Pancreatic mass lesions associated with raised concentration of IgG4

Unique properties of IgG4 antibody and its clinical application in autoimmune pancreatitis

BACKGROUND

Autoimmune pancreatitis (AIP) is defined as a unique form of chronic pancreatitis characterized by clinical presentation with obstructive jaundice, a dense lymphoplasmacytic infiltrate and fibrosis histologically, and a dramatic response to steroids therapeutically. The possible role of IgG4 in driving the pathology of AIP is a controversial subject that has not been addressed satisfactorily.  Objective: The purpose of this review is to discuss the unique biology of IgG4 that are important for its role and the clinical applications for serologic detection.

METHODS

Review of current literature about IgG4 antibody in the clinical application in AIP.

RESULTS

High serum levels of IgG4 are an important biomarker and broadly used for diagnosis, differentiation from diseases especially pancreatic cancer, and as a parameter to indicate disease activity, extra-pancreatic lesions, and treatment monitoring. However, some controversial studies show it has a limited specificity and sensitivity in these conditions.  Conclusion: Although increasing studies have promoted our understanding of the structure and function of IgG4, there is still dilemma between the beneficial and the adverse aspect of IgG4 in the pathogenesis of AIP.

Multifocal Mass Lesions in Autoimmune Pancreatitis

A 59-year-old male patient with jaundice was referred to our hospital because of mass lesions in the pancreatic head and tail. An immunological examination revealed an elevated serum IgG4 level. Computed tomography showed two clear boundary mass lesions in the pancreatic head and tail. Magnetic resonance imaging showed that the mass lesions exhibited low intensity on T1-weighted images and iso-intensity on T2-weighted images. Magnetic resonance cholangiopancreatography showed an obstruction of the main pancreatic duct in the pancreatic head and tail. The possibility of malignant tumors could not be ruled out; therefore, we performed total pancreatectomy. A histopathological examination of the nodular lesions revealed severe lymphoplasmacytic infiltration and inflammatory change around the pancreatic ducts. Immunohistochemistry revealed diffuse infiltration of IgG4-positive plasma cells in the nodules. According to these pathological findings, we diagnosed the patient with IgG4-related multifocal mass lesions of autoimmune pancreatitis (AIP). It is difficult to distinguish between focal type AIP and pancreatic cancer. We herein report a rare case of multifocal mass lesions in AIP and include bibliographical comments.

The great imitator: IgG4 periaortitis masquerading as an acute aortic syndrome on computed tomographic angiography

We present the case of a 52-year-old woman who presented to the emergency department with chest and neck pain. Initial cervical spine magnetic resonance imaging shows an abnormal flow void in the left vertebral artery, which prompted a computed tomographic angiogram. This demonstrated a hyperdense thickened ascending aortic wall, which extended into the great vessel origins. Clinically and radiographically interpreted as an acute aortic syndrome and/or intramural hematoma, the patient underwent ascending aortic repair with graft. An unusual aortic and/or periaortic mass was encountered in surgery and final pathology demonstrated IgG4 periaortitis. A rare clinical disease, IgG4-mediated processes are often mimickers of other pathologic entities and frequently lead to misdiagnosis. All pathologically similar, IgG4-mediated disease processes can involve the pancreas, salivary glands, orbits, retroperitoneum, and the vasculature.

Difficult Diagnostic Problems in Pancreatobiliary Neoplasia

CONTEXT

Many common diagnostic dilemmas are encountered in pancreatobiliary pathology, frequently resulting in uncertainty on behalf of the pathologist and referral for a second opinion.

OBJECTIVES

To review 4 common diagnostic dilemmas encountered in the practice of pancreatobiliary pathology: (1) pancreatic ductal adenocarcinoma versus chronic pancreatitis; (2) pancreatic ductal carcinoma versus adenocarcinomas arising in the ampulla and intrapancreatic common bile duct; (3) the distinction of uncommon intraductal neoplasms--intraductal oncocytic papillary neoplasm, intraductal tubulopapillary neoplasm, and intraductal acinar cell carcinoma; and (4) intrahepatic cholangiocarcinoma versus metastatic carcinoma.

DATA SOURCES

A review of pertinent literature, along with the authors' personal experience, based on institutional and consultation materials.

CONCLUSIONS

Important diagnostic features for a few challenging problems in pancreatobiliary pathology are reviewed. Careful study of the microscopic features along with awareness of differential diagnoses and diagnostic pitfalls generally allows distinction of these entities. We also highlight established and novel ancillary studies that help to arrive at an accurate diagnosis.

Deciphering autoimmune pancreatitis, a great mimicker: case report and review of the literature

Background. Autoimmune pancreatitis (AIP) is an atypical chronic inflammatory pancreatic disease that appears to involve autoimmune mechanisms. In recent years, AIP has presented as a new clinical entity with its protean pancreaticobiliary and systemic presentations. Its unique pathology and overlap of clinical and radiological features and absence of serological markers foster the disease's unique position. We report a case of diffuse type 1 autoimmune pancreatitis with obstructive jaundice managed with biliary sphincterotomy, stent placement, and corticosteroids. A 50-year-old Caucasian woman presented to our hospital with epigastric pain, nausea, vomiting, and jaundice. Workup showed elevated liver function tests (LFT) suggestive of obstructive jaundice, MRCP done showed diffusely enlarged abnormal appearing pancreas with loss of normal lobulated contours, and IgG4 antibody level was 765 mg/dL. EUS revealed a diffusely hypoechoic and rounded pancreatic parenchyma with distal common bile duct (CBD) stricture and dilated proximal CBD and common hepatic duct (CHD). ERCP showed tight mid to distal CBD stricture that needed dilatation, sphincterotomy, and placement of stent that led to significant improvement in the symptoms and bilirubin level. Based on clinical, radiological, and immunological findings, a definitive diagnosis of AIP was made. Patient was started on prednisone 40 mg/day and she clinically responded in 4 weeks.

