Diagnostic and therapeutic considerations in biopsy‐proven type 2 autoimmune pancreatitis: comparative analysis with biopsy‐proven type 1 autoimmune pancreatitis

Abstract

Background Autoimmune 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). Methods A retrospective review of the Queensland Health pathology database of histologically proven AIP was conducted. Parameters compared included demographics, diagnostic criterion and post‐treatment outcomes. Results Twenty‐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. Conclusions Diagnostic challenges do exist and clinicians must suspect 2 type AIP in young, serum IgG4‐negative inflammatory bowel disease patients with recurrent pancreatitis.

Unraveling the relationship between autoimmune pancreatitis type 2 and inflammatory bowel disease: Results from two centers and systematic review of the literature

“…Interestingly, AIP patients with IBD in our cohort were more likely to have a definite diagnosis compared with studies included in the systematic review, 55% versus 38.0% respectively 13,20–22,42 . In line with the observations of the systematic review, the ratio of UC to CD in our study was 3:1 10,11,13,14,18–33,36–47 . Moreover, the location and behavior of the CD according to the Montreal classification 16 were similar to the results reported by Lorenzo et al., 22 with predominantly non‐stricturing, non‐penetrating disease, located mainly in the colon.…”

“…AIP patients with IBD were more likely to have acute pancreatitis (not statistically significant) and abdominal pain at presentation. The prevalence of acute pancreatitis in our cohort was similar to that identified from the systematic review of the literature, 45.2% versus 45.7% 10,21,22,24,25,27–29,48 . Hart et al 24 .…”

“…AIP clinical presentation was mentioned in 12 reports (227 patients). 5 , 10 , 13 , 18 , 19 , 21 , 22 , 24 , 25 , 27 , 28 , 29 Acute pancreatitis was the initial manifestation in 105 patients (46.2%) and jaundice in 19 (8.4%). AIP treatment was reported in 16 studies (316 patients).…”

“…AIP treatment was reported in 16 studies (316 patients). 13 , 14 , 18 , 19 , 20 , 22 , 23 , 24 , 25 , 27 , 28 , 29 , 30 , 31 , 32 , 33 Surgery was performed in 91 patients (28.8%), while systemic steroids were used in 94 patients (29.7%). A watchful waiting strategy was used in 49 patients (15.5%).…”

A Rare Case of Acute Pancreatitis with Concomitant Ulcerative Colitis

“…Type 2 AIP is a rare inflammatory condition that can be difficult to diagnose accurately. 1 UC may co-occur in patients with type 2 AIP. 2 Pathologic findings such as granulocystic and lymphoplasmacytic acinar infiltration without or lacking IgG4-positive cells on EUS-FNB and steroid responsiveness are crucial for diagnosis of type 2 AIP.…”