Difficulty in diagnosing autoimmune pancreatitis by imaging findings

Autoimmune pancreatitis complicated by carcinoma of the pancreatobiliary system: a case report and review of the literature

We present the case of a 67-year-old woman who developed a metastatic adenocarcinoma of the pancreatobiliary system shortly after the histologically confirmed diagnosis of autoimmune pancreatitis (AIP). This case highlights the need for increased alertness not only in differentiating AIP from pancreatic cancer at the time of diagnosis, but also to exclude concomitant malignancies of the pancreatobiliary system in the management of histologically confirmed AIP.

The therapeutic strategy for autoimmune pancreatitis is subject to the endoscopic features of the duodenal papilla

Autoimmune pancreatitis (AIP) often presents with a swollen duodenal papilla, however, the clinical significance of the duodenal papilla in AIP has not been fully elucidated. Data have shown swollen duodenal papillae shaped like a pear and/or with a submucosal tumor having IgG4-bearing plasma cells. Immunohistopathology has potentially verified duodenal papillitis associated with AIP. FOXP3-positive lymphocytes are also recognized in AIP. AIP has shown spontaneous remission and relapse irrelevance to corticosteroid therapy. The results of a multivariate analysis revealed the absence of a swollen duodenal papilla as the only significant independent factor predictive of spontaneous remission in AIP cases. In addition, the results of another multivariate analysis revealed the presence of a swollen duodenal papilla and the presence of extrapancreatic lesions as the significant independent factors predictive of relapse in these cases. Results suggest that the lack of a swollen duodenal papilla is a predictive factor for spontaneous remission, and thus negates the need to administer corticosteroids in those AIP patients. In contrast, a swollen duodenal papilla and the presence of extrapancreatic lesions are risk factors for relapse, and those AIP patients are candidates for maintenance corticosteroid therapy to reduce relapse. Therefore, the therapeutic strategy such as the indication for corticosteroid administration is subject to the endoscopic features of the duodenal papilla.

IgG4-related sclerosing cholangitis and autoimmune pancreatitis: histological assessment of biopsies from Vater's ampulla and the bile duct

BACKGROUND AND AIM

Autoimmune pancreatitis is commonly associated with immunoglobulin (Ig) G4-related sclerosing cholangitis (IgG4-SC). The discrimination between IgG4-SC and pancreatobiliary malignancies or primary sclerosing cholangitis (PSC) is now an important issue. The present study was carried out to examine the usefulness of endoscopic biopsies from Vater's ampulla and the bile duct to diagnose IgG4-SC.

METHODS

The present study included 29 IgG4-SC patients (26 with both pancreatitis and cholangitis, and 3 with cholangitis only), 6 PSC patients, and 27 pancreatobiliary carcinoma patients. All patients underwent endoscopic biopsies from Vater's ampulla and the common bile duct. Biopsied specimens were histologically examined using immunostaining for IgG4.

RESULTS

For the ampullary and bile duct biopsies, the IgG4-SC samples had a significantly greater number of IgG4-positive plasma cells than the PSC or pancreatobiliary carcinoma specimens. In addition, bile duct biopsies from five patients (17%) with IgG4-SC showed diffuse inflammatory cell infiltration with irregular fibrosis corresponding to the histological features of lymphoplasmacytic sclerosing pancreatocholangitis. Based on the threshold of 10 IgG4-positive plasma cells per high power field, the diagnostic rates of the ampullar and bile duct biopsies were both 52% (15/29 cases). Twenty-one patients (72%) had more than 10 IgG4-positive plasma cells in at least one biopsy. The bile duct biopsy was significantly valuable for IgG4-SC patients with swelling of the pancreatic head.

CONCLUSION

The present study suggested that ampullar and bile duct biopsies are useful for diagnosing IgG4-SC.

Differentiation between autoimmune pancreatitis and pancreatic carcinoma based on endoscopic retrograde cholangiopancreatography findings

OBJECTIVE

We have reviewed the endoscopic retrograde cholangiopancreatography (ERCP) images of patients with autoimmune pancreatitis (AIP) and pancreatic carcinoma (Pca) in an attempt to identify findings that would facilitate making a differential diagnosis between AIP and Pca.

METHODS

The study cohort consisted of 39 patients diagnosed with AIP and 62 patients diagnosed with Pca. The ERCP findings in the pancreatic duct and biliary tract were compared between the two groups.

RESULTS

The ERCP images revealed that AIP patients had a higher prevalence of narrowing of the main pancreatic duct (MPD) for ≥ 3 cm of its length and a higher prevalence for the presence of side branches in the narrowed portion of the MPD than Pca patients (p < 0.001 and p < 0.001, respectively). In contrast, the prevalence of an upstream MPD having a maximal diameter ≥ 4 cm was significantly higher in the Pca patient group (p < 0.001). The discriminant analysis identified three significant factors: (1) whether or not side branches were present; (2) total length of the narrowed portion of the MPD; (3) maximal diameter of the upstream MPD. It was impossible to differentiate Pca from AIP in the two Pca patients in whom ERCP revealed both narrowing of the MPD for > 5 cm of its length and the presence of side branches.

CONCLUSIONS

Among our patient cohort, the ERCP findings in terms of the length of the narrowed portion of the MPD, the presence of side branches, and maximal diameter of the upstream MPD enabled differential diagnosis between AIP and Pca in most of the cases. However, it must be borne in mind that some Pca patients have ERCP findings similar to those of AIP patients.

IgG4 immunostaining of duodenal papillary biopsy specimens may be useful for supporting a diagnosis of autoimmune pancreatitis

BACKGROUND

Autoimmune pancreatitis (AIP) is now considered to be part of an immunoglobulin G4 (IgG4)-related systemic fibroinflammatory disease.

OBJECTIVE

We evaluated whether IgG4 immunostaining of duodenal papillary biopsy specimens is useful for supporting a diagnosis of AIP.

DESIGN

A prospective study.

