Pancreatic cancer with a high serum IgG4 concentration

Risk of malignancies in IgG4-related disease

IgG4-related disease (IgG4-RD) is considered a systemic, chronic, and inflammatory disorder that is characterized by the enlargement of involved organs, elevated levels of IgG4, and abundant infiltration of plasmacytes with IgG4 and fibrosis in involved organs. It is necessary to differentiate IgG4-RD from malignant tumors. Recently we have looked at case reports of IgG4-RD with malignancy that was discovered at systemic screening. In this study, we analyzed the relationship between IgG4-RD and malignancies. The study subjects were 106 patients with IgG4-RD who had been referred to our hospital since April 1997. We analyzed the clinical characteristics of IgG4-RD patients who had cancer that was observed upon the initial diagnosis of IgG4-RD or that occurred during an average follow-up period of 3.1 years. Using data from national cancer registries that monitor cancer incidence in Japan, we evaluated the standardized incidence ratio (SIR) for malignancies in IgG4-RD. Malignancies were observed in 11 of the IgG4-RD patients (10.4%). The malignancies were all different and included lung cancer, colon cancer, and lymphoma. With the exception of the age at which the IgG4-RD diagnosis was made, there were no common features in patients with cancer and those without. The SIR for these malignancies in IgG4-RD was 383.0, which was higher than that for the general population. We should be cognizant of the possible existence of malignancies in patients with IgG4-RD at the time of diagnosis and during follow-up care.

A novel clinical entity, IgG4-related disease (IgG4RD): general concept and details

IgG4-related disease (IgG4RD) is a novel clinical disease entity characterized by elevated serum IgG4 concentration and tumefaction or tissue infiltration by IgG4-positive plasma cells. IgG4RD may be present in a certain proportion of patients with a wide variety of diseases, including Mikulicz’s disease, autoimmune pancreatitis, hypophysitis, Riedel thyroiditis, interstitial pneumonitis, interstitial nephritis, prostatitis, lymphadenopathy, retroperitoneal fibrosis, inflammatory aortic aneurysm, and inflammatory pseudotumor. Although IgG4RD forms a distinct, clinically independent disease category and is attracting strong attention as a new clinical entity, many questions and problems still remain to be elucidated, including its pathogenesis, the establishment of diagnostic criteria, and the role of IgG4. Here we describe the concept of IgG4RD and up-to-date information on this emerging disease entity.

Serial changes of elevated serum IgG4 levels in IgG4-related systemic disease

OBJECTIVE

Autoimmune pancreatitis (AIP) and Mikulicz's disease have recently been recognized as pancreatic or salivary gland lesions of IgG4-related systemic disease. These are frequently associated with elevated serum IgG4 levels. This study aimed to clarify clinical implications of serial changes of elevated serum IgG4 levels in IgG4-related systemic diseases.

METHODS

Serial changes of elevated serum IgG4 levels were examined in patients with IgG4-related systemic diseases. Patients Serial changes of elevated serum IgG4 levels were examined in 44 patients: AIP (n=24), Mikulicz's disease (n=8), pancreatic cancer (n=5), bile duct cancer (n=1), sclerosing cholangitis (n=1), hypereosinophilic syndrome (n=1), chronic thyroiditis (n=1), hypophysitis (n=1), idiopathic pancreatitis (n=1), and Behcet's disease (n=1).

RESULTS

The serum IgG4 levels decreased in all patients with AIP and Mikulicz's disease after steroid therapy. The serum IgG4 levels were normalized in 46% of AIP patients and 38% of Mikulicz's disease patients. The serum IgG4 levels were not normalized at remission in 3 of 4 relapsed AIP patients, and re-elevation of serum IgG4 levels was detected in all relapsed patients. Elevated serum IgG4 levels decreased in 3 patients with pancreatic cancer after resection or chemotherapy, and decreased in patients with hypereosinophilic syndrome, sclerosing cholangitis, and hypophysitis after steroid therapy.

