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| {{Refimprove|date=November 2009}} | | {{Short description|A form of pancreatitis caused by the body's immune system attacking the pancreas}} |
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| '''Autoimmune pancreatitis''' is an increasingly recognized type of [[chronic pancreatitis]] that can be difficult to distinguish from [[pancreatic carcinoma]] but which responds to treatment with [[corticosteroids]], particularly [[prednisone]].<ref>{{cite book |title=The autoimmune diseases |publisher=Academic Press |first1=Noel R. |last1=Rose|first2=Ian R. |last2=Mackay |edition=4th |year=2006 |isbn=978-0-12-595961-2 |page=783 }}</ref> There are two categories of AIP: Type 1 and Type 2, each with distinct clinical profiles.
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| Type 1 AIP is now regarded as a manifestation of [[IgG4-related disease]],<ref name=pmid22736240>{{cite journal |last1=Stone |first1=John H. |last2=Khosroshahi |first2=Arezou |last3=Deshpande |first3=Vikram |last4=Chan |first4=John K. C. |last5=Heathcote |first5=J. Godfrey |last6=Aalberse |first6=Rob |last7=Azumi |first7=Atsushi |last8=Bloch |first8=Donald B. |last9=Brugge |first9=William R. |last10=Carruthers |first10=Mollie N. |last11=Cheuk |first11=Wah |last12=Cornell |first12=Lynn |last13=Castillo |first13=Carlos Fernandez-Del |last14=Ferry |first14=Judith A. |last15=Forcione |first15=David |last16=Klöppel |first16=Günter |last17=Hamilos |first17=Daniel L. |last18=Kamisawa |first18=Terumi |last19=Kasashima |first19=Satomi |last20=Kawa |first20=Shigeyuki |last21=Kawano |first21=Mitsuhiro |last22=Masaki |first22=Yasufumi |last23=Notohara |first23=Kenji |last24=Okazaki |first24=Kazuichi |last25=Ryu |first25=Ji Kon |last26=Saeki |first26=Takako |last27=Sahani |first27=Dushyant |last28=Sato |first28=Yasuharu |last29=Smyrk |first29=Thomas |last30=Stone |first30=James R. |last31=Takahira |first31=Masayuki |last32=Umehara |first32=Hisanori |last33=Webster |first33=George |last34=Yamamoto |first34=Motohisa |last35=Yi |first35=Eunhee |last36=Yoshino |first36=Tadashi |last37=Zamboni |first37=Giuseppe |last38=Zen |first38=Yoh |last39=Chari |first39=Suresh |title=Recommendations for the nomenclature of IgG4-related disease and its individual organ system manifestations |journal=Arthritis & Rheumatism |volume=64 |issue=10 |pages=3061–7 |year=2012 |pmid=22736240 |pmc=5963880 |doi=10.1002/art.34593 }}</ref> and those affected have tended to be older and to have a high relapse rate. Type 1 is associated with pancreatitis, Sjogren syndrome, Primary sclerosing cholangitis and Inflammatory bowel disease. Patients with Type 2 AIP do not experience relapse, tend to be younger and not associated with systemic disease. AIP occurring in association with an [[autoimmune disorder]] has been referred to as "secondary" or "syndromic" AIP. AIP does '''not''' affect long-term survival.<ref>{{cite journal |last1=Sah |first1=Raghuwansh P. |last2=Chari |first2=Suresh T. |last3=Pannala |first3=Rahul |last4=Sugumar |first4=Aravind |last5=Clain |first5=Jonathan E. |last6=Levy |first6=Michael J. |last7=Pearson |first7=Randall K. |last8=Smyrk |first8=Thomas C. |last9=Petersen |first9=Bret T. |last10=Topazian |first10=Mark D. |last11=Takahashi |first11=Naoki |last12=Farnell |first12=Michael B. |last13=Vege |first13=Santhi S. |title=Differences in Clinical Profile and Relapse Rate of Type 1 Versus Type 2 Autoimmune Pancreatitis |journal=Gastroenterology |volume=139 |issue=1 |pages=140–8; quiz e12–3 |year=2010 |pmid=20353791 |doi=10.1053/j.gastro.2010.03.054 }}</ref>
| | '''Autoimmune pancreatitis''' (AIP) is a rare form of [[chronic pancreatitis]] characterized by an autoimmune inflammatory process that affects the [[pancreas]]. It is part of a spectrum of [[autoimmune diseases]] and is often associated with other systemic autoimmune conditions. |
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| ==Signs and symptoms== | | ==Classification== |
