Diagnosis

Diagnosis

There is no single test to confirm IgG4-RD and diagnosis depends on the combination of clinical presentation, inflammatory masses on cross sectional imaging, a raised serum IgG4 and characteristic histopathological features which comprise a lymphoplasmacytic infiltrate rich in IgG4+ plasma cells, obliterative phlebitis and storiform fibrosis (Deshpande et al., 2012). Diagnostic criteria to aid decision-making have been agreed on by international consensus for both pancreatic and extra-pancreatic disease (Chari et al., 2006; Okazaki et al., 2017

Diag. Immunostaining of the bile duct showing infiltrating IgG4-positive plasma cells (DAB-positive dark brown).  

Diag. CT abdomen and pelvis with contrast showing a mass at the head of the pancreas in a patient with Autoimmune Pancreatitis Type 1. The mass obstructs the distal common bile duct with proximal intra hepatic duct dilatation and mild pancreatic duct dilatation.

• Clinical presentation
• Serum IgG4 levels
• Imaging studies
• Biopsy evidence
• Response to treatment, including corticosteroids

Clinicians can use one of the following criteria to see if a patient may have a diagnosis of IgG4-RD

1. HISORt Criteria for autoimmune pancreatitis

HISTORt Criteria for the diagnosis of Autoimmune Pancreatitis and adapted for IgG4 related sclerosing cholangitis

2. Japanese CDC for systemic disease

Comprehensive diagnostic criteria for IgG4-related disease (IgG4-RD), 2011

3. Boston Histopathological Criteria

Characteristic histological features: Dense lymphoplasmacyctic inflitrate, fibrosis usually storiform in character, obliterative phlebitis

An IgG4 Responder Index has been developed and validated internationally to monitor disease activity