SETTING

A tertiary academic center.

PATIENTS/INTERVENTIONS

We obtained 2 forceps biopsy specimens from the major duodenal papilla (MDP) of 19 symptomatic AIP patients during ERCP before steroid administration. As a control, biopsy specimens were obtained from the MDP of patients with pancreatic cancer (n = 35), cholangiocarcinoma (n = 20), ampullary cancer (n = 11), ordinary chronic pancreatitis (n = 18), and AIP in remission (n = 16) and immunohistochemically examined.

MAIN OUTCOME MEASUREMENTS

Specimens were considered positive for IgG4 immunostaining if there were more than 10 IgG4-positive plasma cells per high-power field.

RESULTS

Positive IgG4 immunostaining of the MDP was found in 10 (53%) of 19 symptomatic AIP patients, but was absent in the control groups. Among symptomatic AIP patients (n = 19), 5 (83%) of 6 AIP patients with elevated serum IgG4 levels exhibited positive IgG4 staining of the MDP, whereas 5 (38%) of 13 AIP patients with normal serum IgG4 levels showed positive IgG4 staining of the MDP. Nine of 19 symptomatic AIP patients also underwent pancreatic biopsy, and positive IgG4 immunostaining of the MDP was observed in patients with positive pancreas IgG4 staining (4/6, 67%), but not in patients with negative pancreas IgG4 staining (0/3).

LIMITATIONS

Small symptomatic AIP patient population.

CONCLUSIONS

Positive IgG4 immunostaining of the MDP was an extremely specific and moderately sensitive tool for the diagnosis of AIP. IgG4 immunostaining of the MDP may be useful for supporting a diagnosis of AIP, especially when AIP is suspected clinically but serum IgG4 levels are normal or pancreatic tissue is not available.

Autoimmune pancreatitis complicated by an infected pseudocyst

A 53-year-old man was admitted due to upper abdominal pain. He had been diagnosed with autoimmune pancreatitis (AIP) 4 years previously and had been taking steroids for maintenance therapy since that time. Abdominal computed tomography revealed multiple pseudocysts in the head of the pancreas and a dilated pancreatic duct with mottled calcifications around the pseudocyst. Despite the continuation of steroid therapy for 4 months, the size of the pseudocyst increased further and diffuse calcifications developed throughout the pancreas. He was readmitted due to severe abdominal pain and a high fever, and endoscopic drainage of the pancreatic pseudocyst was performed. Two months after the internal drainage, the pseudocyst disappeared and his symptoms subsided. There are few reports concerning AIP complicated by the formation of pseudocysts. We report this case to emphasize that AIP can be complicated by the development of pseudocysts with progression to chronic pancreatitis, accompanied by multiple calcifications.

Japanese consensus guidelines for management of autoimmune pancreatitis: I. Concept and diagnosis of autoimmune pancreatitis

As the number of patients with autoimmune pancreatitis (AIP) is increasing in Japan, practical guidelines for managing AIP need to be established. Three committees [the professional committee for developing clinical questions (CQs) and statements by Japanese specialists, the expert panelist committee for rating statements by the modified Delphi method, and the evaluating committee of moderators] were organized. Fifteen AIP specialists extracted specific clinical statements from a total of 871 articles in the literature using a PubMed search (1963-2008) and a secondary database, and developed the CQs and statements. The expert panelists individually rated these clinical statements using a modified Delphi approach in which a clinical statement receiving a median score greater than 7 on a 9-point scale from the panel was regarded as valid. The professional committee developed 13, 6, 6, and 11 CQs and statements for the concept and diagnosis, extra-pancreatic lesions, differential diagnosis and treatment, respectively. The expert panelists regarded them as valid after two-round modified Delphi approaches.After evaluation by the moderators, the Japanese clinical guidelines for AIP were established. The digest versions of the present guidelines have been published in the official journal of the Japan Pancreas Society, "Pancreas." Full versions divided into three series are scheduled to be published in the present and followings two issues in the Journal of Gastroenterology with approval of Professor Go VLW, the Editor-in-Chief of "Pancreas."

Endoscopic transpapillary intraductal ultrasonography and biopsy in the diagnosis of IgG4-related sclerosing cholangitis

PURPOSE

IgG4-related sclerosing cholangitis (IgG4-SC) is one of the diseases associated with autoimmune pancreatitis. Several cases of IgG4-SC showed no pancreas abnormalities and it was difficult to distinguish cholangiocarcinoma. We aimed to clarify the findings of transpapillary intraductal ultrasonography (IDUS) and bile duct biopsy in the patients with IgG4-SC.

METHODS

We retrospectively evaluated the findings of transpapillary IDUS and biopsy in 23 consecutive patients with IgG4-SC at Nagoya City University Hospital between 2004 and 2008. Eleven patients with cholangiocarcinoma were enrolled as a control group.

RESULTS

IDUS findings of circular-symmetric wall thickness, a smooth outer margin, a smooth inner margin and a homogeneous internal echo in the stricture were significantly higher in IgG4-SC than in cholangiocarcinoma (p < 0.01). The wall thickness in IgG4-SC in regions of non-stricture on the cholangiogram was significantly greater than that in cholangiocarcinoma (p < 0.0001). A bile duct wall thickness exceeding 0.8 mm in regions of non-stricture on the cholangiogram was highly suggestive of IgG4-SC (sensitivity 95.0%, specificity 90.9%, accuracy 93.5%). In transpapillary biopsy, lymphoplasmacytic infiltration was observed in 100% (17/17), fibrosis in 82% (14/17), and obliterative phlebitis in 0%. The abundant IgG4-positive plasma cells were observed in 18% (3/17).

CONCLUSIONS

The IDUS findings were useful for distinction of IgG4-SC from cholangiocarcinoma. Transpapillary biopsy was not useful for direct diagnosis of IgG4-SC even after IgG4 immunostaining, but it did allow distinction of IgG4-SC from cholangiocarcinoma in some cases. IDUS and transpapillary biopsy after endoscopic retrograde cholangiopancreatography can provide further information for precise diagnosis of IgG4-SC.