| AIP is relatively uncommon<ref>{{cite journal |last1=Chari |first1=Suresh T. |last2=Smyrk |first2=Thomas C. |last3=Levy |first3=Michael J. |last4=Topazian |first4=Mark D. |last5=Takahashi |first5=Naoki |last6=Zhang |first6=Lizhi |last7=Clain |first7=Jonathan E. |last8=Pearson |first8=Randall K. |last9=Petersen |first9=Bret T. |last10=Vege |first10=Santhi Swaroop |title=Diagnosis of Autoimmune Pancreatitis: The Mayo Clinic Experience |journal=Clinical Gastroenterology and Hepatology |volume=4 |issue=8 |pages=1010–6; quiz 934 |year=2006 |pmid=16843735 |doi=10.1016/j.cgh.2006.05.017 }}</ref> and is characterized by the following features:
| | Autoimmune pancreatitis is classified into two types: |
| # Scleral Icterus (yellow eyes), [[jaundice]] (yellow skin) which is usually painless, usually without acute attacks of [[pancreatitis]].
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| # Relatively mild symptoms, such as minimal weight loss or nausea.
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| # Increased serum levels of gamma globulins, [[immunoglobulin G]] (IgG) or IgG4.
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| # The presence of serum autoantibodies such as [[anti-nuclear antibody]] (ANA), anti-[[lactoferrin]] antibody, anti-[[carbonic anhydrase]] II antibody, and [[rheumatoid factor]] (RF).
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| # Contrast-enhanced CT demonstrates a diffusely enlarged (sausage-shaped) pancreas.
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| # Diffuse irregular narrowing of the main pancreatic duct, and stenosis of the intrapancreatic bile duct on [[endoscopic retrograde cholangiopancreatography]] (ERCP).
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| # Rare pancreatic calcification or cyst formation.
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| # Marked responsiveness to treatment with corticosteroids.
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| Two-thirds of patients present with either obstructive painless jaundice or a "mass" in the head of the pancreas mimicking carcinoma. It is mandatory to rule out carcinoma prior to making a diagnosis of AIP.{{citation needed|date=October 2016}}
| | * '''Type 1 AIP''': Also known as [[lymphoplasmacytic sclerosing pancreatitis]], this type is associated with [[IgG4-related disease]]. It is characterized by elevated serum [[IgG4]] levels and the presence of IgG4-positive [[plasma cells]] in the pancreas. |
| ==Histopathology==
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| Histopathologic examination of the pancreas reveals a characteristic lymphoplasmacytic infiltrate of [[CD4]]- or [[CD8]]-positive [[lymphocytes]] and IgG4-positive [[plasma cells]], and exhibits interstitial fibrosis and [[acinar cell]] atrophy in later stages. At the initial stages, typically, there is a cuff of lymphoplasma cells surrounding the ducts but also more diffuse infiltration in the lobular parenchyma. However, localization and the degree of duct wall infiltration are variable. Whereas histopathologic examination remains the primary method for differentiation of AIP from acute and chronic pancreatitis, [[lymphoma]], and cancer. By Fine Needle Aspiration (FNA) the diagnosis can be made if adequate tissue is obtained. In such cases, lymphoplasmacytic infiltration of the lobules are the key finding. Rarely, granulomatous reaction could be observed. It has been proposed that a cytologic smear primarily composed of acini rich in chronic inflammatory cells ([[lymphocytes]], [[plasma cells]]), with rare ductal [[epithelial cells]] lacking atypia, favors the diagnosis of AIP. The sensitivity and the specificity of these criteria for differentiating AIP from neoplasia are unknown. In cases of systemic manifestation of AIP, the pathologic features would be similar in other organs.{{citation needed|date=October 2016}}
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| ==Diagnosis==
| | * '''Type 2 AIP''': Also known as [[idiopathic duct-centric pancreatitis]], this type is not associated with IgG4-related disease. It is characterized by [[granulocytic epithelial lesions]] and is often associated with [[inflammatory bowel disease]], such as [[ulcerative colitis]]. |
