Autoimmune pancreatitis. Lars Aabakken Oslo University Hospital - Rikshospitalet Oslo, Norway

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1 Autoimmune pancreatitis Lars Aabakken Oslo University Hospital - Rikshospitalet Oslo, Norway

2 Autoimmune pancreatitis Concept introduced in 1961 (Sarles) Re-invented in Japan 1995 (Yoshida) Increasingly recognized also in the West Various definitions and diagnostic criteria proposed, partially due to regional differences Extrapancreatic features offer diagnostic support but also clinical challenges

3 Clinical presentation Painless jaundice Upper abdominal discomfort Acute pancreatitis Endocrine dysfunction (frequent) Exocrine function (rarer) Symptoms of other associated disorders (45%) Sclerosing cholangitis Sjögren, Sialoadenitis Retroperitoneal fibrosis IBD Hilar/mediastinal adenopathy

4 CT Diagnostic imaging Diffuse pancreatic enlargement (sausage shape) or Focal enlargement or Defined mass ERCP Diffuse OR focal duct irregularities and strictures Disappearance of right-angled side brances Variable biliary changes MRCP As ERCP but less accurate EUS Sonographic criteria inaccurate (versus pancreatic cancer) Sampling option (TCB)

5 CT findings

6 CT findings

7 Ultrasound findings

8 ERP findings

9 ERCP findings -IgG4-associated sclerosing cholangitis

10 ASC classification Ohara J Gastro 2007

11 PSC or ASC Kamisawa WJG 2009

12 MRCP ductal findings

13 Histology Type I - lymphoplasmacytic Dense infiltration of plasma cells and lymphocytes Perivenular infiltration of lymphocytes with obliterative phlebitis Periductal fibrosis > 10/hpf IgG4 positive cells Elevated plasma IgG4-levels Frequently extrapancreatic changes Type 2 ductcentric (Western type) Granulocytic epithelial lesions (GELs) Lymphoplasmacytic infiltrates but less fibrosis Less changes in other organs No serum marker

14 Histology

15 Immunohistology

16 EUS thru-cut biopsy

17 Papillary biopsy

18 IgG: 70% sensitivitity Serology IgG4: 90% sensitivity IN JAPAN Europe: 20-50% sensitivity Other autoantibodies (Japan): ANA (76%) Anti-lactoferrin (76%) Anti-CA-II (59%) Anti-RF (29%) Anti-SMA (18%)

19 HISORt diagnostic criteria Category Histology Imaging Serology Other organ involvment Response to therapy Criteria 1) Diagnostic (any one): a) Pancreatic histology showing periductal lymphoplasmacytic infiltrate with obliterative phlebitis b) Lymphoplasmacytic infiltrate with abundant IgG4 positive cells in the pancreas 2) Supportive (any one) a) Lymphoplasmacytic infiltrate with abundant IgG4 positive cells in involved extrapancreatic organ b) Lymphoplasmacytic infiltrate with fibrosis in the pancreas Typical CT/MR: Diffusely enlarged gland with delayed (rim) enhancement ERCP: Diffusely irregular, attenuated PD Atypical Pancreatitis, focal pancreatic mass, focal stricture, atrophy, Elevated calcification serum IgG4 (normal <140mg/dl) Biliary strictures, parotid/lacrimal gland involvement, mediastinal adenopathy, retroperitoneal fibrosis Marked improvement with steroid therapy (2 weeks)

20 Japan Steroid therapy Initially mg/dag Tapering over 2-3 months Long term 2.5-5mg maintenance Mayo clinic 40 mg for 2 weeks Tapering over 8 weeks No maintenance Re-treatment on recurrence Crucial issues: Assessment of therapeutic effect Maintenance tx effect on long term prognosis?

21 Treatment response Kamisawa T GUT 2009

22 Treatment effect assessment? Clinical improvement Cholestasis Pain Endocrine/exocrine function Biochemical improvement Imaging improvement CT ERCP (US)

23 Treatment effect

24 Treatment effect

25 Conclusions Autoimmune pancreatitis increasingly recognized as a distinct entity Distinction towards pancreatic cancer difficult but important, and increasingly possible European presentation Higher rate of seronegatives Weak role of autoantibodies Higher rate of IBD and other extrapancreatic lesions Higher rate of presentation with acute pancreatitis Response to steroids more important diagnostic criterion