Table 2.
Level 1 and Level 2 Criteria for AIP 1 [1].
| Criterion | Level 1 | Level 2 |
|---|---|---|
| Parenchimal imaging Ductal imaging |
Typical: diffuse enlargement with delayed enhancement (sometimes associated with rim-like enhancement) Long (>1/3 length of the main pancreatic duct) or multiple strictures without marked upstream dilatation |
Indeterminate: segmental/focal enlargement with delayed enhancement (it also includes atypical findings, which include low-density mass, pancreatic ductal dilatation, and distal atrophy) Segmental or focal narrowing without marked upstream dilatation (duct size <5 mm) |
| Serology | IgG4 > 2x upper limit of normal value | IgG4 1–2 x upper limit of normal value |
| Other organ involvement | a or b a. Histology of extrapancreatic organs. Any of three of the following: -marked lynphoplasmacytic infiltration with fibrosis and without granulocytic infiltration -storiform fibrosis -obliterative phlebitis -abundant (>10 cells/HPF) IgG4-positive cells b. Typical radiology evidence At least one of the following: -segmental/multiple proximal or proximal and distal bile duct stricture -retroperitoneal fibrosis |
a or b a. Histology of extrapancreatic organ including endoscopic biopsies of bile duct with both of the following: -marked lymphoplasmacytic infiltration without granulocytic infiltration -abundant (>10 cells/HPF) IgG4 positive cells b. Physical or radiological evidence of at least one of the following: -symmetrically enlarged salivary/lachrymal glands -radiological evidence of renal involvement in association with AIP |
| Histology of the pancreas | At least 3 of the following: -periductal lymphoplasmacitic infiltrate without granulocytic infiltration -obliterative phlebitis -storiform fibrosis -abundant (>10 cells/HPF) IgG4 positive cells |
Any 2 of the following: -periductal lymphoplasmacitic infiltrate without granulocytic infiltration -obliterative phlebitis -storiform fibrosis -abundant (>10 cells/HPF) IgG4 positive cells |
| Response to steroid Rapid (<2 weeks) radiologically demonstrable resolution or marked improvement in pancreatic/extrapancreatic manifestations | ||
HPF: high-power field; IgG4: Immunoglobulin G4.