Autoimmune pancreatitis type 2: Mimicking pancreatic cancer

Autoimmune pancreatitis (AIP) is a rare disease, which comprises two distinct forms of steroid response chronic pancreatitis. AIP type 2 with no association to IgG level and more confined to the pancreas makes it hard to differentiate with pancreatic cancer preoperatively. Here, we present two cases that were preoperatively diagnosed as pancreatic cancer but turn out to be AIP type 2. The first case is a 55-year-old male with epigastric pain, body weight loss and obstructive jaundice. He also had elevated liver enzyme, but tumor marker and IgG4 level were within normal range. The image studies showed the pancreatic head mass. The pylorus-preserving pancreaticoduodenectomy was performed. The second case is a 35-year-old female with epigastric pain and fever. The laboratory data were within the normal range except elevated C-reactive protein level. The magnetic resonance cholangiopancreatography showed a lobulated mass at the pancreatic tail with regional lymphadenopathy. The laparoscopic distal pancreatectomy with splenectomy was arranged for suspect pancreatic neoplasm. In summary, we had reviewed several studies and concluded several steps to help differential AIP to pancreatic cancer. This may help reduce the unnecessary pancreatic resection in the future.