CONCLUSION

Measurement of serial serum IgG4 levels is useful to determine the disease activity of IgG4-related systemic diseases.

[IgG4-related Mikulicz's disease: a report of 3 cases]

INTRODUCTION

We report three cases of hyper-IgG4 disease with synchronous or asynchronous lymphocytic infiltration onset, IgG4 positive plasma cell infiltration, and fibril formation in multiple exocrine glands and extranodal organs. IgG4-related sialadenitis attracting recent attention has yet to be clarified as a clinical entity.

CASE REPORT

Case 1, a 61-year-old man, had a submandibular gland sample showing IgG4-positive plasma cell infiltration. Case 2, a 61-year-old man, was diagnosed with IgG4-related Mikulicz's disease confirmed by a sublingual gland sample. Case 3, a 57-year-old woman, had a diagnosis of IgG4-related Mikulicz's disease confirmed based on labial and sublingual gland samples. All reported oral dryness and bilateral submandibular swelling. Cases 1 and 2 recovered following Predonine administration tapered from 30 or 20 mg.

DISCUSSION

IgG4-related Mikulicz's disease must be recognized as a clinical entity, together with its diagnostic criteria and treatment. Sublingual gland biopsy should be done to confirm its diagnosis following sublingual gland swelling.

IgG4-related meningeal disease: clinico-pathological features and proposal for diagnostic criteria

IgG4-related disease has evolved from originally being recognized as a form of pancreatitis to encompass diseases of numerous organs including the hypophysis and one reported case of dural involvement. A search of the University of Virginia, Division of Neuropathology files for 10 years identified ten cases of unexplained lymphoplasmacytic meningeal inflammation that we then evaluated using immunohistochemical stains for IgG4 and IgG. Ten control cases including sarcoidosis (4), tuberculosis (1), bacterial abscess (2), Langerhans cell histiocytosis (2), and foreign body reaction (1) were also examined. The number of IgG4-positive plasma cells was counted in five high power fields (HPFs) and an average per HPF was calculated. Cases that contained greater than ten IgG4-positive cells/HPF were considered to be IgG4-related. Five of the study cases met these criteria, including one case of leptomeningeal inflammation. All cases exhibited the typical histological features of IgG4-related disease including lymphoplasmacytic inflammation, fibrosis, and phlebitis. The dural-based lesions appear to represent a subset of the cases historically diagnosed as idiopathic hypertrophic pachymeningitis. While the leptomeningeal process most closely resembles non-vasculitic autoimmune inflammatory meningoencephalitis. Given these findings, IgG4-related meningitis should be considered in the differential diagnosis of meningeal inflammatory lesions after stringent clinical and histologic criteria are used to rule out other possible diagnoses.

IgG4-related sclerosing disease: a critical appraisal of an evolving clinicopathologic entity

An elevated serum titer of immunoglobulin G4 (IgG4), the least common (3% to 6%) of the 4 subclasses of IgG, is a surrogate marker for the recently characterized IgG4-related sclerosing disease. The syndrome affects predominantly middle-aged and elderly patients, with male predominance. The patients present with symptoms referable to the involvement of 1 or more sites, usually in the form of mass lesions. The prototype is IgG4-related sclerosing pancreatitis (also known as autoimmune pancreatitis), most commonly presenting as painless obstructive jaundice with or without a pancreatic mass. Other common sites of involvement are the hepatobiliary tract, salivary gland, orbit, and lymph node, but practically any organ-site can be affected, such as retroperitoneum, aorta, mediastinum, soft tissue, skin, central nervous system, breast, kidney, prostate, upper aerodigestive tract, and lung. The patients usually have a good general condition, with no fever or constitutional symptoms. Common laboratory findings include raised serum globulin, IgG, IgG4, and IgE, whereas lactate dehydrogenase is usually not raised. Some patients have low titers of autoantibodies (such as antinuclear antibodies and rheumatoid factor). The disease often shows excellent response to steroid therapy. The natural history is characterized by the development of multiple sites of involvement with time, sometimes after many years. However, the disease can remain localized to 1 site in occasional patients. The main pathologic findings in various extranodal sites include lymphoplasmacytic infiltration, lymphoid follicle formation, sclerosis and obliterative phlebitis, accompanied by atrophy and loss of the specialized structures of the involved tissue (such as secretory acini in pancreas, salivary gland, or lacrimal gland). The relative predominance of the lymphoplasmacytic and sclerotic components results in 3 histologic patterns: pseudolymphomatous, mixed, and sclerosing. Immunostaining shows increased IgG4+ cells in the involved tissues (>50 per high-power field, with IgG4/IgG ratio >40%). The lymph nodes show multicentric Castleman disease-like features, reactive follicular hyperplasia, interfollicular expansion, or progressive transformation of germinal centers, with the unifying feature being an increase in IgG4+ plasma cells on immunostaining. The nature and pathogenesis of IgG4-related sclerosing disease are still elusive. Occasionally, the disease can be complicated by the development of malignant lymphoma and possibly carcinoma.