Japanese clinical guidelines for autoimmune pancreatitis

OBJECTIVES

As the patients with autoimmune pancreatitis (AIP) are increasing in Japan, the practical guideline for managing AIP is required to be established.

METHODS

Three committees (the professional committee for making clinical questions [CQs] and statements by Japanese specialists, the expert panelist committee for rating statements by the modified Delphi method, and the evaluating committee by moderators) were organized. Fifteen specialists for AIP extracted the specific clinical statements from a total of 871 literatures by PubMed search (approximately 1963-2008) and from a secondary database and made the CQs and statements. The expert panelists individually rated these clinical statements using a modified Delphi approach, in which a clinical statement receiving a median score greater than 7 on a 9-point scale from the panel was regarded as valid.

RESULTS

The professional committee made 13, 6, 6, and 11 CQs and statements for the concept and diagnosis, extrapancreatic lesions, differential diagnosis, and treatment, respectively. The expert panelists regarded them as valid after a 2-round modified Delphi approach.

CONCLUSIONS

After evaluation by the moderators, the Japanese clinical guideline for AIP has been established. Further studies for the international guideline are needed after international consensus for diagnosis and treatment.

Utility of 18F-FDG PET/CT for differentiation of autoimmune pancreatitis with atypical pancreatic imaging findings from pancreatic cancer

OBJECTIVE

This study was conducted to evaluate the clinical usefulness of PET/CT in differentiating autoimmune pancreatitis from pancreatic cancer.

MATERIALS AND METHODS

To differentiate autoimmune pancreatitis from pancreatic cancer, we analyzed the cases of 17 patients with autoimmune pancreatitis and atypical pancreatic imaging findings who underwent integrated PET/CT. The PET/CT findings on the 17 patients with autoimmune pancreatitis were compared with those of 151 patients with pancreatic cancer.

RESULTS

Fluorine-18 FDG uptake by the pancreas was found in all patients with autoimmune pancreatitis and in 82% (124/151) of patients with pancreatic cancer. Diffuse uptake by the pancreas was significantly more frequent in patients with autoimmune pancreatitis (53% vs 3%, p < 0.001). FDG uptake by the salivary glands and kidneys was seen only in patients with autoimmune pancreatitis, the former reaching statistical significance (p = 0.003). Follow-up PET/CT after steroid therapy was performed for eight patients with autoimmune pancreatitis. After steroid therapy, none of the patients had intense FDG uptake by the pancreas or extrapancreatic organs.

CONCLUSION

In difficult cases, at PET/CT the presence of diffuse uptake of FDG by the pancreas or concomitant extrapancreatic uptake by the salivary glands can be used to aid in differentiation of autoimmune pancreatitis and pancreatic cancer.

Usefulness of positron emission tomography in the evaluation of distribution and activity of systemic lesions associated with autoimmune pancreatitis

BACKGROUND/AIMS

Autoimmune pancreatitis (AIP) is an IgG4-related systemic disease often accompanied with a variety of lesions outside of the pancreas and is treated with steroid therapy. The aim of this study is to analyze the usefulness of positron emission tomography with (18)F-fluorodeoxyglucose (FDG-PET) in the evaluation of distribution and activity of systemic lesions of AIP during steroid therapy.

METHODS

Eleven cases of AIP had their FDG-PET images evaluated before and 3 months after steroid therapy and another 2 cases only before therapy. AIP activity was determined by the level of serum markers, IgG and IgG4, and compared with findings of PET.

RESULTS

In all 13 cases of AIP, a moderate to intense level of FDG accumulation was recognized in the pancreatic lesion before steroid therapy. Of 13 patients, 11 (84.6%) showed FDG accumulation in the multiple organs, such as mediastinal and other lymph nodes, salivary gland, biliary tract, prostate, and aortic wall. In 11 patients who underwent PET before and after steroid therapy, FDG accumulation was diminished in almost all systemic lesions, with a mean of maximum standardized uptake value (SUV(max)) in the pancreatic lesion from 5.12 to 2.69. Similar to the SUV level, serum IgG and IgG4 were decreased in most of the cases after steroid therapy.

CONCLUSIONS

FDG-PET is an effective modality to evaluate the response of steroid therapy and the distribution and activity of various systemic lesions of AIP.

The clinical and radiological characteristics of focal mass-forming autoimmune pancreatitis: comparison with chronic pancreatitis and pancreatic cancer

OBJECTIVES

We investigated the clinical and radiological features of focal mass-forming autoimmune pancreatitis (FMF AIP) to help physicians avoid performing unnecessary surgery because of an improper diagnosis.

METHODS

We evaluated 23 patients with chronic inflammatory pancreatic masses and who underwent pancreatectomy for presumed pancreatic cancer from April 1995 to December 2005. These patients were distinguished into 8 FMF AIP patients and 15 ordinary chronic pancreatitis patients through a histological review, along with considering the immunoglobulin G4 staining. Twenty-six randomly selected pancreatic cancer patients were also evaluated as a control group.

RESULTS

On the portal venous phase of computed tomography, 6 (85.7%) of 7 FMF AIP patients showed homogeneous enhancement, whereas only 3 chronic pancreatitis patients (25%) and none of the pancreatic cancer patients showed homogeneous enhancement (P < 0.001). None of the FMF AIP patients showed upstream main pancreatic duct dilatation greater than 5 mm or proximal pancreatic atrophy.

CONCLUSIONS

For patients with a pancreatic mass, if their radiological images show homogeneous enhancement on the portal venous phase, the absence of significant upstream main pancreatic duct dilatation greater than 5 mm, and the absence of proximal pancreatic atrophy, then conducting further evaluations should be considered to avoid performing unnecessary surgery.

