Clinical diagnostic criteria of autoimmune pancreatitis: revised proposal

Diagnosis of IgG4-related sclerosing cholangitis

IgG4-related sclerosing cholangitis (IgG4-SC) is often associated with autoimmune pancreatitis. However, the diffuse cholangiographic abnormalities observed in IgG4-SC may resemble those observed in primary sclerosing cholangitis (PSC), and the presence of segmental stenosis suggests cholangiocarcinoma (CC). IgG4-SC responds well to steroid therapy, whereas PSC is only effectively treated with liver transplantation and CC requires surgical intervention. Since IgG4-SC was first described, it has become a third distinct clinical entity of sclerosing cholangitis. The aim of this review was to introduce the diagnostic methods for IgG4-SC. IgG4-SC should be carefully diagnosed based on a combination of characteristic clinical, serological, morphological, and histopathological features after cholangiographic classification and targeting of a disease for differential diagnosis. When intrapancreatic stenosis is detected, pancreatic cancer or CC should be ruled out. If multiple intrahepatic stenoses are evident, PSC should be distinguished on the basis of cholangiographic findings and liver biopsy with IgG4 immunostaining. Associated inflammatory bowel disease is suggestive of PSC. If stenosis is demonstrated in the hepatic hilar region, CC should be discriminated by ultrasonography, intraductal ultrasonography, bile duct biopsy, and a higher cutoff serum IgG4 level of 182 mg/dL.

International Consensus Diagnostic Criteria for Autoimmune Pancreatitis and Its Japanese Amendment Have Improved Diagnostic Ability over Existing Criteria

Objectives. The recent International Consensus Diagnostic Criteria (ICDC) for autoimmune pancreatitis (AIP) and its Japanese amendment developed by the Japanese Pancreas Society (JPS 2011) may have overcome the drawbacks of earlier criteria and achieved a higher diagnostic ability for AIP. The aim of the present study is to evaluate this possibility and identify the underlying causes of this change. Methods. We compared the diagnostic abilities of the ICDC and JPS 2011 with those of the Japanese diagnostic criteria 2006 (JPS 2006), Korean diagnostic criteria (Korean), Asian diagnostic criteria (Asian), and HISORt diagnostic criteria in 110 patients with AIP and 31 patients with malignant pancreatic cancer. Results. The ICDC achieved the highest diagnostic ability in terms of accuracy (95.0%), followed by JPS 2011 (92.9%), Korean (92.2%), HISORt (88.7%), Asian (87.2%), and JPS 2006 (85.1%). Nearly all criteria systems exhibited a high specificity of 100%, indicating that the enhanced diagnostic ability of the ICDC and JPS 2011 likely stemmed from increased sensitivity brought about by inclusion of diagnostic items requiring no endoscopic retrograde pancreatography. The diagnostic ability of JPS 2011 was nearly equivalent to that of the ICDC. Conclusions. The ICDC and JPS 2011 have improved diagnostic ability as compared with earlier criteria sets because of an increase in sensitivity.

Clinical evaluation of international consensus diagnostic criteria for type 1 autoimmune pancreatitis in comparison with Japanese diagnostic criteria 2011

OBJECTIVES

The objective of this study was to evaluate the International Consensus Diagnostic Criteria (ICDC) for type 1 autoimmune pancreatitis (AIP) in comparison with the Japanese criteria 2011 (JPS2011).

METHODS

We retrospectively investigated the usefulness of ICDC in comparison with JPS2011 in 64 patients with AIP and 90 patients with pancreatic cancer.

RESULTS

The sensitivity and specificity of ICDC for AIP were 98.4% (63/64) and 100% (90/90), respectively. The sensitivities and specificities of ductal imaging, serology, other organ involvement, and pancreatic histology were 74.1%, 89.1%, 53.1%, and 26.1% and 94.7%, 94.5%, 100%, and 100%, respectively. On the other hand, the sensitivities and specificities of JPS2011 for AIP were 84.4% (54/64) and 100% (90/90), respectively. The condition of all the 10 patients who were deniable or possible under the JPS2011 could be diagnosed as definitive AIP under the ICDC. The sensitivities and specificities of Japanese criteria 2006, Asian Diagnostic Criteria, and HISORt criteria were 80.6%, 84.4%, and 92.2% and 95.8%, 87.8%, and 100%, respectively.

CONCLUSIONS

The sensitivity and specificity of ICDC are higher than those of previous criteria. The JPS2011 is easy to handle for general practice, and specificity is very high. However, the sensitivity of JPS2011 is lower than that of ICDC, and improvement of sensitivity is to be hoped in the future.

Capability and limitations of recent diagnostic criteria for autoimmune pancreatitis

Because a diagnostic serological marker is unavailable, autoimmune pancreatitis (AIP) is diagnosed based on unique features. The diagnostic capabilities and potential limitations of four sets of diagnostic criteria for AIP (Japanese diagnostic criteria 2006 and 2011, Asian diagnostic criteria, and international consensus diagnostic criteria (ICDC)) were compared among 85 patients who were diagnosed AIP according to at least one of the four sets. AIP was diagnosed in 87%, 95%, 95%, and 95% of the patients according to the Japanese 2006, Asian, ICDC, and Japanese 2011 criteria, respectively. The ICDC can diagnose types 1 and 2 AIP independently and show high sensitivity for diagnosis of AIP. However, as the ICDC are rather complex, diagnostic criteria for AIP should perhaps be revised and tailored to each country based on the ICDC.

Clinical strategies for differentiating autoimmune pancreatitis from pancreatic malignancy to avoid unnecessary surgical resection

OBJECTIVE

The study aimed to determine a practical strategy for differentiating between autoimmune pancreatitis (AIP) and pancreatic malignancy in order to avoid unnecessary surgical resection.

METHODS

Altogether, 19 patients with AIP or other pancreatic diseases underwent routine examinations including liver function test and carbohydrate antigen 19-9, computed tomography and/or magnetic resonance imaging. Serum immunoglobulin G (IgG) and/or IgG4 was determined in patients with clinically suspected or pathologically proven AIP. Patients with suspected AIP either received diagnostic steroid therapy or laparotomy (if malignant tumors could not be excluded). Surgery was not performed in patients with a definite diagnosis of AIP by fast intraoperative frozen biopsy. Those with confirmed AIP received steroid treatment.

RESULTS

In total, 15 cases were finally confirmed as AIP with eight diagnosed preoperatively, five confirmed by surgical pathology (preoperatively misdiagnosed) and two by intraoperative biopsy. Of these 15 patients with AIP and one without AIP, 14 had elevated serum γ-globulin levels. It was proven by subsequent antibody tests that serum IgG or IgG4 were simultaneously increased.

CONCLUSIONS

Elevated serum γ-globulin level can be used as a preoperative sentinel indicator for differentiating between IgG4-related AIP and pancreatic malignancy. Serum IgG or IgG4 tests should be further performed in those with elevated serum γ-globulin level, which helps to identify AIP in order to avoid unnecessary operation.

Factors affecting the yield of endoscopic transpapillary bile duct biopsy for the diagnosis of pancreatic head cancer

BACKGROUND

Transpapillary biliary biopsy (TBB) is a simple endoscopic technique that can be performed during an initial biliary drainage session. This procedure has the potential to reduce the load of another tissue sampling in cases of pancreatic head cancer (PHC) with biliary stricture. The aim of this study is to identify factors associated with a positive outcome using TBB for PHC.

