Typical Case 6:Autoimmune Pancreatitis
Brief history:a 55-year-old man complained of recurrent upper abdominal pain radiating to the back with jaundice occasionally for 3 years.ERCP+common bile duct dilatation was performed in the local hospital according to the diagnosis of inflammatory stricture of the common bile duct.In July 2010，the pain recurred concurrently with fever and CT in the local hospital revealed the dilatation of both intrahepatic and extrahepatic bile ducts，distal biliary obstruction，and enlargement of the pancreas.Therefore，ERCP+bile duct stent placement was carried out，followed by stent removal 3 weeks later.Shortly afterwards，the patient was admitted to our department for further management.
Physical examination:mild tenderness in the epigastrium without rebound tenderness or guarding，a movable lymph node about 1.0 cm3 palpable in the right mandible，no significant jaundice.
Laboratory parameters:CA 19-9 16.5 IU/mL，IgG4 9.84 g/L，IgE 585 IU/mL，negative results of autoimmune antibodies.
CT:enlargement of the pancreatic body and tail with poorly defined margins，peripancreatic fluid collections，thickening of peripancreatic fatty tissue（Fig.13.23a），gastric varices（Fig.13.23b），and abdominal aorta compressed below the opening of renal artery（Fig.13.23c）.
EUS:hypoechoic and heterogeneous area（3.4*4.0 cm）in the pancreatic body and tail with poor demarcation，involvement of splenic vein，an enlarged lymph node about 1.0 cm3 adjacent to proximal pancreatic duct with normal caliber.
FNA:A few pancreatic acini，no tumor cells.(https://www.daowen.com)
Diagnosis:autoimmune pancreatitis.
Treatment process:after oral prednisone at a starting dose of 30 mg/day for 30 days，the level of IgG4 returned to 4.41 g/L and CT showed normal morphology of pancreas，improvement of gastric varices and the compression of abdominal aorta（Fig.13.24）.Then，prednisone was used by a taper of 5 mg per week.Discomfort had not occurred since drug withdrawal.
Fig.13.23 （a）CT revealed enlargement of the pancreatic body and tail with poorly defined margins，peripancreatic fluid collections，and thickening of peripancreatic fatty tissue.（b）CT revealed gastric varices.（c）CT revealed abdominal aorta compressed below the opening of renal artery
Fig.13.24 CT showed normal morphology of pancreas，improvement of gastric varices and the compression of abdominal aorta