Autoimmune pancreatitis: an update

Autoimmune pancreatitis (AIP) is the pancreatic manifestation of a systemic fibroinflammatory disorder. It has been recognized as a distinct clinical entity, only recently. Multiple organs, such bile ducts, salivary glands, kidneys and lymph nodes, can be involved either synchronously or metachronously. It is one of the few autoimmune conditions that predominantly affects male subjects in the fifth and sixth decades of life. Obstructive jaundice is the most common presenting symptom but the presentation can be quite nonspecific. There are established diagnostic criteria to diagnose AIP, most of which rely on a combination of clinical presentation, imaging of the pancreas and other organs (by CT scan, MRI and endoscopic retrograde pancreatography), serology, pancreatic histology and response to steroids to make the diagnosis. It is imperative to differentiate AIP from pancreatic cancer owing to the vastly different prognostic and therapeutic implications. AIP responds dramatically to steroid treatment but relapses are common. Relapse of AIP can often be retreated with steroids. As the collective experience with this condition increases, a better understanding of the natural history of this disease is emerging.

Autoimmune pancreatitis and IgG4-associated sclerosing cholangitis

Autoimmune pancreatitis (AIP) is a unique form of chronic pancreatitis characterised by a high serum IgG4 concentration and complications that include various extrapancreatic manifestations, one of which is sclerosing cholangitis. In AIP patients, infiltration of abundant IgG4-positive plasma cells and dense fibrosis are commonly observed in the pancreas and wall of the bile duct and gallbladder. The major symptom at onset of AIP is obstructive jaundice caused by stricture of the bile duct, and this requires differential diagnosis of AIP from pancreato-biliary malignancies and primary sclerosing cholangitis (PSC). Recently, there have been reports of particular cases of sclerosing cholangitis with a high serum IgG4 level and cholangiographic and pathological findings comparable to those observed in AIP patients. Being apparently different from PSC and similar to that in AIP, sclerosing cholangitis with and without AIP shows a clinical response to steroid therapy and thus is designated as 'IgG4-associated sclerosing cholangitis'. The pathogenesis of AIP and IgG4-associated sclerosing cholangitis remains at yet undetermined.

Autoimmune pancreatitis without a response to steroid therapy: a case which met criteria after withdrawal of steroid

Autoimmune pancreatitis (AIP) sometimes forms a pancreatic mass lesion, which is often difficult to distinguish from pancreatobiliary malignancy, however it generally responds to steroid therapy. A 70-year-old man was referred to our institute with the suspected diagnosis of pancreatic cancer due to a mass lesion detected at the pancreatic head. Various images demonstrated an ill-defined mass at the enlarged pancreatic head with focal narrowing of the main pancreatic duct. Serum antinuclear antibody (ANA) was negative (x40 dilution) on the onset. Forceps biopsy from the narrowed pancreaticobiliary duct and fine-needle aspiration biopsy under endoscopic ultrasonography (EUS-FNAB) ruled out pancreatobiliary malignancy. Steroid therapy was started at 40 mg per day but was not effective according to subsequent image analyses. Repeated EUS-FNA from the pancreatic mass was performed but was again negative for carcinoma. Seven months later, under steroid-off condition, still no response was recognized in the clinical image but the titer of serum ANA was increased to be positive (x80), satisfying the criteria of AIP in Japan (2006). Although very rare, this is a case meeting Japanese criteria of AIP after withdrawal of steroid without response to steroid in the clinical images, suggesting the necessity of careful follow-up.

Usefulness of serum IgG4 in the diagnosis and follow up of autoimmune pancreatitis: A systematic literature review and meta-analysis

High circulating serum immunoglobulin G4 (IgG4) levels have been proposed as a marker of autoimmune pancreatitis (AIP). The aim of the present study was to review the data existing in the English literature on the usefulness of the IgG4 serum levels in the diagnosis and follow up of patients with AIP. A total of 159 patients with AIP and 1099 controls were described in seven selected papers reporting the usefulness of serum IgG4 in diagnosing AIP. In total, 304 controls had pancreatic cancer, 96 had autoimmune diseases, and the remaining 699 had other conditions. The summary receiver-operating characteristic curve analysis was carried out by means of Meta-DiSc open-access software. Serum IgG4 showed good accuracy in distinguishing between AIP and the overall controls, pancreatic cancer and other autoimmune diseases (area under the curve [+/- SE]: 0.920 +/- 0.073, 0.914 +/- 0.191, and 0.949 +/- 0.024, respectively). The studies analyzed showed significantly heterogeneous specificity values in each of the three analyses performed. The analysis of the four studies comparing AIP and pancreatic cancers also showed significantly heterogeneous values of sensitivities and odds ratios. Regarding the usefulness of IgG4 as a marker of efficacy of steroid treatment, a decrease in the serum concentrations of IgG4 was found in the four available studies. The serum IgG4 subclass is a good marker of AIP, and its determination should be included in the diagnostic workup of this disease. However, the heterogeneity of the studies published until now means that more studies are necessary in order to better evaluate the true accuracy of IgG4 in discriminating AIP versus other autoimmune diseases.

A case of pancreatic carcinoma with suspected autoimmune pancreatitis

We present a case of pancreatic carcinoma with strongly suspected coexisting autoimmune pancreatitis (AIP). The patient presented with a chief complaint of icterus and weight loss, and was referred to our institution after a pancreatic lesion was found. Blood test showed elevation of serum bilirubin, hepato-biliary enzyme, glucose and tumor markers, and also high levels of serum IgG4 (344 mg/dl, normal 4.8-105 mg/dl) and anti-DNA antibody (14 IU/ml, normal <6.0 IU/ml). Ultrasonography demonstrated an enlarged pancreas with smooth borders and low internal echo density. Enhanced computed tomography (CT) showed a sausage-shaped pancreas without definitive metastasis to the surrounding lymph nodes and liver. Imaging of the pancreatic duct, including endoscopic retrograde pancreatography (ERP) and magnetic resonance cholangiopancreatography (MRCP), showed stenosis of the main pancreatic duct at the pancreatic head as well as a long segment of narrowing at the body and no dilatation at the tail. Tissues from these stenotic sites and open biopsy from pancreatic body showed infiltrating adenocarcinoma and dense fibrosis. To date, only a small number of reports have described pancreatic carcinoma accompanied with AIP. It is important to confirm diagnosis with histology in cases of suspicious autoimmune pancreatitis, even when the clinical images are compatible with AIP.