Recent advances in the diagnosis and management of autoimmune pancreatitis

OBJECTIVE

Autoimmune pancreatitis (AIP) is a rare chronic relapsing steroid-responsive fibroinflammatory disorder of the pancreas that is likely caused by immune dysregulation. It is now thought that AIP consists of two distinct clinicopathologic syndromes currently designated as types 1 and 2.

CONCLUSION

A current update on etiopathogenesis, pathology, and clinical and imaging findings of AIP is provided with an emphasis on diagnosis and management.

Secondary sclerosing cholangitis: pathogenesis, diagnosis, and management

Secondary sclerosing cholangitis (SSC) is an aggressive and rare disease with intricate pathogenesis and multiple causes. Understanding the specific cause underlying each case of SSC is crucial in the clinical management of the disease. Radiologic imaging can help diagnose SSC and hence institute management in a timely manner. Management may encompass simple interventions, such as supportive therapy, antibiotics, and monitoring, or more serious measures, such as surgery, endoscopic intervention, or liver transplantation. Patients with AIDS cholangiopathy have limited therapeutic options and worsened survival. The disease should always be highly suspected in patients with primary sclerosing cholangitis with questionable diagnosis.

Autoantibodies in autoimmune pancreatitis

Autoimmune pancreatitis (AIP) was first used to describe cases of pancreatitis with narrowing of the pancreatic duct, enlargement of the pancreas, hyper-γ-globulinaemia, and antinuclear antibody (ANA) positivity serologically. The main differential diagnosis, is pancreatic cancer, which can be ruled out through radiological, serological, and histological investigations. The targets of ANA in patients with autoimmune pancreatitis do not appear to be similar to those found in other rheumatological diseases, as dsDNA, SS-A, and SS-B are not frequently recognized by AIP-related ANA. Other disease-specific autoantibodies, such as, antimitochondrial, antineutrophil cytoplasmic antibodies or diabetes-specific autoantibodies are virtually absent. Further studies have focused on the identification of pancreas-specific autoantigens and reported significant reactivity to lactoferrin, carbonic anhydrase, pancreas secretory trypsin inhibitor, amylase-alpha, heat-shock protein, and plasminogen-binding protein. This paper discusses the findings of these investigations and their relevance to the diagnosis, management, and pathogenesis of autoimmune pancreatitis.

Type 1 autoimmune pancreatitis

Before the concept of autoimmune pancreatitis (AIP) was established, this form of pancreatitis had been recognized as lymphoplasmacytic sclerosing pancreatitis or non-alcoholic duct destructive chronic pancreatitis based on unique histological features. With the discovery in 2001 that serum IgG4 concentrations are specifically elevated in AIP patients, this emerging entity has been more widely accepted. Classical cases of AIP are now called type 1 as another distinct subtype (type 2 AIP) has been identified. Type 1 AIP, which accounts for 2% of chronic pancreatitis cases, predominantly affects adult males. Patients usually present with obstructive jaundice due to enlargement of the pancreatic head or thickening of the lower bile duct wall. Pancreatic cancer is the leading differential diagnosis for which serological, imaging, and histological examinations need to be considered. Serologically, an elevated level of IgG4 is the most sensitive and specific finding. Imaging features include irregular narrowing of the pancreatic duct, diffuse or focal enlargement of the pancreas, a peri-pancreatic capsule-like rim, and enhancement at the late phase of contrast-enhanced images. Biopsy or surgical specimens show diffuse lymphoplasmacytic infiltration containing many IgG4⁺ plasma cells, storiform fibrosis, and obliterative phlebitis. A dramatic response to steroid therapy is another characteristic, and serological or radiological effects are normally identified within the first 2 or 3 weeks. Type 1 AIP is estimated as a pancreatic manifestation of systemic IgG4-related disease based on the fact that synchronous or metachronous lesions can develop in multiple organs (e.g. bile duct, salivary/lacrimal glands, retroperitoneum, artery, lung, and kidney) and those lesions are histologically identical irrespective of the organ of origin. Several potential autoantigens have been identified so far. A Th2-dominant immune reaction and the activation of regulatory T-cells are assumed to be involved in the underlying immune reaction. IgG4 antibodies have two unique biological functions, Fab-arm exchange and a rheumatoid factor-like activity, both of which may play immune-defensive roles. However, the exact role of IgG4 in this disease still remains to be clarified. It seems important to recognize this unique entity given that the disease is treatable with steroids.

Mass-forming autoimmune pancreatitis and pancreatic carcinoma: differential diagnosis on the basis of computed tomography and magnetic resonance cholangiopancreatography, and diffusion-weighted imaging findings

PURPOSE

To differentiate mass-forming autoimmune pancreatitis (AIP) from pancreatic carcinoma by means of analysis of both computed tomography (CT) and magnetic resonance imaging (MRI) findings.