Refractory gastric ulcer with abundant IgG4-positive plasma cell infiltration: A case report

We describe a 77-year-old man with refractory gastric ulcer that worsened after Helicobacter pylori eradication therapy. Pathology showed marked infiltration of IgG4-positive plasma cells in the gastric lesions, which led us to suspect IgG4-related sclerosing disease. To the best of our knowledge, this is the first report of IgG4-related gastric ulcer without the main manifestation of autoimmune pancreatitis.

Autoimmune pancreatitis: a challenging diagnostic puzzle for clinicians

Autoimmune pancreatitis is a form of pancreatitis with autoimmune stigmata that may present as either focal or diffuse gland involvement. In focal forms, autoimmune pancreatitis shares demographic, clinical, biochemical and imaging features with pancreatic cancer. Since autoimmune pancreatitis is a benign disease and steroid therapy can rapidly resolve symptoms, improve radiological findings and avoid unnecessary surgery, the current clinical challenge is how to differentiate autoimmune pancreatitis from pancreatic neoplasia. Even though definitive diagnosis of the disease is difficult, several diagnostic criteria have been proposed and progress has been made in imaging studies. The management of this unique form of pancreatitis should, therefore, be handled in centres with knowledge of all aspects of the disease. This article briefly reviews clinical aspects of autoimmune pancreatitis with a focus on its diagnostic imaging and management.

Small invasive ductal adenocarcinoma of the pancreas associated with lymphoplasmacytic sclerosing pancreatitis

An asymptomatic 59-year-old man underwent pancreatoduodenectomy for a pancreatic mass that was discovered during a health check-up. Histopathology indicated typical features of lymphoplasmacytic sclerosing pancreatitis (LPSP) or autoimmune pancreatitis along with the presence of abundant IgG4-positive plasma cells throughout the mass. A small invasive ductal adenocarcinoma was observed in the center of the area affected by LPSP. The present case suggests that LPSP may be closely related to carcinogenesis of the pancreas.

[IgG4-related disease-the diagnostic confusion and how to avoid it]

Since Hamano et al. have first reported serum IgG4 elevation in sclerosing pancreatitis in 2001, various systemic disorders have been reported to be related to elavated IgG4, and many names have been proposed from the point of view of the systemic condition. Despite similarities in the organs damaged in IgG4-related Mikulicz's disease and Sjögren's syndrome, there are marked clinical and pathological differences between the two entities. IgG4-related Mikulicz's disease and Küttner's tumor are related diseases and complete differentiation is very difficult. The majority of cases diagnosed with autoimmune pancreatitis in Japan are IgG4-related sclerosing pancreatitis, and it should be recognized that this is distinct from the western type. There is a likelihood that cases once diagnose as Castleman's disease that showed good responsiveness to glucocorticoid treatment may have been IgG4-related lymphadenopathy, and should be re-assessed in light of recent findings. Diagnosis of IgG4-related disease is defined by both 1) Elevated serum IgG4 (>135 mg/dl) and 2) Histopathological features including lymphocyte and IgG4(+) plasma cell infiltration (IgG4(+) plasma cells/IgG(+) plasma cells >50% on a highly-magnified slide checked in five points), however differential diagnosis from other distinct disorders, such as sarcoidosis, Castleman's disease, Wegener's granulomatosis, lymphoma, cancer, and other existing conditions is necessary. To avoid diagnostic confusion, simpler and more scientific names should be used where disease-specific pathogenesis or markers have been ascertained.

