Table 7.
Clinical diagnostic criteria for autoimmune pancreatitis in 2011 by Japan Pancreas Society (JPS-2011) (from [64, 65], with permission)
| A. Diagnostic criterion |
|---|
| I. Enlargement of the pancreas: |
| a. Diffuse enlargement |
| b. Segmental/focal enlargement |
| II. ERP (endoscopic retrograde pancreatography) shows irregular narrowing of the main pancreatic duct |
| III. Serological findings |
| Elevated levels of serum IgG4 (≥135 mg/dl) |
| IV. Pathological findings: among i)–iv) listed below, |
| a. Three or more are observed |
| b. Two are observed |
| i) Prominent infiltration and fibrosis of lymphocytes and plasmacytes |
| ii) Ten or more diffuse IgG4-positive plasmacytes per high-power microscope field |
| iii) Storiform fibrosis |
| iv) Obliterative phlebitis |
| V. Other organ involvement (OOI): sclerosing cholangitis, sclerosing dacryoadenitis/sialoadenitis, retroperitoneal fibrosis |
| a. Clinical lesions |
| Extra-pancreatic sclerosing cholangitis, sclerosing dacryoadenitis/sialoadenitis (Mikulicz disease), or retroperitoneal fibrosis can be diagnosed with clinical and image findings. |
| b. Pathological lesions |
| Pathological examination shows characteristic features of sclerosing cholangitis, sclerosing dacryoadenitis/sialoadenitis, or retroperitoneal fibrosis. |
| <Option> Effectiveness of steroid therapy |
| A specialized facility may include in its diagnosis the effectiveness of steroid therapy, once pancreatic or bile duct cancers have been ruled out. When it is difficult to differentiate from malignant conditions, it is desirable to perform cytological examination using an endoscopic ultrasound-guided fine needle aspiration (EUS-FNA). Facile therapeutic diagnosis by steroids should be avoided unless the possibility of malignant tumor has been ruled out by pathological diagnosis. |
| B. Diagnosis |
|---|
| I. Definite diagnosis |
| 1 Diffuse type |
| I a + < III/IVb/V(a/b)> |
| 2 Segmental/focal type |
| I b + II + two or more of <III/IV b/V (a/b)> |
| I b + II + < III/IV b/V (a/b)> + Option |
| 3 Definite diagnosis by histopathological study |
| IV a |
| II. Probable diagnosis |
| Segmental/focal type: I b + II + < III/IV b/V (a/b)> |
| III. Possible diagnosisa |
| Diffuse type: I a + II + Option |
| Segmental/focal type: I b + II + Option |
When a patient with a focal/segmental image of AIP on CT/MRI without ERCP findings fulfill more than one of III, IVb and V(a/b) criteria, he/she can be diagnosed as possible AIP only after the negative workup for malignancy by EUS-FNA, and confirmed as probable one by an optional steroid response
aPossible diagnosis: a case may be possibly type 2, although it is extremely rare in Japan
“+” refers to “and”, and “/” refers to “or”