Abdomen, Biliary Tract / Gallbladder, Pancreas, CT, MR, PET-CT, Diagnostic procedure, Inflammation
R. Jyani, S. K. Puri, A. K. Chaturvedi, J. Khoda, M. KM
IgG4-related disease is a systemic disease that can affect virtually any organ system in the body, most commonly the pancreas and biliary system. It usually affects patients older than 50 years of age and has a definite male preponderance with a male: female ratio of 2.9 to 3.7 .
Although histo-pathology as well as immuno-histochemistry (IHC) and raised serum IgG4 levels are required for the definite diagnosis, imaging plays an important role to raise the diagnostic possibility and map the entire extent of the disease.
Radiological work-up of these patients should include whole body examinations to rule out multisystem involvement. The diagnosis of IgG4 related diseases is often first suggested on imaging.
Diagnosis is established by the following three criteria: 1) Clinical (history, physical examination and imaging). 2) Hematologic examination (serum IgG4 levels >135 mg/dL). 3) Histopathology (hallmark features include lymphoplasmacytic infiltration, storiform fibrosis, obliterative phlebitis and organ infiltration by IgG4 positive plasma cells on IHC) .
Autoimmune pancreatitis (type I) is the commonest manifestation of IgG4 related diseases but recently, the frequency of reported cases with only extra-pancreatic involvement is on the rise and hence, involvement of the pancreas is not imperative to make the diagnosis