Diagnostic criteria for AIP and IgG4-RD: The Mayo Clinic criteria for the diagnosis of AIP, the HISORt criteria11
| 1. | Histopathology: one or both criteria required | Characteristic appearances within biopsy or resection material* |
| At least 10 IgG4-positive plasma cells per high power field within areas of lymphoplasmacytic infiltrate | ||
| 2. | Imaging & serology: all three criteria required | Diffusely enlarged pancreas with delayed and ‘rim’ enhancement |
| Irregular pancreatic duct | ||
| Increased serum IgG4 concentration | ||
| 3. | Response to steroid therapy: all three criteria required | Unexplained pancreatic disease after a full clinical workup, including exclusion of cancer |
| Raised serum IgG4 concentration and/or extrapancreatic organ involvement with increased numbers of tissue IgG4-positive plasma cells | ||
| Resolution or marked improvement in disease with steroid therapy |
A diagnosis of AIP requires the presence of criteria within at least one of these groups.
↵* This includes a lymphoplasmacytic infiltrate, ‘storiform’ fibrosis and obliterative phlebitis; the inflammatory cell infiltrate alone is not sufficient to meet this criterion.
AIP, autoimmune pancreatitis; IgG4-RD, immunoglobulin G subclass 4-related disease.