METHODS

In total, 130 cases that underwent TBB for investigation of distal biliary stricture were included [62 cases of PHC, 36 cases of distal biliary cancer (DBC), and 32 cases of benign biliary stricture (BBS)]. Factors affecting the diagnostic efficiency of TBB were determined using univariate and multivariate logistic analyses.

RESULTS

Cancer tissue was obtained in 31 cases (50%) of PHC and 33 cases (91.7%) of DBC. Multivariable analysis showed that ≧10 mg/dl of serum bilirubin level (odds ratio [OR]: 5.58; 95% confidence interval [CI]: 1.29-28.20; P = 0.021) and ≧3 tissue samplings (OR: 3.59; 95% CI: 1.02-14.27, P = 0.046) were independent factors affecting cancer-positive rate in cases of PHC. In >90% of resected cases of PHC, cancer involved the left side of the biliary mucosa and the range of cancer invasion (≧2/3 of circumference of biliary mucosa) was also a significant factor (P = 0.001).

CONCLUSIONS

PHC showing high level of serum bilirubin (>10 mg/dl) and high circumferential proportion of bile duct invasion (>2/3 judging from MDCT) is a good indication for biliary biopsy. Targeting the left-side wall and ≧3 tissue samplings will lead to the higher sensitivity.

Recent advances in the diagnosis and management of autoimmune pancreatitis: similarities and differences in Japan and Korea

Two subtypes (types 1 and 2) of autoimmune pancreatitis (AIP) are currently recognized. Type 1 AIP is related to immunoglobulin G4 (lymphoplasmacytic sclerosing pancreatitis), and type 2 AIP is characterized by neutrophilic infiltration into the epithelium of the pancreatic duct (idiopathic duct-centric pancreatitis). Although type 2 AIP is sometimes observed in the United States and Europe, most cases of AIP in Japan and Korea are type 1. The international consensus diagnostic criteria for AIP were created to be applicable worldwide and to distinguish between the two types of AIP. AIP is diagnosed based on the presence of at least one of the five cardinal features (i.e., imaging, serology, other organ involvement, histology, and response to steroid therapy). Oral steroids are the standard therapy for AIP, but immunomodulatory drugs or rituximab have been successfully used for patients with relapsed AIP in the United States and Europe. Generally, the clinical manifestations and demography of AIP are similar between Japan and Korea. However, there are differences in some aspects of the disease, including the proportion of other organ involvement, the prevalence of type 2 AIP, diagnostic criteria and maintenance therapy between the two countries.

Progressive multi-organ expression of immunoglobulin G4-related disease: A case report

A 63-year-old Caucasian man presented with a cholestatic syndrome, renal failure and arthralgias. A laboratory examination revealed high immunoglobulin G (IgG) and IgG4 levels (5.95 g/L; normal range: 0.08-1.4 g/L), pointing to a diagnosis of systemic IgG4-related disease, with definite radiological evidence of biliary and pancreatic expression, and plausible renal, articular, salivary and lacrimal glands involvement. Due to the rarity of the condition, there are currently no random control trials to point to the optimal therapeutic approach. The patient has been on steroid therapy with the subsequent introduction of azathioprine, with a complete resolution of all symptoms, a rapid reduction to normalization of all blood tests, and a complete regression of the radiological picture. Our experience underlines the complexity of IgG4-related disease and its variable and sometimes progressive presentation, while pointing out the need for a careful and complete assessment for possible multi-organ involvement.

Focal autoimmune pancreatitis: Radiological characteristics help to distinguish from pancreatic cancer

AIM: To identify the radiological characteristics of focal autoimmune pancreatitis (f-AIP) useful for differentiation from pancreatic cancer (PC).

METHODS: Magnetic resonance imaging (MRI) and triple-phase computed tomography (CT) scans of 79 patients (19 with f-AIP, 30 with PC, and 30 with a normal pancreas) were evaluated retrospectively. A radiologist measured the CT attenuation of the pancreatic parenchyma, the f-AIP and PC lesions in triple phases. The mean CT attenuation values of the f-AIP lesions were compared with those of PC, and the mean CT attenuation values of pancreatic parenchyma in the three groups were compared. The diagnostic performance of CT attenuation changes from arterial phase to hepatic phase in the differentiation between f-AIP and PC was evaluated using receiver operating characteristic (ROC) curve analysis. We also investigated the incidence of previously reported radiological findings for differentiation between f-AIP and PC.

RESULTS: The mean CT attenuation values of f-AIP lesions in enhanced phases were significantly higher than those of PC (arterial phase: 60 ± 7 vs 48 ± 10, P < 0.05; pancreatic phase: 85 ± 6 vs 63 ± 15, P < 0.05; hepatic phase: 95 ± 7 vs 63 ± 13, P < 0.05). The mean CT attenuation values of f-AIP lesions were significantly lower those of uninvolved pancreas and normal pancreas in the arterial and pancreatic phase of CT (P < 0.001, P < 0.001), with no significant difference at the hepatic phase or unenhanced scanning (P = 0.4, P = 0.1). When the attenuation value increase was equal or more than 28 HU this was considered diagnostic for f-AIP, and a sensitivity of 87.5%, specificity of 100% and an area under the ROC curve of 0.974 (95%CI: 0.928-1.021) were achieved. Five findings were more frequently observed in f-AIP patients: (1) sausage-shaped enlargement; (2) delayed homogeneous enhancement; (3) hypoattenuating capsule-like rim; (4) irregular narrowing of the main pancreatic duct (MPD) and/or stricture of the common bile duct (CBD); and (5) MPD upstream dilation ≤ 5 mm.

CONCLUSION: Analysis of a combination of CT and MRI findings could improve the diagnostic accuracy of differentiating f-AIP from PC.

A solid pancreatic mass: tumour or inflammation?

The prognosis for pancreatic cancer is poor, and early diagnosis is essential for surgical management. By comparison with its classic form, the presence of acute or chronic inflammatory signs will hinder its detection and delay its diagnosis. The atypical forms of acute pancreatitis need to be known in order to detect patients who require additional morphological investigations to search for an underlying tumour. In contrast, pseudotumoral forms of inflammation (chronic pancreatitis, cystic dystrophy in heterotopic pancreas, autoimmune pancreatitis) may simulate a cancer, and make up 5-10% of the surgical procedures for suspected cancer. Faced with these pseudotumoral masses, interpretation relies on various differentiating signs and advances in imaging.

18-Fluorodeoxyglucose positron emission tomography does not aid in diagnosis of pancreatic ductal adenocarcinoma

BACKGROUND & AIMS

There are no accurate and reliable tools for diagnosis of early stage pancreatic ductal adenocarcinoma (PDA) or small metastatic lesions. It is also a challenge to differentiate PDA from focal mass-forming pancreatitis (FMP). There is controversy regarding the efficacy of 18-fluorodeoxyglucose positron-emission tomography (FDG-PET) in the diagnosis of PDA. We investigated whether FDG-PET provides information that, combined with data from other imaging techniques, can aid in decision making for patients with suspected PDA.

METHODS

We performed a retrospective analysis of data collected from 232 consecutive patients with suspected PDA at Kobe University Hospital from January 2006 through June 2012. All patients underwent a diagnostic imaging protocol that included multidetector row computed tomography, superparamagnetic iron oxide-enhanced magnetic resonance imaging, and FDG-PET. Based on endoscopic ultrasonography, fine-needle aspiration biopsy, or endoscopic retrograde cholangiopancreatography analyses, 218 patients had PDA (89 underwent resection and 129 did not) and 14 patients had FMP (8 had focal mass-forming chronic pancreatitis and 6 had focal mass-forming autoimmune pancreatitis).