Differentiating sclerosing cholangitis caused by autoimmune pancreatitis and primary sclerosing cholangitis according to endoscopic duodenal papillary features

BACKGROUND

Differentiating primary sclerosing cholangitis (PSC) and sclerosing cholangitis caused by autoimmune pancreatitis (SC-AIP) is often challenging. Recently, endoscopic findings of the duodenal papilla in cases with AIP or PSC were reported by Unno and Parlak, although the endoscopic differentiation of these 2 conditions has not yet been fully clarified.

OBJECTIVE

Our purpose was to clarify the endoscopic findings of the duodenal papilla in patients with SC-AIP and those with PSC and to determine criteria for the differentiation of these conditions.

DESIGN

Case series.

SETTING

Retrospective.

PATIENTS

Twenty-seven patients with SC-AIP and 12 patients with PSC who had undergone ERCP were identified from our database. We reviewed these records to determine whether the duodenal papillary findings (swollen papilla/normal papilla/small papilla) might be potentially useful for differentiating SC-AIP and PSC. Immunohistopathological findings for the duodenal papilla were also examined by using immunoglobulin G4 (IgG4) among the infiltrating plasma cells.

INTERVENTIONS

ERCP, biopsy specimen taken from duodenal papilla.

MAIN OUTCOME MEASUREMENTS

The presence of a swollen duodenal papilla with IgG4-positive plasma cells was useful for discriminating SC-AIP from with PSC.

RESULTS

A swollen duodenal papilla was observed in 63% (17/27) of the patients with SC-AIP, whereas there was no swelling of the duodenal papilla of the patients with PSC. A small papilla was recognized in 50% (6/12) of the patients with PSC. IgG4-positive plasma cells in the duodenal papilla were significantly detected in the patients with SC-AIP but not in the patients with PSC.

LIMITATION

Single-center study.

CONCLUSIONS

Characteristic duodenal endoscopic papillary features in patients with SC-AIP, such as a swollen duodenal papilla and positive immunostaining for IgG4, might be helpful for discriminating this condition from PSC.

Autoimmune pancreatitis: disease evolution, staging, response assessment, and CT features that predict response to corticosteroid therapy

PURPOSE

To evaluate the evolution of morphologic features of autoimmune pancreatitis (AIP) at computed tomography (CT) and to identify imaging features that can predict AIP response to corticosteroid therapy (CST).

MATERIALS AND METHODS

This HIPAA-compliant retrospective study had institutional review board approval. From among a cohort of 63 patients with AIP, 15 patients (12 men, three women; mean age, 64.7 years; age range, 30-84 years) who underwent sequential CT examinations before treatment were included to assess the evolution of disease by reviewing pancreatic, peripancreatic, and ductal changes. Of these patients, 13 received CST and underwent posttreatment CT; these CT studies were evaluated to determine if there were imaging features that could predict response to CST.

RESULTS

The disease evolved from changes of diffuse (14 of 15 patients) or focal (one of 15 patients) parenchymal swelling, peripancreatic stranding (10 of 15 patients), "halo" (nine of 15 patients), pancreatic duct changes (15 of 15 patients), and distal common bile duct narrowing (12 of 15 patients) to either resolution or development of ductal strictures and/or focal masslike swelling. In 13 patients treated with CST, favorable response to treatment was seen in those with diffuse pancreatic and peripancreatic changes. Suboptimal response was seen in patients with ductal stricture formation (two of 13 patients) and in those in whom focal masslike swellings persisted after resolution of diffuse changes (seven of 13 patients).

CONCLUSION

CT features like diffuse swelling and halo respond favorably to CST and likely reflect an early inflammatory phase, whereas features like ductal strictures and focal masslike swelling are predictive of a suboptimal response and symbolize a late stage with predominance of fibrosis.

[Bile duct involvement in autoimmune pancreatitis: classification and treatment]

Autoimmune pancreatitis is a rare disease characterized by inflammation of the pancreatic parenchyma, irregular narrowing of the pancreatic duct, periductal lymphoplasmacytic infiltration and fibrosis at histological examination, the presence of autoantibodies and hypergammaglobulinemia, as well as the possible association of cholangitis and other autoimmune diseases. There is a favorable response to steroid therapy. We report the case of a patient with autoimmune pancreatitis with bile duct involvement and peripheral eosinophilia, requiring long-term immunosuppressant treatment. The diagnosis of a diffuse form of AIP was made without direct histological evidence and based on indirect imaging, clinical and laboratory findings in an autoimmune context. The histological and imaging studies of bile duct involvement and the favourable response to steroids were additional arguments.

Review of 67 patients with autoimmune pancreatitis in Korea: a multicenter nationwide study

OBJECTIVES

The ideal diagnostic criteria of autoimmune pancreatitis (AIP) are still challenging. Therefore, we investigated the clinical features of AIP in Korea and assessed the clinical use of new Korean diagnostic criteria.

METHODS

We reviewed 67 patients with AIP enrolled in 16 hospitals via a multicenter study. The diagnosis was confirmed according to the Korean diagnostic criteria that included pancreatic imaging, laboratory findings, histopathology, and response to steroid.

