Long-Term Follow-Up of Autoimmune Pancreatitis Immunoglobulin G4-Related Disease Diagnosed by EUS-FNA: Case Report

Autoimmune pancreatitis (AIP) is a recurrent, infiltrative, inflammatory disease, which is not limited to pancreatic involvement and has a multiform clinical presentation.Morphological changes lead to irreversible destruction of the exocrine and endocrine glands with consequent pancreatic insufficiency. Interest in AIP has increased due to the recognition of radiological features such as irregular narrowing of the main pancreatic duct (MPD), pancreatic parenchyma alterations, IgG4 elevation, and lymphoplasmacytic infiltrate with abundant plasma cells. The diagnosis is made in patients with painless obstructive jaundice secondary to an inflammatory mass involving the biliary tract, accompanied by abdominal pain, weight loss, and increased levels of carbohydrate antigen 19-9 (CA19-9), mimicking pancreatic carcinoma. Tissue procurement is considered the “gold standard” for the diagnosis of AIP5. We report a case of IgG4 syndrome with a significant increase in CA19-9 level, acute pancreatitis, and enlargement of the pancreatic gland mimicking pancreatic carcinoma. An accurate diagnosis was obtained by EUS-FNA, and steroid treatment avoided unnecessary surgery.