RESULTS

FDG-PET detected 50% of stages 0 and I, 91.9% of stage II, 100% of stage III, and 96.8% of stage IV tumors. Detection was affected significantly by tumor size (P = .024) and T stage (P = .023) in resected tumors. Multidetector row computed tomography detected significantly more liver metastases than FDG-PET. Few para-aortic lymph node or peritoneal metastases were detected by FDG-PET. FDG-PET correctly identified 11 of the 14 patients with FMP (5 of 8 with focal mass-forming chronic pancreatitis and 6 of 6 with focal mass-forming autoimmune pancreatitis).

CONCLUSIONS

FDG-PET is not effective in detecting early stage PDA and small metastases, or in differentiating PDA from FMP. Combining FDG-PET with current diagnostic techniques for PDA did not provide any decisive information, therefore it should not be included in this analysis.

The clinical course of patients with IgG4-related kidney disease

Long-term follow-up for IgG4-related kidney disease, including relapse information, is sparse. To gather data on this we retrospectively examined the clinical course of 43 patients with IgG4-related kidney disease, in which most patients were treated with, and maintained on, corticosteroids. One month after the start of treatment, most of the abnormal serology and radiology parameters had improved. In 34 of the steroid-treated patients whose follow-up period was more than 12 months (median 34 months), excluding one hemodialysis patient, the estimated glomerular filtration rate (eGFR) before treatment was over 60 ml/min in 14 patients (group A) and under 60 ml/min in 20 patients (group B). In group A, there was no difference between the eGFR before therapy and at the last review. In group B, the mean eGFR before treatment (34.1 ml/min) was significantly improved after 1 month (45.0 ml/min), and renal function was maintained at a similar level through last follow-up. Among 24 evaluated patients at the last review, however, renal atrophy had developed in 2 of 9 in group A and in 9 of 15 in group B. Relapse of IgG4-related lesions occurred in 8 of 40 treated patients. Thus, the response of IgG4-related kidney disease to corticosteroids is rapid, not total, and the recovery of renal function persists for a relatively long time under low-dose maintenance. A large-scale prospective study to formulate more useful treatment strategies is necessary.

IgG4-related diseases

Immunoglobulin G4 (IgG4)-related disease (IgG4-RD) is a fascinating condition recognised as a systemic disease in 2003 [1,2]. The first link between autoimmunity affecting the pancreas, elevated serum IgG4 concentrations and large numbers of IgG4-positive plasma cells in pancreatic tissue was described only 2 years earlier [3]. Since then, many diseases that have long been viewed organ-specific are now considered within the spectrum of IgG4-RD. Practically any organ can be affected, having in common a key pathological feature consisting in dense lymphocyte and plasma cell infiltrate rich in IgG4-positive plasma cells, storiform fibrosis and often an elevated serum IgG4 concentration. While good clinical response to steroid therapy is observed, immunosuppressive or B-cell depleting therapy can be required. It is important to distinguish the IgG4-RD from traditional organ-specific autoimmune disease to guide therapy.

Autoimmune pancreatitis: current concepts

Autoimmune pancreatitis (AIP) is a distinct type of chronic pancreatitis with unique clinical, pathological, serological, and imaging features. AIP usually presents with obstructive jaundice. Imaging studies often reveal enlargement of the pancreas with a pancreatic mass and strictures of the main pancreatic duct. Two subtypes of AIP have recently been identified. Type I AIP is more prevalent in elderly Asian males and is characterized by lymphoplasmacytic sclerosing pancreatitis, obliterative phlebitis, and infiltration of large numbers of IgG4-positive plasma cells. Type II AIP is more prevalent in Caucasians and is characterized by granulocyte epithelial lesions. Most patients with type I AIP have a significantly elevated serum IgG4 concentration, which is an important feature for diagnosis and for differentiating between AIP and other conditions such as pancreatic cancer. Extrapancreatic complications are common, such as sclerosing cholangitis, sclerosing sialadenitis, retroperitoneal fibrosis in type I AIP, and ulcerative colitis in type II AIP. A rapid response to glucocorticoids treatment is suggestive of AIP, but the relapse rate is high, warranting the use of immunosuppressant treatment. B-cell depletion with rituximab may be a promising therapy. The prognosis of AIP is generally benign if treated promptly, and spontaneous remission occurs in a proportion of patients.

A proposal of a diagnostic algorithm with validation of International Consensus Diagnostic Criteria for autoimmune pancreatitis in a Japanese cohort

BACKGROUND

Among many diagnostic criteria for autoimmune pancreatitis (AIP), the International Consensus Diagnostic Criteria (ICDC) first enabled us to diagnose and compare type 1 and type 2 AIP, which permitted tailoring individual diagnostic algorithms depending on local expertise. We compared them and validated ICDC with special reference to levels 1 and 2, and proposed a diagnostic algorithm for AIP in Japan.

METHODS

The diagnostic sensitivity of 5 major criteria (ICDC, Korean, Japanese-2011, Asian, and HISORt criteria) was compared, using 61 patients with AIP. Fifty six patients with pancreatic cancer served as a control. Pancreas imaging on computed tomography (CT) and endoscopic retrograde pancreatography (ERP) were independently evaluated by 3 pancreatologists (5, 10, and 20 years of career experience) and each diagnostic criterion of ICDC was validated with special reference to levels 1 and 2.

RESULTS

The sensitivities of 5 major criteria were 95.1% (ICDC), 90.2% (Korean), 86.9% (Japanese), 83.6% (Asian), and 83.6% (HISORt) with 100% of specificity in each. In the evaluation of pancreas imaging, diagnostic sensitivities of combination with CT and ERP in segmental/focal type AIP were significantly higher than single imaging (26% in CT (P < 0.01) or 35% in ERP (P < 0.05) vs 63% in CT + ERP), but not significantly different in the diffuse type.

CONCLUSIONS

Of the 5 criteria, ICDC is the most sensitive and useful for diagnosing AIP. We have proposed a diagnostic algorithm with CT for the diffuse type of AIP, and combination with CT + ERP followed by EUS-FNA for the segmental/focal type.

Current concept and diagnosis of IgG4-related disease in the hepato-bilio-pancreatic system

Recently, IgG4-related disease (IgG4-RD) has been recognized as a novel clinical entity with multiorgan involvement and unknown origin, associated with abundant infiltration of IgG4-positive cells. The Japanese research committee, supported by the Ministry of Health, Labor and Welfare of Japan, unified many synonyms for these conditions to the term "IgG4-RD" in 2009. The international symposium on IgG4-RD endorsed the comprehensive nomenclature as IgG4-RD, and proposed the individual nomenclatures for each organ system manifestations in 2011. Although the criteria for diagnosing IgG4-RD have not yet been established, proposals include the international pathological consensus (IPC) and the comprehensive diagnostic criteria (CDC) for IgG4-RD for general use, and several organ-specific criteria for organ-specialized physicians, e.g., the International consensus diagnostic criteria (ICDC) and the revised clinical diagnostic criteria in 2011 by the Japan Pancreas Society (JPS-2011) for type1 AIP; the Clinical Diagnostic Criteria 2012 for IgG4-sclerosing cholangitis (IgG4-SC-2012); the diagnostic criteria for IgG4-positive Mikulicz's disease by the Japanese Society for Sjogren's syndrome; and diagnostic criteria for IgG4-related kidney disease by the Japanese Society of Nephrology. In cases of probable or possible IgG4-RD diagnosed by the CDC, organ-specific diagnostic criteria should be concurrently used according to a diagnosis algorithm for IgG4-RD, with referral to a specialist.