RESULTS

Mean age of the patients was 56 years, and 73% were men. Obstructive jaundice (52%) was the most common symptom, and 14 patients (21%) had other organ involvement. Fifty-four patients (81%) revealed diffuse swelling of the pancreas. Either immunoglobulin (Ig)G or IgG4 was elevated in 76%. According to the Korean criteria, 65 patients had definite diagnostic criteria, and 2 patients had probable criteria. Fifteen patients were fulfilled with image, serological, and histopathologic criteria, and 4 patients could be diagnosed with image and steroid responsiveness. Ten patients experienced recurrent attacks of AIP during the mean 20-month follow-up.

CONCLUSIONS

Among 67 cases of AIP, either IgG or IgG4 was elevated in 76% of patients, and 14 patients (21%) had other organ involvement. New Korean diagnostic criteria are useful for diagnosis of AIP.

Diagnostic ascertainment of suspicious pancreatic mass: a threshold analysis

BACKGROUND & AIMS

It is frequently difficult to differentiate between a benign and malignant pancreatic mass. The aim of this study was to assess the parameters that affect the decision to perform surgery on a suspicious pancreatic head lesion.

METHODS

A cost-benefit analysis, using decision tree and threshold analysis, accumulates costs and quality-adjusted life years in patients undergoing pancreaticoduodenectomy or expectant management. The threshold value is defined as the diagnostic probability for pancreatic cancer when the cost-benefit relationships of pancreaticoduodenectomy or expectant management are equal.

RESULTS

For a localized pancreatic head lesion, the threshold probability of cancer is 43%. Any higher probability of pancreatic cancer makes pancreaticoduodenectomy the preferred treatment option. Within a range of $20,000 to $80,000 spent on surgery, the threshold in favor of Whipple procedure remains relatively low at 40% to 65%. A reduced quality of life after surgery weighs against surgery and raises its threshold. Varying quality of life between 100% and 80% changes the threshold between 31% and 67%. The threshold also is increased in younger patients because of the potentially more dire consequences of unnecessary surgery in instances of long life expectancy.

CONCLUSIONS

Even if diagnostic certainty cannot be achieved, it frequently is beneficial to perform surgery despite the risk of subjecting the occasional patient with benign pancreatic head lesion to an unnecessary pancreaticoduodenectomy.

Strategy for differentiating autoimmune pancreatitis from pancreatic cancer

OBJECTIVES

It is of utmost importance that autoimmune pancreatitis (AIP) be differentiated from pancreatic cancer (PC) because some AIP cases undergo unnecessary laparotomy or pancreatic resection on suspicion of PC. This study aimed to develop an appropriate strategy for differentiating between AIP and PC.

METHODS

Clinical, serological, and radiological features of 17 AIP patients forming a masslike lesion on pancreas head and 70 patients with pancreatic head cancer were compared.

RESULTS

Numerous findings can be used to distinguish between AIP and PC, and the following are more likely in AIP: fluctuating jaundice; elevated serum IgG4 levels; delayed enhancement of the enlarged pancreas and a capsule-like low-density rim on computed tomography; long or skipped narrowed portion with side branches of the main pancreatic duct without upstream dilatation on endoscopic retrograde pancreatography, extrapancreatic lesions, such as stenosis of the intrahepatic bile duct, salivary gland swelling, and retroperitoneal mass; and responsiveness to steroid therapy.

CONCLUSIONS

In elderly male patients presenting with obstructive jaundice and a pancreatic mass, AIP should be considered in the differential diagnosis. Based on a combination of clinical, serological, and radiological findings, AIP can be differentiated from PC. An algorithm for management of patients with a masslike lesion on pancreas head is presented.

Chronic pancreatitis

PURPOSE OF REVIEW

As in previous reviews in this journal, this review is focused on the most important new observations in chronic pancreatitis made in the last year.

RECENT FINDINGS

Important observations included the search for biomarkers and alternative methods for the detection of early chronic pancreatitis; stellate cell activation and their role in fibrogenesis; the natural history of chronic pancreatitis; reports outlining the complexity in diagnosis of autoimmune pancreatitis; emerging roles of endoscopic ultrasound and magnetic resonance cholangiopancreatography in chronic pancreatitis diagnosis; a better understanding of neurobiology of chronic pancreatitis pain; and the potential role of surgery as first-line therapy in advanced chronic pancreatitis.

SUMMARY

In 2007, major advances were made in our understanding of central processing in chronic pancreatitis pain. New techniques are being utilized in search of a better means to diagnose early chronic pancreatitis. Important prospective studies are emerging, which compare endoscopic and surgical interventions. Furthermore, the complexities of diagnosing autoimmune pancreatitis are being recognized. Overall, the future is promising as advances in genomic and proteomic techniques are applied to improve our understanding of chronic pancreatitis.

Autoimmune pancreatitis

PURPOSE OF REVIEW

Autoimmune pancreatitis (AIP) is an increasingly recognized clinical condition. Our objective is to provide a concise review of the advances in the past year in our understanding of AIP.

RECENT FINDINGS

In a hospital survey from Japan, the prevalence of AIP was estimated at 0.82 per 100,000 individuals. The pathogenesis of AIP remains unclear but a recent report noted that T helper type 2 and T regulatory cells predominantly mediate the immune reaction in AIP. Genetic associations that may predispose to relapse of AIP were reported. Multiple case series further described the clinical profile of AIP and its extrapancreatic manifestations. A large series on immunoglobulin G4 (IgG4)-associated cholangitis noted that patients with IgG4-associated cholangitis presented with obstructive jaundice and had increased serum IgG4 levels and IgG4-positive cells in bile duct biopsy specimens. Tissue IgG4 staining is likely to be a useful adjunct to serological diagnosis. AIP is steroid-responsive but maintaining remission continues to remain challenging. Presently low-dose steroids or immunomodulators are being used but efficacy of these medications remains to be determined.

SUMMARY

There has been significant progress in understanding the clinical profile of AIP but knowledge of pathogenesis remains limited. Treatment practices vary widely and management of refractory disease continues to be challenging.

