Chronic pancreatitis: focal pancreatitis or cancer? Is there a role for FNA/biopsy? Autoimmune pancreatitis

Autoimmune chronic pancreatitis

BACKGROUND

Autoimmune pancreatitis (AIP) is a unique form of chronic pancreatitis that is characterized by swelling of the pancreas, narrowing of the main pancreatic duct (MPD), elevation of serum gamma globulin, or immunoglobulin G or presence of autoantibody, lymphoplasmacytic infiltration and dense fibrosis on histopathology. It is responsive to steroid therapy. The incidence of AIP can reach 5-6% of chronic pancreatitis. It can present as obstructive jaundice, body weight loss, and pancreas head mass mimicking pancreatic cancer. The recognition of AIP can avoid major surgery such as pancreatic resection.

METHODS

From May 2003 to July 2007, a total of 5 cases of AIP were reviewed retrospectively. The diagnosis was made on imaging study, serology, steroid response and/or histology if surgery was carried out.

RESULTS

There were 2 male and 3 female patients, with a mean age of 61 (39-75) years. Atypical AIP was found in the first case and typical AIP in the remaining 4. The presenting clinical pictures were mild epigastric pain, obstructive jaundice, and loss of body weight in 4 cases, with associated autoimmune disease in 1. Diffuse or long segmental enlargement of the pancreas without peripancreatic fat infiltration was found in all patients except 1 who only had focal pancreatic head enlargement. Distal common bile duct (CBD) stricture was seen in 4 cases and the median CBD stricture length was 1.2 (0.5-2.5) cm. Multiple narrowing of the whole MPD was seen in 2 cases, focal narrowing of the MPD in 2 and long segmental narrowing of the MPD in 1. Serum immunoglobulin G tests were done in 4 cases and were elevated in all. Antinuclear antibody was positive in 3. The first case was operated on after a preoperative diagnosis of suspicious pancreatic head tumor. The subsequent 3 cases were diagnosed correctly as AIP. The last case presented with distal CBD stricture and hypoechoic lesion in the pancreas head on endoscopic ultrasound, with only borderline pancreatic enlargement on computed tomography, and he was operated on. Retrospective endoscopic retrograde pancreatogram review revealed MPD narrowing in the pancreatic body. Endoscopic retrograde brush cytology was performed and was negative for malignancy in 3 cases. Steroid therapy was given in 3 and was responsive, but there were 2 recurrences.

CONCLUSION

AIP should be a differential diagnosis in distal CBD stricture and pancreatic head mass when the patient has: (1) diffuse or long segmental enlargement of the pancreas without peripancreatic fat infiltration, with multiple narrowing of the MPD without much upstream dilatation, or narrowing of the MPD not corresponding to the region of CBD stricture; and (2) abnormal immunoserologic tests.

Is pancreatic core biopsy sufficient to diagnose autoimmune chronic pancreatitis?

OBJECTIVES

This study aimed to evaluate the adequacy of pancreatic core biopsy in histological diagnosis of autoimmune chronic pancreatitis (AIP).

METHODS

Histopathologic study as well as immunohistochemical staining using anti-IgG4 antibody was done with pancreatic tissue specimens of 26 AIP patients (19 transabdominal ultrasound (US)-guided core biopsies, 3 intraoperative wedge biopsies, and 4 surgical resections). Eight patients with alcoholic chronic pancreatitis and 10 patients with pancreatic cancer served as controls.

RESULTS

Lymphoplasmacytic sclerosing pancreatitis (LPSP) histology was observed in 26% (5/19) of US-guided core biopsy specimens, 33% (1/3) of open biopsy specimens, and all 4 resection specimens in AIP patients. None of the patients in the control group showed the full spectrum of changes of LPSP. Abundant IgG4-positive cells (>10 cells/high-power field) in the pancreas were observed in 21% (4/19) of AIP patients with US-guided core biopsy specimen. Abundant IgG4-positive cells in the pancreas were also observed in 2 of 8 patients with chronic alcoholic pancreatitis and 1 of 10 patients with pancreatic cancer.

CONCLUSIONS

Transabdominal US-guided pancreatic core biopsy may not provide enough tissue to evaluate characteristic histopathologic features of AIP that include LPSP or abundant IgG4-positive cell infiltration. The LPSP histology may be specific to AIP, but abundant IgG4-positive cells in the pancreas may not.

