Autoimmune Pancreatitis- A Mimicker of Pancreatic Cancer

Although rare, autoimmune pancreatits, also known as lymphoplasmacytic sclerosing pancreatits, can clinically mimic pancreatic cancer.  Autoimmune pancreatitis, as the name suggests is a disease that is: 1) characterized by inflammation of the pancreas (“pancreatitis”), and 2) believed to be caused by the body’s immune system abnormally reacting against the body’s own cells in the pancreas (“auto” means self or same). 

Autoimmune pancreatits is pretty darn rare.  A hospital survey from Japan, estimated that less than one person per 100,000 has autoimmune pancreatitis.  Most patients are elderly, with an average age of 68, but teenagers have been diagnosed with the disease as well as octogenarians.  Unlike most other autoimmune diseases, men develop autoimmune pancreatitis more commonly than do women (the male to female ratio is 4 to 1).  Most patients do not present with signs and symptoms of pancreatitis, instead most patients develop signs and symptoms that are more suggestive of pancreatic cancer.  These would include jaundice (an abnormal yellowing of the white part of the eyes), and diabetes mellitus (sugar diabetes).  A CT scan is often taken and it can reveal a localized “sausage-like” enlargement of the pancreas, a finding suggestive of pancreatic cancer.  As a result, many patients with autoimmune pancreatitis are often felt to have pancreatic cancer.  A blood test can be helpful as many, although certainly not all, patients with autoimmune pancreatitis have elevated serum “IgG4 levels.” 


Autoimmune pancreatitis can be associated with immune injury to other organs, and some patients also develop a swelling of their salivary glands, kidney problems, and a scarring of the internal abdomen (called retroperitoneal fibrosis). 


Because autoimmune pancreatits so closely mimics pancreatic cancer, many patients with autoimmune pancreatits are taken to surgery and have the abnormal portion of their pancreas removed.  In these cases the pathology of the pancreas can be diagnostic.  It shows three features- 1) a mixed inflammatory cell infiltrate composed of plasma cells and lymphocytes, 2) inflammation centered  on the pancreatic ducts, and 3) inflammation involving the veins of the pancreas (“venulitis”).  In questionable cases a special stain for IgG4 can be performed and it will label the inflammatory cell infiltrate in the pancreas helping to establish the diagnosis.


Autoimmune pancreatits is important to recognize because some patients respond to steroid therapy (30–40 mg/day of prednisolone).  As clinicians become familiar with this rare disease it is hoped that more and more patients will be diagnosed without the need for surgery.


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5 Responses to “Autoimmune Pancreatitis- A Mimicker of Pancreatic Cancer”

  1. Yvonne Says:

    Don’t know where to turn anymore , GI , Rheum. , Urolog. Family,DRs.???? I was told I have sjogrens recently . I was hoping that it would explain alot of symptoms i’ve had in the past, that have yet to be diagnosed .Like this pain in my (L) upper quad, under my rib cage that radiates to my back ,I get nausea @ I eat nothing relieves it …i’ve had ABD CT , Hepatic, all Normal the only thing out of sort is an elevated Lipase 464 at it’s highest.

  2. Dr. Hruban Says:

    Yvonne: I am sorry to learn of your illness. Since you have been diagnosed with Sjogrens, I think a rheumatologist may be a good place to start. Since the pain involves your abdomen and is associated with nausea, a gastroenterologist is also another good place to start. Sometimes these require a good multi-disciplinary approach. My sincere best wishes to you. Dr. Hruban

  3. Dr. Ralph Hruban Says:

    Sorry to hear about his problems. I am not aware of a link between Lupus and Autoimmune Pancreatitis. Certainly, in general, patients with one autoimmune disease are often at risk for other autoimmune diseases. My sincere best wishes to you both. Dr. Hruban

  4. Ritu Says:

    Is there any information on the numbers of whipple’s or pancreatic resections being performed for type 2 autoimmune pancreatitis for presumed cancer. The diagnosis seems to be very difficult based on imaging, FNA and serology.
    With an elevated CA 19-9 in the 300’s, dilated pancreatic duct(6-7 mm) with a cut off in the head, pancreatic head enlargement/and pancreatitis with a atrophic body and tail, elevated CEA (750) in the pancreatic fluid and FNA suggestive of ductal adenoca in a patient presenting with abdominal pain and pancreatitis, it was hard to not consider a whipple’s for pancreatic cancer. The final path on the whipple’s specimen was reported as AIP type 2!!

  5. Dr. Ralph Hruban Says:

    We reported that 24% of Whipple resections without cancer were performed on people who had autoimmune pancreatitis that mimicked a pancreatic tumor (see reference below). My sincere best wishes to you for a speedy recovery. RHH

    Am J Surg Pathol. 2003 Jan;27(1):110-20.
    Pancreaticoduodenectomy (Whipple resections) in patients without malignancy: are they all ‘chronic pancreatitis’?
    Abraham SC, Wilentz RE, Yeo CJ, Sohn TA, Cameron JL, Boitnott JK, Hruban RH.