MATERIALS AND METHODS

Ten patients with mass-forming AIP diagnosed by revised clinical criteria of Japan Pancreas Society and 70 patients with pathologically proven pancreatic carcinoma were enrolled in this retrospective study. Two radiologists independently evaluated the CT and MR imaging findings. The sensitivity, specificity, and odds ratio of significant imaging findings and combinations of findings were calculated.

RESULTS

Seven findings were more frequently observed in AIP patients: (i) early homogeneous good enhancement, (ii) delayed homogeneous good enhancement, (iii) hypoattenuating capsule-like rim, (iv) absence of distal pancreatic atrophy, (v5) duct penetrating sign, (vi) main pancreatic duct (MPD) upstream dilatation ≤ 4 mm, and (vii) an apparent diffusion coefficient (ADC) ≤ 0.88 × 10(-3) mm(2) /s. When the findings of delayed homogeneous enhancement and ADC ≤ 0.88 × 10(-3) mm(2) /s were both used in diagnosis of mass-forming AIP, a sensitivity of 100% and a specificity of 100% were achieved. When 4 of any of the 7 findings were used in the diagnosis of AIP, a sensitivity of 100% and a specificity of 98% were achieved.

CONCLUSION

Analysis of a combination of CT and MR imaging findings allows for highly accurate differentiation between mass-forming AIP and pancreatic carcinoma.

Autoimmune pancreatitis exhibiting multiple mass lesions

Our case is a first report of autoimmune pancreatitis with multiple masses within the pancreas which was pathologically diagnosed by endoscopic ultrasound-guided fine needle aspiration and treated by steroid. The masses disappeared by steroid therapy. Our case is informative to know that autoimmune pancreatitis sometimes exhibits multiple masses within the pancreas and to diagnose it without unnecessary surgery.

Clinical significance of bile cytology via an endoscopic nasobiliary drainage tube for pathological diagnosis of malignant biliary strictures

BACKGROUND/PURPOSE

In patients in whom there is a suspicion of malignant biliary strictures, bile cytology via an endoscopic nasobiliary drainage tube (ENBD cytology) is often performed, in addition to aspirated bile cytology, brush cytology, and forceps biopsy, during the initial endoscopic retrograde cholangiopancreatography (ERCP). We aimed to reveal the significance of ENBD cytology for the pathological diagnosis of malignant biliary strictures.

METHODS

We studied 214 patients with malignant biliary strictures. We performed aspirated bile cytology, brush cytology, and forceps biopsy in 93, 130, and 114 patients, respectively. ENBD cytology was performed one or more times in 79 patients. We examined the sensitivity of each sampling method, and analyzed the utility of ENBD cytology.

RESULTS

The sensitivities of each sample acquisition method were as follows: 30% (28/93) for aspirated bile cytology, 48% (62/130) for brush cytology, 41% (47/114) for forceps biopsy, and 24% (19/79) for ENBD cytology. In 19 patients who showed positive ENBD cytology, other methods were performed in 11. Aspirated bile cytology, brush cytology, and forceps biopsy, were performed in 7, 5, and 6 patients, and the results were negative in 3 (43%), 2 (40%), and 1 (17%) patient, respectively. Three patients showed positive results only on ENBD cytology.

CONCLUSIONS

Although the sensitivity of ENBD cytology was inferior to that of the other methods used, ENBD cytology may contribute to the improvement of the total diagnostic sensitivity for malignancy.

Clinical analysis of high serum IgE in autoimmune pancreatitis

AIM: To clarify the clinical significance of high serum IgE in autoimmune pancreatitis (AIP).

METHODS: Forty-two AIP patients, whose IgE was measured before steroid treatment, were analyzed. To evaluate the relationship between IgE levels and the disease activity of AIP, we examined (1) Frequency of high IgE (> 170 IU/mL) and concomitant allergic diseases requiring treatment; (2) Correlations between IgG, IgG4, and IgE; (3) Relationship between the presence of extrapancreatic lesions and IgE; (4) Relationship between clinical relapse and IgE in patients treated with steroids, and (5) Transition of IgE before and after steroid treatment.

RESULTS: IgE was elevated in 36/42 (86%) patients. Concomitant allergic disease was observed in seven patients (allergic rhinitis in three, bronchial asthma in three, and urticaria in one). There were no significant correlations between IgG, IgG4, and IgE (r = -0.168 for IgG, and r = -0.188 for IgG4). There was no significant difference in IgE in the patients with and without extrapancreatic lesions (526 ± 531 IU/mL vs 819 ± 768 IU/mL, P = 0.163), with and without clinical relapse (457 ± 346 IU/mL vs 784 ± 786 IU/mL, P = 0.374). There was no significant difference in IgE between before and after steroid treatment (723 ± 744 IU/mL vs 673 ± 660 IU/mL, P = 0.633).

CONCLUSION: Although IgE does not necessarily reflect the disease activity, IgE might be useful for the diagnosis of AIP in an inactive stage.

The combined measurement of total serum IgG and IgG4 may increase diagnostic sensitivity for autoimmune pancreatitis without sacrificing specificity, compared with IgG4 alone

OBJECTIVES

Until now, there was no international consensus on the diagnostic criteria for autoimmune pancreatitis (AIP). As for serologic criteria, the HISORt criteria use elevated immunoglobulin (Ig) G4 alone, whereas the Asian diagnostic criteria include elevations of total IgG or IgG4, or the presence of autoantibodies. This study was mainly aimed at determining whether the combined measurement of total IgG and IgG4 could increase the diagnostic sensitivity for AIP while maintaining specificity, compared with IgG4 alone. Another aim was to determine the utility of autoantibodies to diagnose AIP.