Cholangiocarcinoma or IgG4-associated cholangitis: how feasible it is to avoid unnecessary surgical interventions?

OBJECTIVE

To evaluate the experience of a tertiary hepatopancreaticobiliary (HPB) center in the diagnostic approach and management of patients with suspicion of cholangiocarcinoma (CCa), focusing on excluding patients with IgG4-associated cholangitis (IAC) from unnecessary major surgical interventions.

METHODS

Between January 2008 and September 2010, a total number of 152 patients with suspicion of CCa underwent evaluation through a HPB multidisciplinary team meeting. Patients without tissue diagnosis were managed surgically or medically on the basis of probable presence of IAC as underlying pathology. Serology, immunostaining, and imaging were reviewed and analyzed according to the HISORt (Histology, Imaging, Serology, Other organ involvement, Response to therapy) criteria for IAC.

RESULTS

Tissue diagnosis during the diagnostic workup was achieved in 104 patients (68%), whereas the remaining 48 were classified as "highly suspicious for CCa" (n = 35) or as "probable IAC" (n = 13). Among 16 "highly suspicious for CCa" patients who underwent surgery, pathology revealed 2 patients harboring IAC (n = 1) and a benign chronic inflammatory biliary stricture (n = 1), respectively. Among the 13 patients with primarily medical management as "probable IAC," final diagnosis was CCa (n = 3) and IAC (n = 9), while 1 patient had no proven diagnosis. The accuracy of serum IgG4 for diagnosis of IAC reached 60%. Sensitivity and specificity of immunostaining for IAC in biopsy specimens were 56% and 89%, respectively. Imaging features suggesting IAC yielded sensitivity, specificity, and accuracy of 75%, 89%, and 83%, respectively. Initial imaging was revised at the referral institute in 75% of IAC patients (P = 0.009), while an isolated stricture (P = 0.038), a biliary mass (P = 0.006), and normal pancreas on computed tomography (P = 0.01) were statistically significant parameters for distinguishing between CCa and IAC. The mean time for establishing a diagnosis of IAC was 12.4 months (range: 2.5-32 months).

CONCLUSIONS

Differential diagnosis between CCa and IAC mandates high index of suspicion and low threshold for referral in high volume institutes. The delayed establishment of diagnosis particularly for CCa needs to be balanced versus avoiding unnecessary surgery for IAC. Imaging features may be most helpful for optimal management.

Utility of contrast-enhanced FDG-PET/CT in the clinical management of pancreatic cancer: impact on diagnosis, staging, evaluation of treatment response, and detection of recurrence

OBJECTIVES

Fluorodeoxyglucose (FDG)-positron emission tomography/contrast-enhanced computed tomography (PET/CE-CT) involving whole-body scanning first by non-CE-CT and FDG-PET followed by CE-CT has been used for detailed examination of pancreatic lesions. We evaluated PET/CE-CT images with regard to differential diagnosis, staging, treatment response, and postoperative recurrence in pancreatic cancer.

METHODS

Positron emission tomography/CE-CT was conducted in 108 patients with pancreatic cancer and in 41 patients with other pancreatic tumor diseases.

RESULTS

The maximum standardized uptake value (SUV(max)) overlapped in benign and malignant cases, suggesting that differential diagnosis of pancreatic tumors based on the SUV(max) is difficult. In the evaluation of staging in 31 resectable pancreatic cancer by PET/CE-CT, the diagnostic accuracy rate was more than 80% for most factors concerning local invasion and 94% for distant metastasis but only 42% for lymph node metastasis. Significant positive correlations were found between the SUV(max) and tumor size/markers, suggesting that SUV(max) may be a useful indicator for the treatment response. Regarding the diagnosis of the postoperative recurrence, PET/CE-CT correctly detected local recurrence in all the 11 cases of recurrence, whereas abdominal CE-CT detected only 7 of 11 cases, suggesting that PET/CE-CT is superior in this context.

CONCLUSIONS

Positron emission tomography/CE-CT is useful for the clinical management of pancreatic cancer.

Lymphadenopathy of IgG4-related disease: an underdiagnosed and overdiagnosed entity

Lymphadenopathy is a common occurrence in IgG4-related disease; it can appear before, concurrent with, or after the diagnosis of this disease, which is characterized by tumefactive sclerosing inflammatory lesions predominantly affecting extranodal sites, such as the pancreas, salivary gland, and lacrimal gland. Although multiple lymph node groups are commonly involved, constitutional symptoms are absent. The lymph nodes can show a broad morphologic spectrum, including multicentric Castleman disease-like (type I), follicular hyperplasia (type II), interfollicular expansion (type III), progressive transformation of germinal centers (type IV), and inflammatory pseudotumor-like (type V). All are characterized by an increase in IgG4+ plasma cells (>100 per high power field) and IgG4/IgG ratio (>40%). IgG4-related lymphadenopathy is both an underdiagnosed and overdiagnosed entity. The former is because of the fact that this entity has not been characterized until recently, while the latter results from pathologists' enthusiasm in diagnosing "new" entities and the lack of specificity of the morphologic and immunophenotypic features of IgG4-related lymphadenopathy. It is prudent to render this diagnosis only for patients with known IgG4-related disease or in the presence of corroborating clinical and laboratory findings (such as elderly men, systemic lymphadenopathy, elevated serum IgG4, IgG, and IgE but not IgM and IgA, and low titers of autoantibodies). Outside these circumstances, a descriptive diagnosis of "reactive lymphoid hyperplasia with increased IgG4+ cells" accompanied by a recommendation for follow-up will be appropriate because IgG4-related disease will likely ensue only in a minority of such patients.

Autoimmune pancreatitis and treatment approaches with case reports

OBJECTIVE

In this study, we aimed to review retrospectively the data of 10 patient who were treated and followed-up in our clinic and to review the current approaches in the diagnosis and treatment of autoimmune pancreatitis (AIP).

MATERIAL AND METHODS

We reviewed 10 patients retrospectively who were operated on and had the diagnosis of AIP histopathologically in the Ege University School of Medicine Department of General Surgery.

RESULTS

Between June 2001-November 2010, 10 patients who were diagnosed as AIP were examined retrospectively. Radiologically, a pancreatic mass was found in the pancreatic head with ultrasound in 7 (70%) of 10 patients and suspicious lesions were identified in the head of the pancreas in 3 (30%) patients. All patients were operated on in our clinic with the preliminary diagnosis of pancreatic head tumor; 8 patients underwent Whipple's procedure, 1 patient underwent pylorus preserving pancreaticoduodenectomy, and in 1 patient an exploratory pancreatic biopsy (frozen section) was carried out.

CONCLUSION

Autoimmune pancreatitis is a disease with increasing incidence and characterized by lymphoplasmocytic cell infiltration and fibrosis. Patients with a pancreatic mass, if there is an autoimmune disease or chronic pancreatitis suspected in the detailed history, it is necessary to evaluate patients in terms of AIP serologically to protect the patients from an incoorectng diagnosis and morbidity of surgery.