Salivary duct carcinoma arising in IgG4-related autoimmune disease of the parotid gland

Hyper IgG4 disease or IgG4-related sclerosing/autoimmune disease is a multisystem condition characterized histologically by fibrosis, lymphoplasmacytic infiltration, and abundant IgG4 plasma cells associated with raised serum IgG4 levels. We present a case of salivary duct carcinoma of the parotid gland in a background of chronic sclerosing sialadenitis that also involved the submandibular gland with associated regional lymphadenopathy. The serology showed raised total IgG levels of 16.3 g/L (reference range, 6.0-15.0) and raised IgG4 levels of 3.41 g/L (reference range, 0.07-1.70). The salivary duct carcinoma contained areas of dense fibrosis and abundant IgG4-positive plasma cells (>100 per high-power field [hpf]). The adjacent noncarcinomatous areas, submandibular gland, and regional lymph nodes also contained plasma cells immunoreactive to IgG4 with densities higher than 100/hpf. To the best of our knowledge, this case is the first documentation of malignancy occurring in a background of IgG4-related autoimmune disease of the salivary gland.

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.

IgG4+ to IgG+ plasma cells ratio of ampulla can help differentiate autoimmune pancreatitis from other "mass forming" pancreatic lesions

Autoimmune pancreatitis (AIP) shows a unique spectrum of histologic features and commonly presents with an abundant IgG4-positive (IgG4+) plasma cell infiltration. However, differentiating AIP from other mass lesions, particularly pancreatic cancer [invasive ductal carcinoma (IDC)] can be clinically challenging. In this study, we evaluated the validity of IgG4 and IgG immunohistochemistry of ampullary and periampullary tissue for the diagnosis of AIP. Our study group consisted of 14 resected AIP cases with appropriate ampullary sections. Superficial ampullary tissue and "shouldering" duodenal mucosa were evaluated for several histologic variables. Immunohistochemistry for IgG4 and IgG was performed. The number of IgG4 and IgG-positive plasma cells was counted and an IgG4+ to IgG+ plasma cells ratio (IgG4/IgG ratio) was evaluated. A control cohort was composed of IDC (n=30) and chronic pancreatitis (CP) (n=29). Although an overlap was present between the groups, the overall inflammation and number of plasma cells in and around the ampulla was significantly increased in AIP compared with CP and IDC. Furthermore, although there was some overlap in the crude number of IgG4+ plasma cells of the ampullary and duodenal tissue between AIP, IDC, and CP, an IgG4/IgG ratio, especially of the ampulla, seems diagnostically useful in differentiating AIP from other "mass forming" lesions. When a cut-off of 0.10 was applied, the diagnostic sensitivity and specificity of the ampullary IgG4/IgG ratio was 86% and 95%, respectively. In conclusion, evaluation of ampullary histology and IgG4/IgG ratio might be proven beneficial in discriminating AIP from other mass forming pancreatic lesions.

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.

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.