T-cell regulatory gene CTLA-4 polymorphism/haplotype association with autoimmune pancreatitis

BACKGROUND

Autoimmune pancreatitis (AIP) is a distinct disease entity of chronic pancreatitis. Cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) is a key negative regulator of the T-cell immune response, and its gene is highly polymorphic. Many positive associations between cytotoxic T-lymphocyte-associated protein 4 (CTLA4) single-nucleotide polymorphisms and various autoimmune diseases have been identified. We investigated possible genetic associations of CTLA4 in a Chinese population with AIP.

METHODS

We performed genotyping for CTLA4 (49 A/G, -318 C/T, and CT60 A/G) and tumor necrosis factor (TNF)-alpha promoter (-857 C/T, -863 C/A, and -1031 C/T) by use of PCR sequence-specific primers and direct sequencing, respectively, in 46 patients with AIP, 78 patients with chronic calcifying pancreatitis (CCP), and 200 healthy individuals.

RESULTS

We found a significant increase in CTLA4 49A carriers in patients with AIP compared with healthy individuals (78.3% vs 48%; P <0.0001). The frequency of CTLA4 49A was also significantly higher in patients with AIP compared with CCP (78.3% vs 37.1%; P <0.0001). CTLA4 49A conferred a higher risk of AIP [with CCP, odds ratio (OR) 7.20; P <0.0001]. The -318C/+49A/CT60G haplotype was associated with a higher susceptibility to AIP (OR 8.53; P = 0.001). The TNF-alpha promoter -863A was associated with extrapancreatic involvement in patients with AIP.

CONCLUSION

CTLA-4 49A polymorphism and -318C/+49A/CT60G haplotype are associated with AIP in a Chinese population.

Endoscopic retrograde cholangiopancreatography and endoscopic ultrasound for diagnosis of chronic pancreatitis

The diagnosis of chronic pancreatitis is based on altered pancreatic morphology and function. A spectrum of disease exists, and milder forms of disease may be missed by CT but demonstrated by endoscopic retrograde cholangiopancreatography (ERCP) or endoscopic ultrasound (EUS). The accuracy of ERCP and EUS for diagnosis of "minimal change" or "early" chronic pancreatitis is controversial, particularly when the results from these imaging procedures are discordant with each other or with tests of pancreatic function; in some cases ERCP and EUS should be considered indeterminate for diagnosis. This review discusses recent data concerning the accuracy of ERCP and EUS for diagnosis of chronic pancreatitis, the use of EUS fine-needle aspiration for differential diagnosis of pancreatic masses, and the use of EUS and EUS-guided TruCut biopsy for diagnosis of autoimmune pancreatitis.

Autoimmune pancreatitis

Autoimmune pancreatitis is a rare systemic fibrotic inflammatory disorder that can affect organs such as the bile ducts, salivary glands, and retroperitoneal lymph nodes, in addition to the pancreas. Morphological characteristics of autoimmune pancreatitis include a diffusely enlarged 'sausage-shaped' pancreas and an irregularly narrowed duct of Wirsung. According to the revised Japan Pancreas Society criteria, the diagnosis of autoimmune pancreatitis requires that one or more secondary serologic or histologic criteria are also met: the presence of autoantibodies, elevated levels of gamma-globulins, IgG or IgG(4), a lymphoplasmacytic infiltrate, or pancreatic fibrosis. The presence in any affected organ of a lymphoplasmacytic inflammatory infiltrate containing greater than 10 IgG(4)-positive cells per high-power field is pathognomonic for autoimmune pancreatitis. Precise data on the incidence and prevalence of autoimmune pancreatitis are currently not available because most reports involve either limited patient series or resection specimen cohorts. New diagnostic tools and further studies of the underlying pathophysiology and prognosis of autoimmune pancreatitis are needed for adequate and effective treatment strategies to be developed. The most crucial issue when caring for patients with suspected autoimmune pancreatitis is to differentiate autoimmune pancreatitis from pancreatic carcinoma, because pancreatic carcinoma requires surgery, whereas autoimmune pancreatitis responds well to steroid treatment.

Autoimmune pancreatitis

Autoimmune pancreatitis (AIP) is a benign, IgG4-related, fibroinflammatory form of chronic pancreatitis that can mimic pancreatic ductal adenocarcinoma both clinically and radiographically. Laboratory studies typically demonstrate elevated serum IgG4 levels and imaging studies reveal a diffusely or focally enlarged pancreas with associated diffuse or focal narrowing of the pancreatic duct. The pathologic features include periductal lymphoplasmacytic inflammation, obliterative phlebitis, and abundant IgG4-positive plasma cells. The treatment of choice for AIP is steroid therapy. Diagnostic criteria for AIP have been proposed that incorporate histologic, radiographic, serologic, and clinical information.