Autoimmune pancreatitis: an illustrated guide to diagnosis

Autoimmune pancreatitis (AIP) remains one of the rarer forms of pancreatitis but has become increasingly well recognized and widely diagnosed as it is an important differential, particularly due to the dramatic response to appropriate therapy. It is now best considered as part of a multisystem disease and the notion of "IgG4-related systemic sclerosing disease" has become widely recognized as the number of extra-pancreatic associations of AIP grows. More recently AIP has been classified into two subtypes: lymphoplasmacytic sclerosing pancreatitis (LPSP) and idiopathic duct-centric pancreatitis (IDCP) with distinct geographical, age and sex distributions for the two subtypes, in addition to different pathological characteristics. The role of imaging is crucial in AIP and should be considered in conjunction with clinical, serological, and histopathological findings to make the diagnosis. Radiologists are uniquely placed to raise the possibility of AIP and aid the exclusion of significant differentials to allow the initiation of appropriate management and avoidance of unnecessary intervention. Radiological investigation may reveal a number of characteristic imaging findings in AIP but appearances can vary considerably and the focal form of AIP may appear as a pancreatic mass, imitating pancreatic carcinoma. This review will illustrate typical and atypical appearances of AIP on all imaging modes. Emphasis will be placed on the imaging features that are likely to prove useful in discriminating AIP from other causes prior to histopathological confirmation. In addition, examples of relevant differential diagnoses are discussed and illustrated.

Pseudotumoral autoimmune pancreatitis mimicking a pancreatic cancer: a very difficult disease to diagnose

Autoimmune pancreatitis (AIP) is a rare disorder, although the exact prevalence is still unkown. It is a type of pancreatitis that is presumed to have an autoimmune aetiology, and is currently diagnosed based on a combination of 5 criteria. However, in this day and age, some patients with AIP are likely to be resected for the suspicion of malignancy. The authors report a case of pseudo-tumoral autoimmune pancreatitis, reviewing some literature about it and underlining the difficulty in the diagnosis. A 56-year-old patient was referred to our unit for upper abdominal pain. In his past medical history we note mellitus diabetes. The clinical examination was unremarkable. Laboratory data showed no abnormal values. Upper endoscopy showed antral gastritis. Transabdominal ultrasonography showed a hepatic steatosis and 5 angiomas. No computed tomography scan was made. Magnetic resonance imaging (MRI) showed 5 angiomas and a lesion of 20×20 mm of the pancreatic tail with decreased signal intensity on T1-weighted MR images, increased signal intensity on T2-weighted MR images. Due to concerns of pancreatic malignancy, the patient underwent open distal spleno-pancreatectomy. Histolo gical analysis of the resected specimen revealed no malignancy. Postoperatively, immunoglobulin G fraction 4 was slightly above of the upper limit of the normal range. After corticotherapy the patient is getting better. This case underlines the difficulties still encountered in the diagnosis of AIP. It has been frequently misdiagnosed as pancreatic cancer and caused unnecessary resection. In order to avoid unnecessary resections for an otherwise benign and easily treatable condition, it is urgent to refine diagnostic criteria and to reach an international consensus.

IgG4 Inflammatory Pseudotumor of the Kidney

Hyper-IgG4 disease is a rare systemic disorder that usually affects middle age males. It is characterized by elevated serum IgG4 levels and infiltration of organs by IgG4 positive plasma cells associated with fibrosis. Patients usually present with mass or masses in the involved organ that mimic neoplasia. While initially described in the pancreas, IgG4-related inflammatory tumors have been now described in many organs. We describe an unusual case of an IgG4-related pseudotumor of the kidney.

Autoimmune pancreatitis mimicking pancreatic cancer

Context:

Autoimmune pancreatitis is a particular type of pancreatitis of presumed autoimmune etiology, it is an entity distinct from all others forms of chronic pancreatitis, characterized by clinical, histopathological, radiographic, serologic and therapeutic features. This benign disease resembles pancreatic carcinoma both clinically and radiographically.

Case Report:

A 27-year-old man presented with obstructive jaundice and evocative image of pancreatic tumor. A pancreaticoduodenectomy (Whipple operation) was performed and pathological examination of the specimen diagnosed AIP. Patient responded well to a course of corticosteroids with resolution of clinical and biological disorders.

Conclusion:

Accurate and timely diagnosis of autoimmune pancreatitis is particularly important because steroid therapy is effective and pancreatic resection is not necessary.

Serum proteome profiling of pancreatitis using recombinant antibody microarrays reveals disease-associated biomarker signatures

PURPOSE

Pancreatitis is an inflammatory state of the pancreas, for which high-performing serological biomarkers are lacking. The aim of the present study was to evaluate the use of affinity proteomics for identifying potential markers of disease and stratifying pancreatitis subtypes.

EXPERIMENTAL DESIGN

High-content, recombinant antibody microarrays were applied for serum protein expression profiling of 113 serum samples from patients with chronic, acute, and autoimmune pancreatitis, as well as healthy controls. The sample groups were compared using supervised classification based on support vector machine analysis.

RESULTS

This discovery study showed that pancreatitis subtypes could be discriminated with high accuracy. Using unfiltered data, the individual subtypes, as well as the combined pancreatitis cohort, were distinguished from healthy controls with high AUC values (0.96-1.00). Moreover, characteristic protein patterns and AUC values in the range of 0.69-0.95 were observed for the individual pancreatitis entities when compared to each other, and to all other samples combined.

CONCLUSIONS AND CLINICAL RELEVANCE

This study demonstrated the potential of the antibody microarray approach for stratification of pancreatitis. Distinct candidate multiplex serum biomarker signatures for chronic, acute, and autoimmune pancreatitis were defined, which could enhance our fundamental knowledge of the underlying molecular mechanisms, and potentially lead to improved diagnosis.

Clinical analysis of 36 cases of autoimmune pancreatitis in China

BACKGROUND

To improve the early identification of autoimmune pancreatitis in China by a retrospective analysis of clinical data from AIP patients.

METHODOLOGY/PRINCIPAL FINDINGS

The analysis included 36 patients admitted by the surgery department of our hospital from January 2003 to October 2011 whose postoperative pathological confirmations were consistent with the histological criteria of Honolulu Consensus Document. The clinical phenotypes associated with the histopathologic patterns of LPSP and IDCP were referred to as type 1 and type 2 of AIP, respectively. A retrospective analysis of clinical features, serological data, pathological findings and imageological records was performed in line with the subtypes of AIP. Type 1 showing a sex predilection (males) was commonly more dominant than type 2 in all AIP. Type 2 without a gender predilection was, on average, a decade younger than type 1. Type 1 was inferior to type 2 in ALT, ALP and γ-GT with statistical significance (P = 0.044, 0.025 and 0.013). Type 1 was inferior to type 2 in AST with difference close to statistical significance (P = 0.072). Histopathology revealed frequent lymphoplasmacytic infiltration with less frequent infiltration of neutrophils, eosinophils and fibroblasts. Diffuse and intensive interstitial fibrosis could be seen. The changes of pancreatic head were more frequently seen in type 2 than in type 1 (P = 0.05). Plasma cells staining of IgG4 at a density of over 30 or more cells per high-power field appeared to be a specific finding in China with type 1. Imageology found a diffusely or focally enlarged pancreas, most frequently a mass or enlargement in the pancreatic head, characteristic capsule-like rim, calcification or pancreatic calculus and cystic degeneration.