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| ===Criteria=== | | ==Signs and symptoms== |
| Most recently the fourteenth Congress of the International Association of Pancreatology developed the International Consensus Diagnostic Criteria (ICDC) for AIP. The ICDC emphasizes five cardinal features of AIP which includes the imaging appearance of pancreatic parenchyma and the pancreatic duct, serum IgG4 level, other organ involvement with IgG4-related disease, pancreatic histology and response to steroid therapy.<ref name=pmid24758653>{{cite journal |last1=Khandelwal |first1=Ashish |last2=Shanbhogue |first2=Alampady Krishna |last3=Takahashi |first3=Naoki |last4=Sandrasegaran |first4=Kumaresan |last5=Prasad |first5=Srinivasa R. |title=Recent Advances in the Diagnosis and Management of Autoimmune Pancreatitis |journal=American Journal of Roentgenology |volume=202 |issue=5 |pages=1007–21 |year=2014 |pmid=24758653 |doi=10.2214/AJR.13.11247 }}</ref>
| | Patients with autoimmune pancreatitis may present with a variety of symptoms, including: |
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| In 2002, the Japanese Pancreas Society proposed the following diagnostic criteria for autoimmune pancreatitis:{{citation needed|date=October 2016}}
| | * [[Jaundice]] due to bile duct obstruction |
| ::I. Pancreatic imaging studies show diffuse narrowing of the main pancreatic duct with irregular wall (more than 1/3 of length of the entire pancreas).
| | * [[Abdominal pain]] |
| ::II. Laboratory data demonstrate abnormally elevated levels of serum gamma globulin and/or [[IgG]], or the presence of [[autoantibodies]].
| | * [[Weight loss]] |
| ::III. Histopathologic examination of the pancreas shows fibrotic changes with [[lymphocyte]] and [[plasma cell]] infiltrate.
| | * [[Diabetes mellitus]] |
| | * [[Pancreatic insufficiency]] leading to [[steatorrhea]] |
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| For diagnosis, criterion I (pancreatic imaging) must be present with criterion II (laboratory data) and/or III (histopathologic findings).<ref>{{cite journal |last1=Okazaki |first1=Kazuichi |last2=Uchida |first2=Kazushige |last3=Matsushita |first3=Mitsunobu |last4=Takaoka |first4=Makoto |title=How to diagnose autoimmune pancreatitis by the revised Japanese clinical criteria |journal=Journal of Gastroenterology |volume=42 Suppl 18 |issue= |pages=32–8 |year=2007 |pmid=17520221 |doi=10.1007/s00535-007-2049-5 }}</ref>
| | ==Diagnosis== |
| | | The diagnosis of autoimmune pancreatitis is based on a combination of clinical, serological, radiological, and histological findings. Key diagnostic criteria include: |
| Mayo Clinic has come up with five diagnostic criteria called '''HISORt''' criteria which stands for histology, imaging, serology, other organ involvement, and response to steroid therapy.<ref>{{cite journal |last1=O'Reilly |first1=Derek A |last2=Malde |first2=Deep J |last3=Duncan |first3=Trish |last4=Rao |first4=Madhu |last5=Filobbos |first5=Rafik |title=Review of the diagnosis, classification and management of autoimmune pancreatitis |journal=World Journal of Gastrointestinal Pathophysiology |volume=5 |issue=2 |pages=71–81 |year=2014 |pmid=24891978 |pmc=4025075 |doi=10.4291/wjgp.v5.i2.71 }}</ref>
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| ===Radiologic features===
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| [[Computed tomography]] (CT) findings in AIP include a ''diffusely enlarged hypodense'' pancreas or a focal mass that may be mistaken for a pancreatic malignancy.<ref name=pmid24758653/> A low-density, ''capsule-like rim on CT'' (possibly corresponding to an inflammatory process involving peripancreatic tissues) is thought to be an additional characteristic feature (thus the mnemonic: ''sausage-shaped''). [[Magnetic resonance imaging]] (MRI) reveals a diffusely decreased signal intensity and delayed enhancement on dynamic scanning. The characteristic [[Endoscopic retrograde cholangiopancreatography|ERCP]] finding is segmental or diffuse irregular narrowing of the main pancreatic duct, usually accompanied by an extrinsic-appearing stricture of the distal bile duct. Changes in the extrapancreatic bile duct similar to those of [[primary sclerosing cholangitis]] (PSC) have been reported.{{citation needed|date=October 2016}}