The patient with unexplained elevated serum liver enzymes

The pattern of elevated serum liver enzymes in symptomatic or asymptomatic patients allows for an initial classification of liver diseases into cholestatic or hepatocellular diseases. A female patient with extrahepatic cholestasis due to segmental bile duct strictures and a localized mass lesion within the pancreas is presented. Although many diagnostic procedures were performed in this case the diagnosis was not obtained before surgical laparotomy was initiated with bioptic sampling from bile ducts, lymph nodes and pancreatic tissue. Microscopic examination of the specimen revealed extensive biliary and pancreatic scarring together with periductal infiltrates composed of lymphocytes and plasma cells consistent with sclerosing cholangitis in systemic autoimmune pancreatitis. The patient completely recovered upon treatment with prednisone and azathioprine. The difficult approach to the final diagnosis is discussed in light of established and modern diagnostic tools.

Diagnostic criteria for autoimmune chronic pancreatitis

Autoimmune chronic pancreatitis (AIP) is a clinically attractive entity because of its dramatic response to oral steroid therapy. Recently, as awareness of AIP is increasing, more cases are being reported. However, there are still no established worldwide diagnostic criteria for AIP. Since the Japan Pancreas Society (JPS) published diagnostic criteria for autoimmune chronic pancreatitis in the year 2002, increased attention toward this relatively new disease entity has enabled more cases of AIP to be correctly diagnosed. As previously unrecognized or misdiagnosed cases of autoimmune chronic pancreatitis are found, an increasing number of cases that are not in full accordance with the JPS diagnostic criteria are revealed. As a result, some groups have developed and cited their own criteria in the reporting of autoimmune chronic pancreatitis. The absence of consistent, uniform criteria has made comparison of different cases diagnosed under various guidelines difficult. In this review, we discuss and compare the four current sets of diagnostic criteria, focusing on their individual strengths and weaknesses.

The diagnostic criteria for autoimmune chronic pancreatitis: it is time to make a consensus

Autoimmune chronic pancreatitis (AIP) is increasingly being recognized as a worldwide entity. In 2002, the Japan Pancreas Society published diagnostic criteria for AIP. Since then, increased attention toward this relatively new disease entity has enabled more cases of AIP to be correctly diagnosed, allowing for proper management and avoidance of surgery. Retrospective inclusion of previously unrecognized or misdiagnosed cases of AIP has revealed an increasing number of cases that are not in full accordance with the Japanese diagnostic criteria. As a result, some groups have developed and cited their own criteria in the reporting of AIP, and the Japan Pancreas Society criteria have also undergone revision recently. The absence of consistent and uniform criteria has made the comparison of different cases diagnosed under various guidelines difficult. In this review, we discuss and compare the 4 current diagnostic criteria, focusing on their own strength and weakness with the aim of providing a framework for the development of unified criteria that represent an international consensus.

Autoimmune pancreatitis: proposal of IgG4-related sclerosing disease

Autoimmune pancreatitis (AIP) is a peculiar type of pancreatitis of presumed autoimmune etiology. Many new clinical aspects of AIP have been clarified during the past 10 years, and AIP has become a distinct entity recognized worldwide. However, its precise pathogenesis or pathophysiology remains unclear. As AIP dramatically responds to steroid therapy, accurate diagnosis of AIP is necessary to avoid unnecessary surgery. Characteristic dense lymphoplasmacytic infiltration and fibrosis in the pancreas may prove to be the gold standard for diagnosis of AIP. However, since it is difficult to obtain sufficient pancreatic tissue, AIP should be diagnosed currently based on the characteristic radiological findings (irregular narrowing of the main pancreatic duct and enlargement of the pancreas) in combination with serological findings (elevation of serum gamma-globulin, IgG, or IgG4, along with the presence of autoantibodies), clinical findings (elderly male preponderance, fluctuating obstructive jaundice without pain, occasional extrapancreatic lesions, and favorable response to steroid therapy), and histopathological findings (dense infiltration of IgG4-positive plasma cells and T lymphocytes with fibrosis and obliterative phlebitis in various organs). It is apparent that elevation of serum IgG4 levels and infiltration of abundant IgG4-positive plasma cells into various organs are rather specific to AIP patients. We propose a new clinicopathological entity, "IgG4-related sclerosing disease", and suggest that AIP is a pancreatic lesion reflecting this systemic disease.