CONCLUSIONS/SIGNIFICANCE

AIP is a unique type of chronic pancreatitis and has distinctive serological, pathological and imageological characteristics, which should be used for differentiation from pancreatic cancer.

Autoimmune pancreatitis and non-necrotizing acute pancreatitis: computed tomography pattern

OBJECTIVES

To retrospectively differentiate diffuse autoimmune pancreatitis from non-necrotizing acute pancreatitis at clinical onset with multi detector row computed tomography.

METHODS

36 Patients suffering from diffuse autoimmune pancreatitis (14) or non-necrotizing acute pancreatitis (22) were enrolled. Qualitative analysis included stranding, retroperitoneal fluid film, capsule-like rim enhancement and pleural effusion. In quantitative analysis pancreatic density was measured in all phases. The vascularization behaviour was assessed using the relative enhancement rate across all phases.

RESULTS

Pancreatic density resulted lower in non-necrotizing acute pancreatitis compared to diffuse autoimmune pancreatitis patients in pre-contrast phase and higher in pancreatic phase. Relative enhancement rate evaluation confirmed different vascularization behaviours of the two diseases. Only non-necrotizing acute pancreatitis Patients presented peripancreatic stranding and fluid in the retromesenteric interfascial plane.

CONCLUSIONS

Multi detector row computed tomography is a useful technique for differentiating diffuse autoimmune pancreatitis from non-necrotizing acute pancreatitis at clinical onset. Peripancreatic stranding and retroperitoneal fluid film, characteristic of non-necrotizing acute pancreatitis, and late-phase peripheral rim enhancement, characteristic of diffuse autoimmune pancreatitis, provide qualitative clues to the differentiation. A quantitative study of contrast enhancement patterns, considering the relative enhancement rate, can assist in the differential diagnoses of two diseases.

Endoscopic ultrasonographic study of autoimmune pancreatitis and the effect of steroid therapy

BACKGROUND

Recently, endoscopic ultrasonography (EUS) has been used for the diagnosis of chronic pancreatitis (CP); however, EUS diagnosis of autoimmune pancreatitis (AIP) varies among different researchers. We investigated EUS findings in AIP and retrospectively analyzed them before and after steroid therapy.

PATIENTS AND METHODS

The subjects were 32 patients with AIP and the EUS images of the pancreatic parenchyma were evaluated with reference to the Sahai criteria. Patients' background factors detected by EUS were analyzed statistically. Peroral steroid was given to 23 of the 32 patients. EUS was also performed 2 weeks after the initiation of therapy in 14 of the 23 patients, and the changes in EUS were investigated. Microscope images were compared with EUS images in one patient who underwent surgical resection.

RESULTS

EUS results included hyperechoic strands in 26 (81.3%) and lobularity in 17 (53.1%) patients. The patients' background factors included the presence of splenic and/or portal vein occlusion or narrowing around the pancreas in patients who had neither hyperechoic strands nor lobularity (p = 0.002, p = 0.004). The numbers of EUS findings before versus after steroid therapy were 11 versus 5 for hyperechoic strands and 7 versus 2 for lobularity. Microscope images showed the coexistence of relatively well-maintained lobular structures of pancreatic acini and almost complete loss of such structures.

CONCLUSION

EUS findings in AIP were similar to those in early-stage CP, and hyperechoic strands and lobularity seem to suggest a condition under which the histology of lobular structures of the pancreatic acini is relatively well-maintained. EUS results had improved within about 2 weeks of steroid therapy.

Nationwide epidemiological survey of autoimmune pancreatitis in Japan

OBJECTIVES

To clarify the clinicoepidemiological features of autoimmune pancreatitis (AIP) in Japan, the nationwide survey was conducted.

METHODS

Patients with AIP who had visited the selected hospitals in 2007 were surveyed. Autoimmune pancreatitis was diagnosed according to the Japanese clinical diagnostic criteria 2006. The study consisted of 2-stage surveys: the number of patients with AIP was estimated by the first questionnaire and their clinical features were assessed by the second questionnaire.

RESULTS

The estimated total number of AIP patients in 2007 was 2790 (95% confidence interval, 2540-3040), with an overall prevalence rate of 2.2 per 100,000 populations. The number of patients, who were newly diagnosed as AIP, was estimated to be 1120 (95% confidence interval, 1000-1240), with an annual incidence rate of 0.9 per 100,000 populations. Sex ratio (male to female) was 3.7, and the mean (SD) age was 63.0 (11.4) years. Among the 546 patients whose clinical information was obtained, 87.6% of the patients presented high serum immunoglobulin G4 levels (≥ 135 mg/dL), and 83% received steroid therapy.

CONCLUSIONS

The data represent the current clinical features of AIP in Japan. From the results, most AIP patients in Japan can be categorized to type 1 AIP according to the recent classification of AIP.

Prevalence of IgG4-Related Disease in Japan Based on Nationwide Survey in 2009

The number of patients with autoimmune pancreatitis who visited hospitals in Japan in 2007 was approximately 2709 (95% confidence interval; range 2540–3040). Because IgG4-related disease is a new clinical entity, there are no data with regard to its prevalence. To estimate the number of patients with IgG4-related disease in Japan, we randomly selected hospitals using stratification and asked them how many patients they had with IgG4-related disease in 2009. The number of patients with Mikulicz's disease, IgG4-related retroperitoneal fibrosis, IgG4-related renal disease, IgG4-related pulmonary disease, and IgG4-related lymphadenopathy who visited hospitals in Japan in 2009 was approximately 4304 (95% confidence interval; range 3360–5048), 272 (95% confidence interval; range 264–306), 57 (95% confidence interval; range 47–66), 354 (95% confidence interval; range 283–424), and 203 (95% confidence interval; range 187–240), respectively. The total number of patients with IgG4-related disease without autoimmune pancreatitis in Japan was approximately 5190 (95% confidence interval; range 4141–6084). The male : female ratio was 1 : 0.77, and the average of age of disease onset was 58.8 years. The total number of patients with IgG4-related disease in Japan in 2009, including autoimmune pancreatitis, was approximately 8000.

Spontaneous regression of pancreatic cancer: real or a misdiagnosis?

Spontaneous tumor regression has been subject of numerous studies and speculations for many years. This phenomenon is exceptional, but well reported, in some types of tumors, but not in pancreatic cancer. Pancreatic cancer has the worst five-year survival rate of any cancer. Despite numerous molecular studies and clinical approaches, using several mouse models, this cancer responds poorly to the existing chemotherapeutic agents and progress on treatment remains elusive. Although pancreatic cancer tumors seldom undergo spontaneous regression, and some authors take that with skepticism, there are some cases reported in the literature. However, the variability in the description of the reports and technical details could make this process susceptible to misdiagnosis. Distinguishing between different types of pancreatic carcinoma should be taken with caution as they have wide differences in malignant potential. Diseases such as pancreatic benign tumors, insulinomas, or autoimmune pancreatitis could be responsible for this misdiagnosis as a pancreatic cancer. Here we review different cases reported, their clinical characteristics, and possible mechanisms leading to spontaneous regression of pancreatic cancer. We also discuss the possibilities of misdiagnosis.

