Autoimmune pancreatitis (AIP), in particular type 1, is the pancreatic manifestation of immunoglobulin G4 (IgG4)-associated systemic fibrosing disease.1–5 AIP should be especially considered in elderly men presenting with jaundice, abdominal pain and weight loss. Imaging studies reveal a diffusely enlarged pancreas with widespread irregular narrowing of the pancreatic duct without upstream dilation, as often seen in pancreatic cancer. Not uncommonly, there is associated stricture of the common bile duct. These findings in men above 55 years of age are usually suggestive of pancreatic cancer, which is indeed 10-fold more common than AIP, but malignant cells are absent in the lesion. Instead, there is diffuse infiltration of IgG4-plasma cells together with T cells. This may be associated with raised plasma IgG4 levels, often more than twice the upper limit of normal, seen in 50–80% of AIP patients. IgG4 antibodies have low affinity for C1q and Fc-receptors, explaining their mitigated anti-inflammatory activity.