METHODS

We prospectively measured total serum IgG and IgG4 together in 82 consecutive patients with AIP, and seropositivity was defined as elevation of either total IgG or IgG4. To evaluate specificity in the differentiation of AIP from pancreatic cancer, total serum IgG and IgG4 were prospectively measured in 110 patients with pancreatic cancer. Also, the detection rates of antinuclear antibody (ANA) and rheumatoid factor (RF) were retrospectively reviewed in patients with AIP.

RESULTS

In patients with AIP, the sensitivity of IgG4 (> or = 135 mg/dl) was 52.5% (43/82), significantly higher than that (46.3%, 38/82) of total IgG (> or = 1,800 mg/dl) (P<0.05). The sensitivity of combined measurement of total IgG and IgG4 for AIP was 68.3% (56/82), significantly higher than that of IgG4 alone (P<0.05). The specificity of total IgG and IgG4 in the differentiation of AIP from pancreatic cancer was 96.4 and 99.1%, respectively. The specificity of combined measurement of total IgG and IgG4 was 95.5%, and it was not significantly different from that of IgG4 alone (P=0.125). The sensitivity of ANA (> or = 1:80) and RF was 24.4% (19/78) and 20.3% (13/64), respectively. All but one patient who had positive results for ANA or RF also showed elevations of either total IgG or IgG4, respectively.

CONCLUSIONS

The combined measurement of total serum IgG and IgG4 may increase diagnostic sensitivity without sacrificing specificity, compared with IgG4 alone. However, the measurement of ANA or RF may show no additional benefit when combined with total serum IgG and IgG4.

Autoimmune esophagitis: IgG4-related tumors of the esophagus

We present a case of a 23-year-old gentleman who presented with dysphagia, weight loss, and recurrent esophageal strictures requiring multiple dilatations. An endoscopic ultrasound with esophagogastroduodenoscopy revealed a mass present in the distal esophagus. Fine needle aspiration suggested that the mass in the lower esophagus resembled a gastrointestinal stromal tumor. After surgical resection, final pathologic analysis revealed that the tumor was comprised of benign-appearing fibroinflammatory cells with an increase and predominance of IgG4-positive plasma cells. The microscopic appearance was consistent with a benign condition as a result of an IgG4-related process. He did not, however, have any other symptoms indicative of systemic autoimmune disease or connective tissue disorders. We present the pre-operative imaging, operative management, pathologic diagnosis, and literature review of this rare condition and the first known report of autoimmune esophagitis as part of the IgG4 spectrum of diseases.

Use of immunohistochemistry for IgG4 in the distinction of autoimmune pancreatitis from peritumoral pancreatitis

The patients with autoimmune pancreatitis usually present with jaundice and a pancreatic head mass, presumed to have pancreatic cancer, and they often undergo pancreatic resection. Elevated serum IgG4 levels (>135 mg/dL) help to distinguish autoimmune pancreatitis from pancreatic cancer. However, when the biopsy from a pancreatic mass shows dense chronic inflammation and fibrosis and the serum IgG4 level is not available, it presents a diagnostic dilemma whether it represents autoimmune pancreatitis or peritumoral pancreatitis. We performed IgG4 immunohistochemistry on 25 cases of autoimmune pancreatitis-lymphoplasmacytic sclerosing pancreatitis, 7 cases of autoimmune pancreatitis with granulocytic epithelial lesions, 8 cases of nonspecific pancreatitis, 15 cases of pancreatitis associated with pancreatic ductal adenocarcinoma, and 5 biopsies of pancreatic adenocarcinoma with variable inflammation. The distribution of IgG4-positive cells was noted in each case. Eighty-four percent (21/25) of autoimmune pancreatitis-LPSP cases showed diffuse and dense staining for IgG4, with more than 50 positive plasma cells per high-power field (range, 50-150 cells/hpf) in the highest density area. Most (5/7) cases of autoimmune pancreatitis-granulocytic epithelial lesions were negative for IgG4. Thirty-nine percent of nonspecific pancreatitis and peritumoral pancreatitis cases stained positive for IgG4, but the distribution was focal and none of the cases showed more than 50 IgG4-positive cells/hpf in the highest density area of IgG4 staining. IgG4-positive cells in peritumoral pancreatitis and nonspecific pancreatitis cases were closely associated with malignant glands and areas of acute inflammation in some cases. Using a cutoff of 50 IgG4-positive cells/hpf, the sensitivity of IgG4 staining for classical autoimmune pancreatitis-LPSP versus other types of pancreatitis was 84%, the specificity was 100%, and the P value was significant (<.0001). Hence, we conclude that diffuse and dense staining (>50 positive cells/hpf) for IgG4 is specifically seen in autoimmune pancreatitis-LPSP, and IgG4 staining along with the histologic features and serum IgG4 levels may be very helpful in diagnosing autoimmune pancreatitis.

Diagnostic utility of biopsy specimens for autoimmune pancreatitis

BACKGROUND AND AIMS

Infiltration of IgG4-positive plasma cells in the pancreas and other organs is characteristic of autoimmune pancreatitis (AIP). However, it is undetermined whether needle or forceps biopsy of pancreas or other organs is indeed useful for the diagnosis of AIP. We aimed to clarify this point.