Autoimmune pancreatitis with multifocal lesions

Two cases of a focal type of autoimmune pancreatitis (AIP) with distinct double mass lesions within the pancreas are described. In both patients, computed tomography (CT) showed localized pancreatic masses with delayed enhancement, and magnetic resonance cholangiopancreatography (MRCP) revealed localized stenoses of the main pancreatic duct (MPD) with mild upstream dilatation. Fluorodeoxyglucose positron emission tomography (FDG-PET) examination, performed in one patient, showed intense uptake concordant with tumors. Both patients received pancreatic resection with a presumptive diagnosis of pancreatic carcinoma. Histologic evaluation of the tumors showed marked lymphoplasmacytic infiltration and fibrosis around the large and medium pancreatic ducts, without any evidence of malignancy. Serum IgG4 concentration, measured postoperatively, was elevated in both patients. The characteristic morphological features of AIP are diffuse swelling of the pancreatic parenchyma and diffuse narrowing of the MPD. Recently, a focal type of AIP, which mimics pancreatic carcinoma, has been recognized. Considering the favorable response of AIP to steroid therapy, it is clinically important to differentiate the focal type of AIP from pancreatic carcinoma and to know that AIP sometimes exhibits multiple lesions within the pancreas.

Synchronous autoimmune pancreatitis and infiltrating pancreatic ductal adenocarcinoma: case report and review of the literature

An 80-year-old white man underwent pylorus-preserving pancreaticoduodenectomy after presenting with obstructive jaundice and a dilated biliary tree on cholangiopancreatography. Histologic evaluation of the specimen revealed synchronous autoimmune pancreatitis (lymphoplasmacytic sclerosing pancreatitis) and infiltrating ductal adenocarcinoma of the pancreas. The mixed inflammatory infiltrate centered on the pancreatic ducts was associated with acinar loss, parenchymal fibrosis, and obliterative venulitis. Immunohistochemical labeling with an antibody to IgG4 revealed greater than 50 IgG4-positive plasma cells per high power field. Although not appreciated grossly, pancreatic intraepithelial neoplasia-3 and a neurotropic infiltrating poorly differentiated adenocarcinoma of the pancreas were also present. This case highlights the importance of carefully evaluating patients with autoimmune pancreatitis to rule out an underlying neoplasm and the importance of following those who were treated nonsurgically until the disease fully resolves.

[Autoimmune pancreatitis]

Autoimmune pancreatitis is a rare form of chronic pancreatitis. Its clinical relevance, however, cannot be dismissed, as it can be difficult to distinguish autoimmune pancreatitis from malignant pancreatic cancer and in contrast with the majority of chronic pancreatitis forms it can be efficiently treated, even complete remission can be achieved on steroid therapy. The clinical picture of autoimmune pancreatitis is not characteristic, obstructive jaundice, abdominal pain, weight loss are frequently observed. Imaging studies often show diffuse pancreas enlargement and irregular narrowing of the main pancreatic duct. Elevated serum IgG4 immunoglobulin concentrations, some autoantibodies and the presence of IgG4 positive immune cells were observed in addition to other histological features. Apart from pancreatic manifestations, other organs may also be affected, thus associations with sclerosing cholangitis, sialoadenitis, retroperitoneal fibrosis, Riedel thyroiditis and inflammatory bowel diseases have been described. Based on these findings, autoimmune pancreatitis should be regarded as a systemic disease, as a manifestation of systemic IgG4-related sclerosing disease.

Diagnostic criteria for autoimmune pancreatitis

Autoimmune pancreatitis (AIP), a particular type of pancreatitis, is thought to have an autoimmune etiology; it is recognized as a distinct entity worldwide. AIP has many characteristic clinical, serologic, morphologic, and histopathologic features. In the absence of a diagnostic serologic marker for AIP, AIP should be diagnosed on the basis of combination of characteristic findings. AIP responds dramatically to steroid therapy; thus, accurate diagnosis of AIP can avoid unnecessary laparotomy or resection. It is important not to misdiagnose pancreatic cancer as AIP, and not to misdiagnose AIP as pancreatic cancer. Currently, 3 sets of major diagnostic criteria for AIP have been proposed in Japan, Korea, and the United States. The Japanese criteria are based on the minimum consensus features of AIP and aim to avoid misdiagnosis of malignancy. When response to steroid therapy is added to the criteria, the diagnostic sensitivity is increased. However, the use of a steroid trial in cases where differentiation from malignancy is an issue may result in delaying pancreatic cancer surgery, which could lead to cancer progression in several cases. Thus, given that AIP is an IgG4-related systemic disease, an additional criterion can be recommended to the Japanese diagnostic criteria: IgG4-immunostaining of biopsied extrapancreatic lesions such as the major duodenal papilla, the bile duct, or the minor salivary gland. It is also time for an international consensus on AIP.

