Parameters:
(1) histology (H)
(2) imaging (I)
(3) serology (S)
(4) other organ involvement (O)
(5) response to steroid therapy (Rt)
Diagnostic histologic findings – one or both of the following:
(1) lymphoplasmacytic sclerosing pancreatitis (periductal lymphoplasmacytic infiltrate with obliterative phlebitis and storiform fibrosis)
(2) lymphoplasmacytic infiltrate with > 10 IgG4-positive cells per high power field in the pancreas
Supportive histologic findings – one or both of the following:
(1) lymphoplasmacytic infiltrate with fibrosis in pancreas
(2) lymphoplasmacytic infiltrate with > 10 IgG4-positive cells per high power field s in an organ other than the pancreas
Typical findings on imaging – both of the following:
(1) swelling of the pancreas
(2) irregular narrowing of the pancreatic duct
Atypical findings on imaging – one or more of the following:
(1) focal mass
(2) focal pancreatic atrophy
(3) pancreatic calcification
(4) focal stricture of the pancreatic duct
(5) pancreatitis
Serology:
(1) elevated serum concentration of IgG4
Other organ involvement:
(1) biliary duct strictures (hilar and intrahepaic, distal biliary)
(2) parotid or lacrimal gland involvement
(3) mediastinal lymphadenopathy
(4 retroperitoneal fibrosis
Response to steroid therapy:
(1) resolution or marked improvement of pancreatic and extra-pancreatic findings
Diagnosis of AIP can be made by one of the following:
(1) diagnostic histologic findings
(2) typical findings on imaging studies AND positive serology
(3) atypical findings on imaging studies AND positive response to steroid therapy AND (positive serology OR other organ involvement)