METHODS

Among 39 AIP patients, tissue sampling without laparotomy was performed in 27. Biopsy of pancreas, gastric mucosa, liver, bile duct, and duodenal papilla was performed in 15, 17, 11, 5 and 7, respectively. The obtained specimens were examined for IgG4-positive plasma cells. We also examined gastric mucosa of 18 patients with pancreatic cancer as controls. When the number of IgG4-positive plasma cells was more than 10 per high-power field, we regarded it as diagnostic.

RESULTS

Diagnostic sensitivity in pancreas, gastric mucosa, liver, bile duct, and duodenal papilla was 47% (7/15), 47% (8/17), 36% (4/11), 0% (0/5), and 57% (4/7), respectively.

CONCLUSIONS

Sensitivity of IgG4 immunostaining was unsatisfactory when tissue sampling was performed by needle or forceps biopsy. Biopsy of gastric mucosa might be a good subsidiary diagnostic tool.

A case of IgG4-related sclerosing disease complicated by sclerosing cholangitis, retroperitoneal fibrosis and orbital pseudotumour

We present a case of IgG4-related sclerosing disease complicated by sclerosing cholangitis (SC), idiopathic retroperitoneal fibrosis (IRF) and orbital pseudotumour (OPT). Clinical, radiographic and pathological findings later suggested that the patient had SC complicated by IRF. The patient's SC and IRF were well controlled for the first 10 years of the follow-up period; OPT developed in the tenth year. During investigation of the OPT, serum IgG4 level was found to be significantly elevated. The patient was then diagnosed with IgG4-related sclerosing disease complicated by SC, IRF and OPT. This is a rare manifestation of IgG4-related sclerosing disease, which was diagnosed incidentally during OPT work-up. We suggest that this is a variation of the so-called IgG4-related sclerosing disease or hyper-IgG4 disease.

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Nonneoplastic mimickers of pancreatic neoplasms

CONTEXT

A variety of nonneoplastic conditions may form pancreatic masses that mimic carcinoma. Approximately 5% to 10% of pancreatectomies performed with the clinical diagnosis of pancreatic cancer prove on microscopic evaluation to be pseudotumors.

OBJECTIVES

To illustrate the clinical and pathologic characteristics of the 2 most frequent pseudotumoral inflammatory conditions, autoimmune pancreatitis and paraduodenal pancreatitis, and describe the criteria that may be useful in the differential diagnosis versus pancreatic carcinoma.

DATA SOURCES

Recent literature and the authors' experience with the clinical and pathologic characteristics of autoimmune pancreatitis and paraduodenal pancreatitis.

CONCLUSIONS

The knowledge of the clinical, radiologic, and pathologic findings in both autoimmune pancreatitis and paraduodenal pancreatitis is crucial in making the correct preoperative diagnosis. Autoimmune pancreatitis, which occurs in isolated or syndromic forms, is characterized by a distinctive fibroinflammatory process that can either be limited to the pancreas or extend to the biliary tree. Its correct preoperative identification on biopsy material with ancillary immunohistochemical detection of dense immunoglobulin G4-positive plasma cell infiltration is possible and crucial to prevent major surgery and to treat these patients with steroid therapy. Paraduodenal pancreatitis is a special form of chronic pancreatitis that affects young males with a history of alcohol abuse and predominantly involves the duodenal wall in the region of the minor papilla. Pathogenetically, the anatomical and/or functional obstruction of the papilla minor, resulting from an incomplete involution of the intraduodenal dorsal pancreas, associated with alcohol abuse represents the key factor. Endoscopic drainage of the papilla minor, with decompression of the intraduodenal and dorsal pancreas, might be considered in these patients.

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.

Abdominal extrapancreatic lesions associated with autoimmune pancreatitis: Radiological findings and changes after therapy

PURPOSE

To evaluate imaging findings of abdominal extrapancreatic lesions associated with autoimmune pancreatitis (AIP) and changes after steroid therapy.

METHODS AND MATERIALS

This study included nine AIP patients with abdominal extrapancreatic lesions, which were determined by retrospective radiological review. CT (initial and follow-up, n=9) and MR imaging (initial, n=5) were reviewed by two radiologists in consensus to determine imaging characteristics (i.e., size, number, attenuation or signal intensity, and contrast enhancement of the lesions, and the presence of overlying capsule retraction) and evaluate changes with steroid therapy of abdominal extrapancreatic lesions associated with AIP.

RESULTS

The most common abdominal extrapancreatic lesion associated with AIP was retroperitoneal fibrosis (RPF) in six patients. In five patients, CT and MR imaging revealed single or multiple, round- or wedge-shaped, hypoattenuating or hypointense, enhancing lesions in the renal cortex or pelvis. Other lesions included a geographic, ill-defined, hypoattenuating lesion with or without overlying capsule retraction in the liver in two and bile duct dilatation with or without bile duct wall thickening in four. Over a follow-up period of 6-81 months, CT exams of eight patients demonstrated partial or complete improvement of the abdominal extrapancreatic lesions, albeit their improvement in general lagged behind that of the pancreatic lesion.

CONCLUSION

On CT or MR imaging, the abdominal extrapancreatic lesions associated with AIP are various in the retroperitoneum, liver, kidneys and bile ducts, and are reversible with steroid therapy.

Isolated Lymphoplasmacytic Sclerosing Pancreatitis Involving the Pancreatic Tail

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

Autoimmune pancreatitis

Autoimmune pancreatitis is the pancreatic manifestation of a systemic disorder that affects various organs, including the bile duct, retroperitoneum, kidney, and parotid and lacrimal glands. It represents a recently described subset of chronic pancreatitis that is immune mediated and has unique histologic, morphologic, and clinical characteristics. A hallmark of the disease is its rapid response to corticosteroid treatment. Although still a rare disease, autoimmune pancreatitis is increasingly becoming recognized clinically, leading to evolution in the understanding of its prognosis, clinical characteristics, and treatment.

