AbstractBackgroundAutoimmune processes are now an increasingly recognized cause of acute and chronic pancreatitis. Autoimmune pancreatitis is a rare, benign pathology with two distinct clinicopathologic subtypes. The aim of this study was to compare the presentation, diagnostic considerations and outcomes of patients with biopsy‐proven type 1 and 2 autoimmune pancreatitis (AIP).MethodsA retrospective review of the Queensland Health pathology database of histologically proven AIP was conducted. Parameters compared included demographics, diagnostic criterion and post‐treatment outcomes.ResultsTwenty‐three patients had a confirmed histological diagnosis of AIP (type 1 = 13, type 2 = 10). Patients with type 2 AIP were younger (median age 49 versus 59 years, P < 0.05). There was no significant difference in gender distribution of disease at presentation. Type 2 AIP presented with significant increased focal pancreatic changes on cross‐sectional imaging (80% versus 54%, P < 0.05). Serum IgG4 levels were raised (>1.40 g/L) in 69% of patients with type 1 AIP and not detected in type 2 (P < 0.01). Concurrent underlying inflammatory bowel disease was present in a higher proportion of type 2 AIP (40% versus 15%, P < 0.05). A significantly increased proportion of patients with type 2 AIP underwent surgical resection (70% versus 30%, P < 0.05). Conservative management was utilized in more patients with type 1 disease (54% versus 30%). On follow‐up, two patients have experienced symptomatic relapse at 6–18 months.ConclusionsDiagnostic challenges do exist and clinicians must suspect 2 type AIP in young, serum IgG4‐negative inflammatory bowel disease patients with recurrent pancreatitis.