A new diagnostic endoscopic tool for autoimmune pancreatitis

BACKGROUND

Autoimmune pancreatitis (AIP) is a type of pancreatitis that is presumed to have an autoimmune etiology, and is currently diagnosed based on a combination of clinical, laboratory, and imaging studies. Although it is of utmost importance that AIP be differentiated from pancreatic cancer, AIP is sometimes difficult to differentiate from locally advanced pancreatic cancer.

OBJECTIVE

To find a useful new method to diagnose AIP.

DESIGN

Prospective study from June 2004 to September 2007.

SETTING

Single public hospital.

PATIENTS

Ten AIP patients, 10 patients with pancreatic cancer, and 10 patients with papillitis.

INTERVENTIONS

Immunoglobulin (Ig)G4-immunostaining of biopsy specimens obtained from the major duodenal papilla.

MAIN OUTCOME MEASUREMENTS

Number of immunohistochemically identified cells per high-power field (HPF) in each specimen were counted.

RESULTS

Significant infiltration of IgG4-positive plasma cells (> or = 10/HPF) was observed in the major duodenal papilla of all 8 AIP patients with pancreatic head involvement. Moderate infiltration of IgG4-positive plasma cells (4-9/HPF) was detected in 1 patient with pancreatic head cancer, but there were rare (< or = 3/HPF) IgG4-positive plasma cells infiltrating the major duodenal papilla in 2 AIP patients who only had pancreatic body and/or tail involvement, 9 patients with pancreatic cancer, and 10 patients with papillitis. In the 3 AIP patients in whom biopsy specimens were retaken after steroid therapy, the number of IgG4-positive plasma cells decreased from significant to moderate in 2 patients and to < or = 3/HPF in 1 patient.

LIMITATIONS

Small sample size. Endoscopists were not blinded to clinical information.

CONCLUSIONS

IgG4 immunostaining of biopsy specimens obtained from the major duodenal papilla may be useful for supporting a diagnosis of AIP with pancreatic head involvement.

Autoimmune pancreatitis: with special reference to a localized variant

In 2006, the Japan Pancreas Society revised the diagnostic criteria for autoimmune pancreatitis (AIP) so as to more clearly define its morphological, pathological, and immunological features, as follows: (1) diffuse or segmental narrowing of the main pancreatic duct with an irregular wall and diffuse or localized enlargement of the pancreas recognized by imaging studies; (2) high serum gamma globulin, IgG, or IgG4 levels, or the presence of autoantibodies; and (3) marked interlobular fibrosis and prominent infiltration of lymphocytes and plasma cells in the periductal area, occasionally with lymphoid follicles in the pancreas. Establishing a diagnosis of AIP has become easier with knowledge of its immunological abnormalities, including serum IgG4 levels. However, the localized form of AIP sometimes mimics pancreatic cancer. The rate of focal mass formation in patients with AIP is reportedly 24%-43%; however, there have been few reports on the histological findings of localized AIP, in contrast to mass-forming pancreatitis (MFP). Our review of patients who had undergone resection due to a preoperative diagnosis of MFP with possible cancer revealed 72% to be patients with localized AIP. For the discrimination of these conditions, it is important to recognize the characteristic ultrasonographic findings of AIP, i.e., (1) diffuse or localized enlargement and hypoechogenicity of the pancreas; (2) rarity of calcification, cystic lesions, and peripancreatic fluid collection; (3) thickened layer structure of the bile duct wall; (4) iso/hypervascularity in the swollen portion of the pancreas; (5) attenuation of pancreatic swelling and bile duct wall thickening after steroid therapy; and (6) multiple hypoechoic masses in various organs, including the pancreas. Contrast-enhanced endoscopic ultrasonography is potentially a useful tool in the differential diagnosis and for assessment of the efficacy of steroid therapy by enabling evaluation of the vascularity of the lesions. Along with the presence of IgG4-positive plasma cells, verification of obliterative phlebitis is highly specific for the histological diagnosis of AIP.

Isolated Lymphoplasmacytic Sclerosing Pancreatitis Involving the Pancreatic Tail

We present an interesting case of a 62-year-old woman with a 3-month history of vague, left-sided abdominal pain. CT imaging revealed a hypodense lesion in the tail of the pancreas. The patient had no history of pancreatitis or autoimmune diseases. Laboratory testing revealed a normal CA19-9 (33 U/mL) and an elevated IgG4 (133 mg/dL). Due to concerns of pancreatic malignancy, she underwent operation. We found a dense, inflammatory mass in the tail of the pancreas, which was removed via an open distal pancreatectomy with splenectomy. Histologic analysis revealed a pancreas with sclerotic ducts and surrounding lymphoplasmacytic inflammation most consistent with lymphoplasmacytic sclerosing pancreatitis (LPSP). LPSP, also termed autoimmune pancreatitis, is a benign disease of the pancreas, which can mimic pancreatic adenocarcinoma. It is the most common benign finding diagnosed on pathology after pancreatic resection for presumed malignancy. LPSP most commonly involves the head and, more uncommonly, the tail of the pancreas. It can be successfully treated with steroids obviating the need for resection. IgG4 levels may assist in recognition of this disease. As our experience with utilization of IgG4 testing and knowledge of the systemic nature of LPSP increase, patients with this disease may be spared unnecessary resection.

Diagnosis and management of autoimmune pancreatitis: Experience from China

AIM: To determine the clinical, radiographic and pathologic characteristics, diagnostic and treatment modalities in patients with autoimmune pancreatitis (AIP).

METHODS: In this retrospective study, the data of patients with diagnosed chronic pancreatitis (CP) between 1995 and 2006 in Chinese PLA General Hospital were included to screen for the cases with AIP, according to the following diagnostic criteria: (1) diagnostic histopathologic features, and abound IgG4-positive plasma cells on pancreatic tissues; (2) characteristic imaging on computed tomography and pancreatography, together with increased serum IgG, γ-globulin levels or presence of autoantibodies; (3) response to steroid therapy. The clinical, radiographic and pathologic characteristics, diagnostic and treatment modalities, and outcome of AIP cases were reviewed.