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.

Serum Immunoglobulin G Fraction 4 Levels in Pancreatic Cancer: Elevations Not Associated With Autoimmune Pancreatitis

Context.—Autoimmune pancreatitis is an uncommon, inflammatory disease of the pancreas that presents with clinical features, such as painless jaundice and a pancreatic mass, similar to those caused by pancreatic cancer. Patients with autoimmune pancreatitis frequently have elevated serum immunoglobulin G fraction 4 (IgG4) levels, and their pancreatic tissue may show IgG4-positive plasma cell infiltration. It is imperative to differentiate autoimmune pancreatitis from pancreatic cancer because autoimmune pancreatitis typically responds to corticosteroid treatment. A previous Japanese study reported that serum IgG4 greater than 135 mg/dL was 97% specific and 95% sensitive in predicting autoimmune pancreatitis.

Objective.—To prospectively measure serum IgG4 levels in pancreatic cancer patients to ascertain whether increased levels might be present in this North American population.

Design.—We collected blood samples and phenotypic information on 71 consecutive pancreatic cancer patients and 103 healthy controls who visited our clinics between October 2004 and April 2006. IgG4 levels were determined using a single radial immunodiffusion assay. A serum IgG4 level greater than 135 mg/dL was considered elevated.

Results.—Five cancer patients had IgG4 elevation, with a mean serum IgG4 level of 160.8 mg/dL. None of our cancer patients with plasma IgG4 elevation demonstrated evidence of autoimmune pancreatitis. One control subject demonstrated elevated serum IgG4 unrelated to identified etiology.

Conclusions.—As many as 7% of patients with pancreatic cancer have serum IgG4 levels above 135 mg/dL. In patients with pancreatic mass lesions and suspicion of cancer, an IgG4 level measuring between 135 and 200 mg/dL should be interpreted cautiously and not accepted as diagnostic of autoimmune pancreatitis without further evaluation.

Incidence of the focal type of autoimmune pancreatitis in chronic pancreatitis suspected to be pancreatic carcinoma: experience of a single tertiary cancer center

OBJECTIVE

With an increase in autoimmune pancreatitis (AIP) being reported, the focal type of AIP, which shows localized narrowing of the main pancreatic duct and focal swelling of the pancreas, has recently been recognized. Therefore, cases of focal-type AIP subjected to surgical intervention for presumptive malignancy might previously have been diagnosed as mass-forming chronic pancreatitis. The aim of this study was to elucidate the incidence of focal-type AIP in resected chronic pancreatitis at a single tertiary cancer center. The clinical and radiological features of focal-type AIP were also evaluated.

MATERIAL AND METHODS

We re-evaluated 15 patients who underwent pancreatic resection with a presumed diagnosis of pancreatic ductal adenocarcinoma, and who in the past had been diagnosed pathologically as having chronic pancreatitis.

RESULTS

Seven of 15 patients showed AIP, and the other 8 patients were diagnosed as having mass-forming chronic pancreatitis not otherwise specified by pathological retrospective examination. In other words, nearly half of the cases of resected chronic pancreatitis that were suspected to be pancreatic carcinoma preoperatively showed focal-type AIP. Regarding the characteristic findings of focal-type AIP, narrowing of the pancreatic duct on endoscopic retrograde pancreatography (ERP) might be diagnostic.

CONCLUSIONS

Focal-type AIP is not a rare clinical entity and might be buried in previously resected pancreatic specimens that in the past were diagnosed simply as mass-forming pancreatitis.

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.

Autoimmune pancreatitis

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

Autoimmune pancreatitis: proposal of IgG4-related sclerosing disease

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