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| The role of [[endoscopic ultrasound]] (EUS) and EUS-guided [[fine-needle aspiration]] (EUS-FNA) in the diagnosis of AIP is not well described, and EUS findings have been described in only a small number of patients. In one study, EUS revealed a diffusely swollen and hypoechoic pancreas in 8 of the 14 (57%) patients, and a solitary, focal, irregular mass was observed in 6 (46%) patients. Whereas EUS-FNA is sensitive and specific for the diagnosis of pancreatic malignancy, its role in the diagnosis of AIP remains unclear.{{citation needed|date=October 2016}}
| | * Elevated serum IgG4 levels (particularly in Type 1 AIP) |
| | * Characteristic imaging findings on [[CT scan]] or [[MRI]], such as diffuse or focal pancreatic enlargement and a "sausage-shaped" pancreas |
| | * Histological examination showing lymphoplasmacytic infiltration and fibrosis |
| | * Response to [[corticosteroid]] therapy |
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| ==Treatment== | | ==Treatment== |
| AIP often completely resolves with steroid treatment. The failure to differentiate AIP from malignancy may lead to unnecessary pancreatic resection, and the characteristic lymphoplasmacytic infiltrate of AIP has been found in up to 23% of patients undergoing pancreatic resection for suspected malignancy who are ultimately found to have benign disease. In this subset of patients, a trial of steroid therapy may have prevented a [[Whipple procedure]] or complete [[pancreatectomy]] for a benign disease which responds well to medical therapy.<ref>{{cite journal |last1=Lin |first1=Lien-Fu |last2=Huang |first2=Pi-Teh |last3=Ho |first3=Ka-Sic |last4=Tung |first4=Jai-Nien |title=Autoimmune Chronic Pancreatitis |journal=Journal of the Chinese Medical Association |volume=71 |issue=1 |pages=14–22 |year=2008 |pmid=18218555 |doi=10.1016/S1726-4901(08)70067-4 }}</ref> "This benign disease resembles pancreatic carcinoma both clinically and radiographically. The diagnosis of autoimmune pancreatitis is challenging to make. However, accurate and timely diagnosis may preempt the misdiagnosis of cancer and decrease the number of unnecessary pancreatic resections."<ref name="ReferenceA">{{cite journal |last1=Law |first1=R. |last2=Bronner |first2=M. |last3=Vogt |first3=D. |last4=Stevens |first4=T. |title=Autoimmune pancreatitis: A mimic of pancreatic cancer |journal=Cleveland Clinic Journal of Medicine |volume=76 |issue=10 |pages=607–15 |year=2009 |pmid=19797461 |doi=10.3949/ccjm.76a.09039 |doi-access=free }}</ref> Autoimmune pancreatitis responds dramatically to [[corticosteroid]] treatment.<ref name="ReferenceA"/>
| | The primary treatment for autoimmune pancreatitis is corticosteroid therapy, which typically leads to rapid improvement in symptoms and imaging findings. In some cases, additional immunosuppressive agents such as [[azathioprine]] or [[mycophenolate mofetil]] may be used to maintain remission. |
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| If relapse occurs after corticosteroid treatment or corticosteroid treatment is not tolerated, [[immunomodulators]] may be used. Immunomodulators such as [[azathioprine]], and [[6-mercaptopurine]] have been shown to extend remission of autoimmune pancreatitis after corticosteroid treatment. If corticosteroid and immunomodulator treatments are not sufficient, [[rituximab]] may also be used. Rituximab has been shown to induce and maintain remission.<ref>{{cite journal |last1=Hart |first1=Phil |last2=Chari |first2=Suresh |year=2013 |title=Immunomodulators and Rituximab in the Management of Autoimmune Pancreatitis |journal=Pancreapedia |doi=10.3998/panc.2013.20 |doi-access=free }}</ref>
| | ==Prognosis== |