MR imaging of IgG4-related disease in the head and neck and brain

SUMMARY

IgG4-related disease is characterized by histologic fibrosis with IgG4-positive plasma cell infiltration. Our study evaluated MR imaging features of IgG4-related disease in the head and neck and brain. Images from 15 patients were retrospectively evaluated for the location, signal intensity, and enhancement patterns of lesions. Lacrimal gland enlargement was observed in 8 cases. Other lesions included orbital pseudotumor in 5, pituitary enlargement in 5, and cranial nerve enlargement in 7; the infraorbital nerve was involved in 4. All lesions were hypointense on T2-weighted images, which is typical for IgG4-related lesions. Multiple sites were involved in the head and neck and brain in 11 patients. The diagnosis of IgG4-related disease should be considered in a patient presenting with T2 hypointense lacrimal gland, pituitary, or cranial nerve enlargement, or a T2 hypointense orbital mass, especially if multiple sites in the head and neck are involved in the presence of elevated serum IgG4.

Are Classification Criteria for IgG4-RD Now Possible? The Concept of IgG4-Related Disease and Proposal of Comprehensive Diagnostic Criteria in Japan

Recent studies suggest simultaneous or metachronous lesions in multiorgans characterized by elevated serum levels of IgG4 and abundant infiltration of IgG4-positive plasma cells with various degrees of fibrosis. Two Japanese research committees for IgG4-RD, one from fibrosclerosis (Okazaki team) and the other from lymph proliferation (Umehara team) supported by the “Research Program for Intractable Disease” of the Ministry of Health, Labor, and Welfare of Japan, have agreed with the unified nomenclature as “IgG4-RD” and proposed the comprehensive diagnostic criteria (CDC) for IgG4-RD. Validation of the CDC demonstrated satisfactory sensitivity for the practical use of general physicians and nonspecialists but low sensitivity in the organs to be difficult in taking biopsy specimens such as type1 autoimmune pancreatitis (IgG4-related AIP), compared with IgG4-related sialadenitis/dacryoadenitis (Mikulicz's disease) and IgG4-related kidney disease. Although the diagnostic criteria covering all IgG4-RD are hard to be established, combination with the CDC and organ-specific diagnostic criteria should improve sensitivity.

Autoimmune pancreatitis: assessment of the enhanced duct sign on multiphase contrast-enhanced computed tomography

PURPOSE

To assess the usefulness of the computed tomography (CT) finding of main pancreatic duct (MPD) wall enhancement, termed the "enhanced duct sign", for diagnosis of autoimmune pancreatitis (AIP) in comparison with diagnosis of pancreatic carcinoma and chronic pancreatitis.

MATERIALS AND METHODS

Two radiologists independently evaluated the presence or absence of the enhanced duct sign on multiphase contrast-enhanced CT in patients with AIP (n=55), pancreatic carcinoma (n=50), and chronic pancreatitis (n=50). The sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of AIP were calculated. In patients demonstrating the enhanced duct sign, additional findings were evaluated by consensus.

RESULTS

The enhanced duct sign was more frequently observed in patients with AIP (37/55, 67%) than in patients with pancreatic carcinoma (5/50, 10%) or chronic pancreatitis (0/50, 0%) (P<0.05). The sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of the finding were 0.67, 0.95, 0.85, 0.88, and 0.84, respectively. In AIP, the lumen within the enhanced duct was completely or partially invisible in 29 of 37 (78%) patients, and the enhanced duct was observed within the affected pancreatic parenchyma in 35 of 37 (95%) patients. In pancreatic carcinoma, the lumen within the enhanced duct was visible in all patients (5/5, 100%), and the enhanced duct was observed downstream of the tumor (5/5, 100%).

CONCLUSION

The enhanced duct sign is highly specific of AIP.

Clinical and Immunopathologic Profile of Mexican Patients with IgG4 Autoimmune Pancreatitis

Autoimmune pancreatitis is part of the spectrum of IgG4-associated diseases. Its diagnostic criteria and histological subtypes have been formally proposed recently and although based on current data it has been suggested that there are differences in clinical presentation among populations, more research is needed to properly establish if this heterogeneity exists. In this paper, we describe 15 cases of autoimmune pancreatitis diagnosed at a Mexican centre of reference, all of them associated to the lymphoplasmocytic sclerosing pancreatitis variant. The mean age at the onset of symptoms was 47.5 ± 14.4 years, and 53% of patients were male. The main manifestations were weight loss (87%), obstructive jaundice (53%), and acute (27%) and chronic (27%) pancreatitis. Only 20% of patients had high IgG4 serum levels at the time of diagnosis. All patients receiving prednisone responded favourably, both in their pancreatic and extrapancreatic manifestations. Clinical manifestations of Mexican patients showed certain differences with respect to those usually reported.

Differentiation of autoimmune pancreatitis with pancreatic carcinoma remains a challenge to physicians

OBJECTIVE

The aim of this study was to summarize the clinical features of autoimmune pancreatitis (AIP) and review the advances in the differential diagnosis with pancreatic carcinoma, thus help to make a correct diagnosis and avoid unnecessary surgery in clinical practice.

METHODS

Five patients diagnosed as AIP in accordance with the HISORt criteria in Zhongshan Hospital, Fudan University from 2008 to 2010 were enrolled in the study. Clinical features were analyzed and related literature was reviewed.

RESULTS

Progressive jaundice and abdominal pain were the most frequent symptoms, as well as weight loss, together with serological changes such as elevation of alkaline phosphatase, γ-glutamyl-transpeptidase and serum bilirubin. Two of them showed high serum immunoglobulin G4 (IgG4) levels. Both focal and diffuse changes were found on computed tomography and magnetic resonance imaging. Two of our patients underwent operation because of a high suspicion of malignant tumor, and steroid therapy was administered to the other three patients diagnosed as AIP. No relapse was observed during the follow-up duration of all the patients.

CONCLUSIONS

Although some recent advances have been made to help the diagnosis of AIP, the differentiation between AIP and pancreatic carcinoma is still a challenge. Clinicians must remember to exclude AIP before making a diagnosis of pancreatic carcinoma.

Clinical differences between mass-forming autoimmune pancreatitis and pancreatic cancer

OBJECTIVE

Autoimmune pancreatitis (AIP) needs to be differentiated from pancreatic cancer (PC). We aimed to clarify the findings specific for AIP by comparing the clinical differences between mass-forming AIP and PC.

MATERIAL AND METHODS

We retrospectively compared 36 patients with mass-forming AIP and 60 with PC without metastasis regarding clinical, imaging, serological, histological differences and other organ involvement (OOI). We evaluated the sensitivity, specificity and accuracy of these findings for the differential diagnosis between AIP and PC.

RESULTS

The findings 100% specific for AIP were a capsule-like rim on computed tomography (CT), skipped lesion of main pancreatic duct (MPD) on endoscopic retrograde pancreatography (ERP) or magnetic resonance cholangiopancreatography (MRCP), γ-globulin > 2 g/dl, OOI (extrapancreatic biliary stricture, salivary gland swelling and retroperitoneal fibrosis) and ruling out PC by histopathological findings of endoscopic ultrasonography-guided fine-needle aspiration. The findings over 90% specific were IgG4 > 280 mg/dl (98%), IgG > 1800 mg/dl (97%), maximal diameter of upstream MPD < 5 mm on MRCP (95%) and IgG4 > 135 mg/dl (94%), respectively.

CONCLUSIONS

Clinical, imaging, serological, histological findings and OOI differed between mass-forming AIP and PC. Capsule-like rim on CT, skipped lesion of MPD on ERP or MRCP, IgG4 > 280 mg/dl, and OOI were highly specific findings for AIP. These findings are useful in the differential diagnosis of mass-forming AIP from PC.

