the other way around, up to 1/3 of AIP patients, especially type 2, may have concomitant IBD. IBD-AIP patients are usually males presenting extensive colitis. More data are needed on the impact of AIP, if any, in IBD course.