IgG4-related sclerosing lymphoplasmacytic pancreatitis and cholangitis mimicking carcinoma of pancreas and Klatskin tumour

BACKGROUND

Autoimmune sclerosing pancreatitis is a well-known disease entity for years, particularly recognizing the difficulty in distinguishing it from malignancy. Immunohistochemical study showed that immunoglobulin IgG4 staining was positive in plasma cells of some autoimmune pancreatitis or cholangitis. The term 'autoimmune sclerosing pancreatocholangitis' was used as it was believed that they belonged to a range of disease involving both pancreas and biliary tree. It may also be part of a systemic fibro-inflammatory disease.

PATIENTS AND METHODS

All the patients suffering from immunoglobulin G4 (IgG4)-related pancreatitis and cholangitis from May 2003 to September 2006 in Queen Elizabeth Hospital, Hong Kong were retrospectively studied.

RESULTS

A total of five patients with clinical diagnosis of IgG4-related autoimmune pancreatitis or cholangitis were analysed. All presented with jaundice or abdominal pain, mimicking carcinoma. Two patients had major resection, two patients were diagnosed by intraoperative biopsy and one was based on serum IgG4 level.

CONCLUSION

With the growing awareness of this relatively recently characterized clinical entity and its similar presentation to pancreatic carcinoma or bile duct cholangiocarcinoma, it is important for autoimmune sclerosing pancreatocholangitis to be included in the differential diagnosis of pancreaticobiliary disease. The management strategy has shown to be modified--from major resection to intraoperative biopsy and to the assay of serum IgG4 level without the necessity of histology confirmation.

Acute recurrent pancreatitis: An autoimmune disease?

In this review article, we will briefly describe the main characteristics of autoimmune pancreatitis and then we will concentrate on our aim, namely, evaluating the clinical characteristics of patients having recurrence of pain from the disease. In fact, the open question is to evaluate the possible presence of autoimmune pancreatitis in patients with an undefined etiology of acute pancreatitis and for this reason we carried out a search in the literature in order to explore this issue. In cases of recurrent attacks of pain in patients with “diopathic”pancreatitis, we need to keep in mind the possibility that our patients may have autoimmune pancreatitis. Even though the frequency of this disease seems to be quite low, we believe that in the future, by increasing our knowledge on the subject, we will be able to diagnose an ever-increasing number of patients having acute recurrence of pain from autoimmune pancreatitis.

Diagnostic approach to patients with acute idiopathic and recurrent pancreatitis, what should be done?

Acute recurrent pancreatitis (ARP) is a common clinical condition that may be difficult to diagnose. Endoscopic ultrasound (EUS) is proposed to be a safe first line test of choice in the majority of patients. When interventions are needed to remove biliary stones, evaluate sphincter of Oddi or pancreas divisum, endoscopic retrograde cholangiopancreatography (ERCP) is recommended. Magnetic resonance cholangiopancreatography (MRCP) can be a suitable alternative from a diagnostic standpoint although may not be widely available. Finally, genetic testing is increasingly used to detect certain mutations that are associated with this diagnosis.

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.

The sensitivity and specificity of serum immunoglobulin G and immunoglobulin G4 levels in the diagnosis of autoimmune chronic pancreatitis: Korean experience

OBJECTIVES

Serum immunoglobulin G (IgG) and/or IgG4 elevation is one of the notable characteristics of autoimmune chronic pancreatitis (AIP). The purpose of this study was to compare the sensitivity and specificity of IgG with those of IgG4 in the diagnosis of AIP.

METHODS

From December 2005 to March 2006, patients who were diagnosed as having ordinary chronic pancreatitis of a certain cause (n = 67) and pancreatic cancer (n = 76) in Asan Medical Center were enrolled. The IgG and IgG4 levels of these patients were compared with those of 35 AIP patients diagnosed in Asan Medical Center.

RESULTS

The percentage of patients with serum IgG level more than 1800 mg/dL was 10.4% (7/67), 2.6% (2/76), and 54.3% (19/35) in patients with ordinary chronic pancreatitis, pancreatic cancer, and AIP, respectively. As for serum IgG4 levels more than 135 mg/dL, it was 11.9% (8/67), 1.3% (1/76), and 73.3% (22/30), respectively. The specificity of IgG at 1800 mg/dL and IgG4 at 135 mg/dL was both 93.7%. The serum IgG4 showed high specificity (98.7%) in differentiating AIP from pancreatic cancer. The IgG4 level at 141 mg/dL was determined as the most optimal cutoff value with resulting sensitivity and specificity of 73.3% and 95.1%, respectively (area under the curve, 0.816), whereas for IgG, it was determined as 1770 mg/dL, with sensitivity and specificity of 57.1% and 93.7% (area under the curve, 0.788).

CONCLUSIONS

The sensitivity of serum IgG4 tended to be higher than that of IgG in the diagnosis of AIP. The IgG4 showed high specificity in the differential diagnosis of AIP from pancreatic cancer. Serum IgG4 should be included in the diagnostic workup for AIP.

Value of serum IgG4 in the diagnosis of autoimmune pancreatitis and in distinguishing it from pancreatic cancer

OBJECTIVES

To determine the sensitivity and specificity of elevated serum IgG4 level for the diagnosis of autoimmune pancreatitis (AIP) and its ability to distinguish AIP from pancreatic cancer, its main differential diagnosis.