Regulatory T cells in type 1 autoimmune pancreatitis

Autoimmune pancreatitis (AIP) is a newly recognized pancreatic disorder. Recently, International Consensus Diagnostic Criteria for AIP (ICDC) was published. In this ICDC, AIP was classified into Type 1 and Type 2. Patients with Type 1 AIP have several immunologic and histologic abnormalities specific to the disease, including increased levels of serum IgG4 and storiform fibrosis with infiltration of lymphocytes and IgG4-positive plasmacytes in the involved organs. Among the involved organs showing extrapancreatic lesions, the bile duct is the most common, exhibiting sclerosing cholangitis (IgG4-SC). However, the role of IgG4 is unclear. Recently, it has been reported that regulatory T cells (Tregs) are involved in both the development of various autoimmune diseases and the shift of B cells toward IgG4, producing plasmacytes. Our study showed that Tregs were increased in the pancreas with Type 1 AIP and IgG4-SC compared with control. In the patients with Type 1 AIP and IgG4-SC, the numbers of infiltrated Tregs were significantly positively correlated with IgG4-positive plasma cells. In Type 1 AIP, inducible costimulatory molecule (ICOS)⁺ and IL-10⁺ Tregs significantly increased compared with control groups. Our data suggest that increased quantities of ICOS⁺ Tregs may influence IgG4 production via IL-10 in Type 1 AIP.

The Utility of Serum IgG4 Concentrations as a Biomarker

IgG4-related disease is a new disease entity involving IgG4 in its clinical presentation and having 6 characteristic features: (1) systemic involvement; (2) solitary or multiple lesions showing diffuse or localized swelling, masses, nodules, and/or wall thickening on imaging; (3) high serum IgG4 concentration >135 mg/dL; (4) abundant infiltration of lymphoplasmacytes and IgG4-bearing plasma cells; (5) a positive response to corticosteroid therapy; and (6) complications of other IgG4-related diseases. To date, most IgG4-related diseases have been recognized as extrapancreatic lesions of autoimmune pancreatitis. This paper will discuss the utility of IgG4 as a biomarker of IgG4-related diseases, including in the diagnosis of autoimmune pancreatitis and its differentiation from pancreatic cancer, in the prediction of relapse, in the long-term follow-up of patients with autoimmune pancreatitis and normal or elevated IgG4 concentrations, and in patients with autoimmune pancreatitis and extrapancreatic lesions, as well as the role of IgG4 in the pathogenesis of IgG4-related disease.

Strategy to differentiate autoimmune pancreatitis from pancreas cancer

Autoimmune pancreatitis (AIP) is a newly described entity of pancreatitis in which the pathogenesis appears to involve autoimmune mechanisms. Based on histological and immunohistochemical examinations of various organs of AIP patients, AIP appears to be a pancreatic lesion reflecting a systemic “IgG4-related sclerosing disease”. Clinically, AIP patients and patients with pancreatic cancer share many features, such as preponderance of elderly males, frequent initial symptom of painless jaundice, development of new-onset diabetes mellitus, and elevated levels of serum tumor markers. It is of uppermost importance not to misdiagnose AIP as pancreatic cancer. Since there is currently no diagnostic serological marker for AIP, and approach to the pancreas for histological examination is generally difficult, AIP is diagnosed using a combination of clinical, serological, morphological, and histopathological features. Findings suggesting AIP rather than pancreatic cancer include: fluctuating obstructive jaundice; elevated serum IgG4 levels; diffuse enlargement of the pancreas; delayed enhancement of the enlarged pancreas and presence of a capsule-like rim on dynamic computed tomography; low apparent diffusion coefficient values on diffusion-weighted magnetic resonance image; irregular narrowing of the main pancreatic duct on endoscopic retrograde cholangiopancreatography; less upstream dilatation of the main pancreatic duct on magnetic resonance cholangiopancreatography, presence of other organ involvement such as bilateral salivary gland swelling, retroperitoneal fibrosis and hilar or intrahepatic sclerosing cholangitis; negative work-up for malignancy including endoscopic ultrasound-guided fine needle aspiration; and steroid responsiveness. Since AIP responds dramatically to steroid therapy, accurate diagnosis of AIP can avoid unnecessary laparotomy or pancreatic resection.

Use of samples from endoscopic ultrasound-guided 19-gauge fine-needle aspiration in diagnosis of autoimmune pancreatitis

BACKGROUND & AIMS

Histologic techniques are used to distinguish autoimmune pancreatitis (AIP) from pancreatic malignancies and to confirm the etiology of pancreatitis. Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) is a well-established technique used in the diagnosis of pancreatic cancer. However, it is unclear whether specimens obtained from pancreatic lesions by EUS-FNA are adequate for the histologic diagnosis of AIP, because the evaluation of tissue architecture and immunostaining assays usually require larger samples.

METHODS

We evaluated samples collected by EUS-FNA with a conventional 19-gauge needle by histologic analysis, looking for features of AIP. We analyzed data from 44 patients who were diagnosed with AIP and underwent EUS-FNA with a 19-gauge needle from January 2004 to September 2010. The FNA specimens were reviewed by histologic analysis; AIP was diagnosed based on the presence of lymphoplasmacytic sclerosing pancreatitis or immunoglobulin (Ig)G4-positive plasma cells in the infiltrate.

RESULTS

The specimen amount was inadequate from 3 patients. Among the remaining 41 patients, histopathologic analysis revealed lymphoplasmacytic sclerosing pancreatitis in 17 samples and IgG4-positive plasma cells in 5 (3 samples were positive for both); no samples had granulocytic epithelial lesions. Therefore, 19 patients (43%) were diagnosed with AIP based on histologic analysis. One patient had temporary abdominal pain.

CONCLUSIONS

EUS-FNA, with a 19-gauge needle, is a safe and reliable procedure for obtaining pancreatic samples for the histologic analysis of AIP. Although it does not have a high diagnostic yield, it might be useful in patients without typical features of AIP because it would allow patients to avoid surgery.

Three cases of bronchial asthma preceding IgG4-related autoimmune pancreatitis

BACKGROUND

Autoimmune pancreatitis is characterized by diffuse swelling of the pancreas and a high serum immunoglobulin (Ig) G4 concentration. Histopathologically, dense infiltration of lymphocytes and IgG4-positive plasma cells with fibrosis are seen in the pancreas. Although allergic diseases complicating autoimmune pancreatitis have been reported, the clinical features of bronchial asthma complicated by autoimmune pancreatitis remain unclear.

CASE SUMMARY

We report three cases of bronchial asthma preceding the onset of type 1 autoimmune pancreatitis by 3 months to 30 years. All three cases were males with high serum IgG, IgG4, and IgE concentrations. The radioallergosorbent tests were positive for common allergens such as mites and house dust. One case had a pulmonary manifestation that proved to be an inflammatory pseudotumor of the lung with an accumulation of IgG4-positive plasma cells. The asthma symptom was ameliorated by oral prednisolone therapy for autoimmune pancreatitis, and when the corticosteroid doses were reduced, asthma became worse in all three cases.

DISCUSSION

It is possible that atopy and increased Th2 cell activity are related to a higher coincidence of IgG4-related diseases such as type 1 autoimmune pancreatitis. Because the present cases are few in number, further studies are necessary.