RESULTS: Twenty-five (22 male, 3 female; mean age 54 years, 36-76 years) out of 510 CP patients were diagnosed as AIP, which accounted for 49% (21/43) of CP population undergoing surgical treatment in the same period. The main clinical manifestations included intermittent or progressive jaundice in 18 cases (72%), abdominal pain in 11 (44%), weight loss in 10 (40%), and 3 cases had no symptoms. The imaging features consisted of pancreatic enlargement, especially in the head of pancreas (18 cases), strictures of main pancreatic duct and intrapancreatic bile duct. Massive lymphocytes and plasma cells infiltration in pancreatic tissues were showed on pathology, as well as parenchymal fibrosis. Twenty-three patients were misdiagnosed as pancreaticobiliary malignancy, and 21 patients underwent exploratory laparotomy, the remaining 4 patients dramatically responded to steroid therapy. No pancreatic cancer occurred during a mean 46-mo follow-up period.

CONCLUSION: AIP patients always are subjected to mistaken diagnosis of pancreatic cancer and an unnecessary surgical exploration, due to its similarity in clinical features with pancreatic cancer. The differential diagnosis with high index of suspicion of AIP would improve the diagnostic accuracy for AIP.

Autoimmune pancreatitis associated with hemorrhagic pseudocysts: a case report and literature review

Autoimmune pancreatitis (AIP) is a new category of pancreatic diseases. AIP associated with pseudocysts is rare; only 8 cases have been reported in the literature. A 63-year-old man was admitted to our department because of upper left abdominal pain and back pain. Various imaging studies demonstrated swelling of the tail of the pancreas with hemorrhagic pseudocysts. The patient underwent a surgical operation. A pancreatogram of the specimen revealed total occlusion of the main pancreatic duct in the tail of the pancreas. Histopathological examination revealed that it was AIP with hemorrhagic pseudocysts.

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.

Pancreatic cancer associated with autoimmune pancreatitis in remission

In January 2007, an 80-year-old man was admitted to our hospital for treatment of a pancreatic tumor. He had been diagnosed with autoimmune pancreatitis (AIP) in December 2003 for which steroid therapy had induced remission. In November 2006, tumor marker levels rapidly increased, and the patient was suspected of having pancreatic cancer based on imaging studies. The diagnosis was later confirmed by endoscopic ultrasound-guided fine-needle aspiration biopsy. Distinguishing AIP from pancreatic cancer is crucial; however, few previous reports have described any cases of pancreatic cancer associated with AIP. While several reports have speculated on the prognosis of AIP, natural courses of the disease remain uncertain. This report emphasizes that AIP can coexist with cancer.

Chronic pancreatitis

PURPOSE OF REVIEW

As in previous reviews in this journal, this review is focused on the most important new observations in chronic pancreatitis made in the past year and the beginning of this year.

RECENT FINDINGS

Important observations include the following: first, the natural history and course of chronic pancreatitis; second, that smoking enhances the risk of chronic pancreatitis; third, possible new function tests in combination with imaging procedures; fourth, the superiority of surgery compared with endotherapy for long-term pain relief; fifth, new insights in autoimmune pancreatitis.

SUMMARY

All in all, little progress has recently been made in the field of diagnosis and therapy of chronic pancreatitis. There are some studies in the field of endotherapy and autoimmune pancreatitis that are promising however.

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.

Systemic extrapancreatic lesions associated with autoimmune pancreatitis

Autoimmune pancreatitis (AIP) is frequently associated with sclerosing cholangitis (SC). SC with AIP has a cholangiographic appearance that is often confused with primary sclerosing cholangitis (PSC) but only the former responds well to corticosteroid therapy. Detailed study of cholangiographic findings allows discrimination of SC with AIP from PSC. Band-like strictures, a beaded or pruned-tree appearance, and diverticulum-like outpouching were significantly more frequently observed in cases of PSC. In contrast, segmental strictures, dilation after confluent stricture, and strictures of the lower common bile duct were significantly more common in SC with AIP. The other systemic extrapancreatic lesions associated with AIP found in the literature were Sjögren's syndrome, ulcerative colitis, retroperitoneal fibrosis, sialadenitis, thyroiditis, and idiopathic thrombocytopenic purpura. In a comparison of the clinical course and laboratory data of our cases, gamma-globulin, IgG, and IgG4 levels were significantly higher in patients with AIP with systemic extrapancreatic lesions than those without them. In our immunohistochemical study, marked infiltration of IgG4+ plasma cells was frequently observed in the pancreas, liver, bile duct, and salivary glands of the AIP patients examined. In contrast, the degree of infiltration of IgG4+ plasma cells around the bile duct in the portal areas and the extrahepatic bile duct with PSC was significantly lower than with AIP. These results also suggest that AIP is a disease state clearly different from PSC. In addition, the normal epithelia of the pancreatic ducts, bile ducts, gallbladder, and salivary gland ducts reacting with the patients' sera was detectable by the anti-IgG4 antibody. Therefore, AIP may also affect extrapancreatic organs, and the sera of AIP patients may contain an IgG4 autoantibody to various organs.

Autoimmune pancreatitis with retroperitoneal fibrosis which responded to steroid therapy but was complicated with refractory renal dysfunction

A 58-year-old male had been diagnosed as having autoimmune pancreatitis (AIP) from the results of serological examinations and image findings. He was treated with prednisolone (PSL) for 3.5 months. Fifteen months later, follow-up CT revealed the main pancreatic duct (MPD) dilatation in the pancreas body to tail and right hydronephrosis caused by complicated retroperitoneal mass. We diagnosed him as having recurrent AIP with retroperitoneal fibrosis, and restarted PSL treatment. After one month, Examinations indicated amelioration of the MPD dilatation and right hydronephrosis, but not the right renal failure. This case indicates the importance of maintenance of PSL treatment.