Table 2

The International Consensus of Diagnostic Criteria (ICDC) for definite and probable type 1 autoimmune pancreatitis (adapted from Shimosegawa et al [7])

CriterionLevel 1Level 2
P. Parenchymal imagingTypical:
Diffuse enlargement with delayed enhancement (sometimes associated with rim-like enhancement)		Indeterminate (including atypical):
Segmental/focal enlargement with delayed enhancement
D. Ductal imaging (ERP)Long (>1/3 length of the main pancreatic duct) or multiple strictures without marked upstream dilatationSegmental/focal narrowing without marked upstream dilatation (duct size <5 mm)
S. SerologyIgG4>2× upper limit of normal valueIgG4 1–2× upper limit of normal value
OOI. Other organ involvementA or BA or B
A. Histology of extrapancreatic organs
Any three of the following:

  1. Marked lymphoplasmacytic infiltration with fibrosis and without granulocytic infiltration.

  2. Storiform fibrosis.

  3. Obliterative phlebitis.

  4. Abundant (>10 cells/hpf) IgG4 positive cells.

A. Histology of extrapancreatic organs including endoscopic biopsies of bile duct*
Both of the following:

  1. Marked lymphoplasmacytic infiltration without granulocytic infiltration.

  2. Abundant (>10 cells/hpf) IgG4 positive cells.

B. Typical radiological evidence
At least one:

  1. Segmental/multiple proximal (hilar/intrahepatic) or proximal and distal bile duct stricture.

  2. Retroperitoneal fibrosis.

B. Physical or radiological evidence
At least one:

  1. Symmetrically enlarged salivary/lacrimal glands.

  2. Radiologic evidence of renal involvement described in association with AIP.

H. Histology of pancreasLPSP (core biopsy/resection)
At least three of the following:

  1. Periductal lymphoplasmacytic infiltrate without granulocytic infiltration.

  2. Obliterative phlebitis.

  3. Storiform fibrosis.

  4. Abundant (>10 cells/hpf) IgG4 positive cells.

LPSP (core biopsy)
Any two of the following:

  1. Periductal lymphoplasmacytic infiltrate without granulocytic infiltration.

  2. Obliterative phlebitis.

  3. Storiform fibrosis.

  4. Abundant (>10 cells/hpf) IgG4 positive cells.

Rt. Response to steroid†Diagnostic steroid trial
Rapid (≤2 weeks) radiologically demonstrable resolution or marked improvement in pancreatic/extrapancreatic manifestations