IgG4-related disease manifesting as an acute gastric-pericardial fistula.

IgG4-related disease is a recently recognized entity linked initially to autoimmune pancreatitis and has been subsequently described in nearly every organ system. Men over the age of 50 represent the most affected demographic group and a comprehensive set of diagnostic criteria has been developed to aid treating clinicians. Though elevated levels of IgG4 in the serum are suggestive of the disease, definitive diagnosis is made on histopathology. Treatment is tailored to the clinical presentation with corticosteroid therapy known to have proven efficacy. Gastric manifestations of the IgG4-related disease primarily come in two varieties, notably chronic ulceration or pseudotumor formation. Autoimmune pancreatitis conveys increased risk for IgG4-related disease of the stomach, which is independent of Helicobacter pylori status. In this case report, we present an acute gastric-pericardial fistula secondary to IgG4-related disease that required urgent operative management. To our knowledge, this is the first report in the medical literature describing this complication of IgG4-related disease.