METHODS

We measured serum IgG4 levels (normal 8-140 mg/dL) in 510 patients including 45 with AIP, 135 with pancreatic cancer, 62 with no pancreatic disease, and 268 with other pancreatic diseases.

RESULTS

Sensitivity, specificity, and positive predictive values for elevated serum IgG4 (>140 mg/dL) for diagnosis of AIP were 76%, 93%, and 36%, respectively, and 53%, 99%, and 75%, respectively, for IgG4 of >280 mg/dL. Among subjects with elevated IgG4, non-AIP subjects (N = 32) differed from AIP subjects (N = 34) in that they were more likely to be female (45%vs 9%, P < 0.001), less likely to have serum IgG4 >280 mg/dL (13%vs 71%, P < 0.001), or elevation of total IgG (16%vs 56%, P < 0.001). Serum IgG4 levels were elevated in 13/135 (10%) pancreatic cancer patients; however, only 1% had IgG4 levels >280 mg/dL compared with 53% of AIP. Compared with AIP, pancreatic cancer patients were more likely to have CA19-9 levels of >100 U/mL (71%vs 9%, P < 0.001).

CONCLUSION

Elevated serum IgG4 levels are characteristic of AIP. However, mild (<2-fold) elevations in serum IgG4 are seen in up to 10% of subjects without AIP including pancreatic cancer and cannot be used alone to distinguish AIP from pancreatic cancer. Because AIP is uncommon, IgG4 elevations in patients with low pretest probability of having AIP are likely to represent false positives.

Autoimmune pancreatitis with multifocal mass lesions

Autoimmune pancreatitis (AIP) is radiologically characterized as diffuse swelling of the pancreatic parenchyma and irregular narrowing of the pancreatic ducts. We present a case of AIP with multiple small nodular lesions in the pancreas. This case suggests that AIP with only small nodular or localized lesions is more difficult to differentiate from pancreatic cancer than typical cases of AIP.

Advances in autoimmune pancreatitis

Autoimmune Pancreatitis (AIP) is a special kind of chronic pancreatitis, and its essential quality remains unclear. At present, deeper researches showed that AIP was different from other pancreatitis, and had a variety of clinical features. Therefore, it was attracting more and more attention as an independent disease. In this article, we summarized the advances in the pathogenic mechanisms, clinical symptoms, diagnosis and treatment of autoimmune pancreatitis in the past few years.

Autoimmune Pancreatitis: Frequency, IgG4 Expression, and Clonality of T and B Cells

Autoimmune pancreatitis (AIP) is a newly recognized disease. The presence of IgG4 positive plasma cells is thought to be of diagnostic help. In a surgical series of chronic pancreatitis cases, we determined the relative frequency of AIP before and after 1990, analyzed the diagnostic significance of IgG4 expression and examined the presence of oligoclonal T or B-cell populations. The histopathology of 202 surgical specimens of chronic pancreatitis removed between 1975 and 2004 was reviewed and 2 groups were distinguished, 1 of AIP cases and the other of nonautoimmune chronic pancreatitis (non-AIP CP). The intensity of infiltration of pancreatic tissue by IgG4 positive plasma cells and other immune cells was studied immunohistochemically. Finally, T and B-cell clonality was tested by polymerase chain reaction-based analysis. Except for 1 case in 1978, all cases of AIP were observed after 1990. IgG4 positive plasma cells were detected in 72.5% of AIP cases and in 63.1% of non-AIP CP cases. More than 20 cells per high power field were only seen in AIP (sensitivity 43%, specificity 100%). This finding was associated with higher age and grade. Polyclonal T and B-cell populations were found in both AIP and non-AIP CP except for 1 AIP case showing an oligoclonal IgGH-FR3 gene rearrangement. AIP seems to have increased considerably in frequency in the last 2 decades. High density infiltrates of IgG4 positive plasma cells are diagnostic for AIP, but are seen in less than half of the cases. T or B-cell oligoclonality could not be established as a feature of AIP.

Chronic pancreatitis, pseudotumors and other tumor-like lesions

Chronic pancreatitis is a fibroinflammatory disease of the pancreas. Etiologically, most cases are related to alcohol abuse and smoking. Recently, gene mutations have been identified as the cause of hereditary pancreatitis. Other chronic pancreatitis types that were defined in recent years are autoimmune pancreatitis (lymphoplasmacytic sclerosing pancreatitis) and paraduodenal pancreatitis ('groove pancreatitis', 'cystic dystrophy of heterotopic pancreas'). This review describes and discusses the main histological findings, the pathogenesis and the clinical features of the various types of chronic pancreatitis. In addition, pseudotumors and other tumor-like lesions are briefly mentioned.