| | With appropriate treatment, the prognosis for autoimmune pancreatitis is generally good. However, relapses can occur, and long-term follow-up is necessary to monitor for recurrence and manage any associated autoimmune conditions. |
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| ==Controversies in nomenclature== | | ==Related pages== |
| As the number of published cases of AIP has increased, efforts have been focused on defining AIP as a distinct clinical and pathologic entity and toward developing some generally agreed upon diagnostic criteria and nomenclature. Terms frequently encountered are autoimmune or autoimmune-related pancreatitis, lymphoplasmacytic sclerosing pancreatitis, idiopathic tumefactive chronic pancreatitis, idiopathic pancreatitis with focal irregular narrowing of the main pancreatic duct, and non-alcoholic duct destructive chronic pancreatitis. There are also a large number of case reports employing descriptive terminology such as pancreatitis associated with [[Sjögren’s syndrome]], [[primary sclerosing cholangitis]], or [[inflammatory bowel disease]]. Some of the earliest cases were reported as pancreatic pseudotumor or [[pseudolymphoma]].{{citation needed|date=October 2016}}
| | * [[Pancreatitis]] |
| | * [[Chronic pancreatitis]] |
| | * [[IgG4-related disease]] |
| | * [[Autoimmune disease]] |
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| ==References==
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| {{Reflist}}
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| == External links ==
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| {{Medical resources
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| | ICD10 = K86.1
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| | Orphanet = 103919
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| [[Category:Pancreas disorders]]
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| [[Category:Autoimmune diseases]] | | [[Category:Autoimmune diseases]] |
| [[Category:IgG4-related disease]] | | [[Category:Pancreatic disorders]] |
| [[Category:Steroid-responsive inflammatory conditions]]
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| {{dictionary-stub1}}
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| <gallery>
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| File:Diffuse autoimmune pancreatitis.jpg|Diffuse autoimmune pancreatitis
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| </gallery>
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A form of pancreatitis caused by the body's immune system attacking the pancreas
Autoimmune pancreatitis (AIP) is a rare form of chronic pancreatitis characterized by an autoimmune inflammatory process that affects the pancreas. It is part of a spectrum of autoimmune diseases and is often associated with other systemic autoimmune conditions.
Classification
Autoimmune pancreatitis is classified into two types:
Signs and symptoms
Patients with autoimmune pancreatitis may present with a variety of symptoms, including:
Diagnosis
The diagnosis of autoimmune pancreatitis is based on a combination of clinical, serological, radiological, and histological findings. Key diagnostic criteria include:
- Elevated serum IgG4 levels (particularly in Type 1 AIP)
- Characteristic imaging findings on CT scan or MRI, such as diffuse or focal pancreatic enlargement and a "sausage-shaped" pancreas
- Histological examination showing lymphoplasmacytic infiltration and fibrosis
- Response to corticosteroid therapy
Treatment
The primary treatment for autoimmune pancreatitis is corticosteroid therapy, which typically leads to rapid improvement in symptoms and imaging findings. In some cases, additional immunosuppressive agents such as azathioprine or mycophenolate mofetil may be used to maintain remission.
Prognosis
With appropriate treatment, the prognosis for autoimmune pancreatitis is generally good. However, relapses can occur, and long-term follow-up is necessary to monitor for recurrence and manage any associated autoimmune conditions.
Related pages
