Autoimmune pancreatitis is a recently characterized disease that still constitutes a diagnostic challenge, especially regarding differential diagnosis from neoplasia. Long-term outcome is poorly known. We herein report a case of a patient with autoimmune pancreatitis and 14 years of follow-up, and show its clinical, biochemical, and morphological characteristics. A 54-year-old female presented with obstructive jaundice and abdominal tenderness, as well as a mass at the pancreatic head on a CT scan, suggestive of pancreatic neoplasia. Surgery showed an increase of the whole pancreas, malignancy was intraoperatively ruled out, and a cholecystectomy and choledochoduodenostomy were carried out. The diagnosis was chronic pancreatitis. Over the following years different autoimmune complications developed, including asthma, salivary gland swelling, and sclerosing cholangitis, as well as recurrent episodes of jaundice, and exocrine and endocrine pancreatic failure. The development of these complications combined with the demonstration of high serum levels of IgG4 and carbonic anhydrase II led to a re-evaluation of the initial histology of the pancreas, leading to a final diagnosis of autoimmune pancreatitis: IgG4+ lymphoplasmacytic infiltrates, fibrosis, and obliterative phlebitis. New complications developed during the last few years: retroperitoneal fibrosis with portal hypertension, esophageal varices, and splenomegaly.