Autoimmune pancreatitis: a systemic immune complex mediated disease

Autoimmune pancreatitis (AIP) is a mass forming inflammatory pancreatobiliary-centric disease. Recent reports of multiorgan inflammatory mass forming lesions with increased numbers of IgG4 positive plasma cells suggest that AIP may have a systemic component. In this study, we explore the systemic nature of AIP, investigate the relevance of subtyping AIP, perform a systematic study of tissue IgG4 immunoperoxidase, and ultrastructurally evaluate the presence of immune complexes. Our study group consisted of 36 patients with AIP, 21 of whom underwent a Whipple procedure. On the basis of the pattern of inflammation, pancreatic involvement was subtyped as ductocentric (AIP-D) or lobulocentric (AIP-L). Extrapancreatic lesions included bile duct (n=3), salivary glands (n=3), lung (n=2), gallbladder (n=11), and kidney (n=4). Clinical and radiologic data was recorded. Immunohistochemistry for IgG4 was performed on both pancreatic and extrapancreatic tissues and the numbers of IgG4 positive plasma cells were semiquantitatively scored. A control cohort composed of pancreatic adenocarcinoma (n=19) and chronic pancreatitis-not otherwise specified (NOS) (n=14) was also evaluated. Eleven pancreatic specimens, including 2 cases of chronic pancreatitis-NOS and 4 kidneys were evaluated ultrastructurally. The pancreas, bile duct, gall bladder, salivary gland, kidney, and lung lesions were characterized by dense lymphoplasmacytic infiltrates with reactive fibroblasts and venulitis. IgG4 positive plasma cells were identified in all pancreatic and extrapancreatic lesions. The AIP cases showed significantly more pancreatic IgG4 positive plasma cells than chronic pancreatitis-NOS or adenocarcinoma (P=0.001). However, IgG4 positive cells were identified in 57.1% of chronic pancreatitis-NOS and 47.4% of ductal adenocarcinoma. Fifteen of 21 resected cases were classified as AIP-D, and 6 as AIP-L, the latter notably showing significantly more IgG4 positive plasma cells than the former (P=0.02). Additionally, clinical and radiologic differences emerged between the 2 groups. Ultrastructurally, electron dense deposits of immune complexes were identified in the basement membranes of 7 of the 9 AIP cases and in 3 of the 4 renal biopsies evaluated. AIP represents the pancreatic manifestation of a systemic autoimmune disease. Clinical and immunologic findings justify the recognition of pancreatic lobulocentric and ductocentric subtypes. Documentation of increased numbers of tissue IgG4 positive plasma cells, although not an entirely specific marker for AIP, may provide ancillary evidence for the diagnosis of a IgG4-related systemic disease.

Difficulty in diagnosing autoimmune pancreatitis by imaging findings

BACKGROUND

Autoimmune pancreatitis (AIP) presents as diffuse enlargement of the pancreas and as diffuse irregular narrowing of the main pancreatic duct. However, some AIP cases are difficult to diagnose because of atypical imaging findings.

OBJECTIVE

To clarify a variety of imaging findings of AIP and the reason for its misdiagnosis.

DESIGN

We examined the imaging findings of 37 AIP cases and also examined misdiagnosed cases of AIP to determine their reasons for misdiagnosis.

PATIENTS

A total of 37 patients with AIP who reported to our hospital or its affiliate over a 17-year period (1989 to May 2005).

RESULTS

Patients in 15 AIP cases showed segmental narrowing of the main pancreatic duct. There were 6 patients with focal enlargement of the pancreas, whereas 3 patients showed no enlargement. There were 3 cases of calcification of the pancreas. Pancreatic cysts were detected in 2 patients. Abdominal US showed multiple low-echoic masses in 1 case and a single mass in 3 cases. Sixteen patients had stenosis of the bile duct at the hilar hepatic lesion and/or the intrahepatic duct. Only 7 patients had typical AIP findings. Six patients were misdiagnosed with pancreatic cancer and 2 with bile-duct cancer. Seven cases were surgically treated. Five cases were misdiagnosed because of the nonexistence of, or the unfamiliarity with, the concept of AIP and sclerosing cholangitis with AIP. Another 3 cases were diagnosed with pancreatic cancer because of segmental stenosis of the main pancreatic duct and no or focal enlargement of the pancreas.

CONCLUSIONS

The results of this study suggest that AIP presents a variety of imaging findings. The most important diagnostic factor is clinician awareness of the concept of AIP and the diverse nature of imaging findings.

The relationship of salivary gland function to elevated serum IgG4 in autoimmune pancreatitis

OBJECTIVE

To compare salivary gland function in autoimmune pancreatitis (AIP) patients with and without an elevated serum IgG4 concentration.

PATIENTS AND METHODS

We allocated 14 AIP patients into 2 groups: one group had high (>135 mg/dL) serum IgG4 and the other low serum IgG4. Sialochemistry and submandibular and parotid gland scintigraphy were done in these patients.

RESULTS

Serum IgG4 levels were elevated in 10 patients. Bilateral submandibular gland swelling was present in 5 patients with a high serum IgG4; there was no swelling in patients with a low serum IgG4. The salivary Na+ concentration was increased significantly in both patient groups (p<0.01) compared to controls. The beta2-microglobulin concentration was significantly higher in patients with a high serum IgG4 than in those with a low serum IgG4 (p<0.05) and controls (p<0.01). On submandibular and parotid gland scintigraphy, both the ratio of the cumulative peak count to the injected radionuclide (PCR) and the washout ratio (WR) were significantly lower in the high serum IgG4 group than in controls (p<0.01). In the low serum IgG4 group, the PCR on submandibular gland scintigraphy, and the PCR and WR on parotid gland scintigraphy were significantly lower than in controls (p<0.05, p<0.01 and p<0.05, respectively). On submandibular gland scintigraphy, the PCR was significantly lower in the high serum IgG4 group than in the low serum IgG4 group (p<0.05).

CONCLUSIONS

Salivary gland function was impaired in all AIP patients, but it was more impaired in patients with a high serum IgG4 than in those with a low serum IgG4.

Nephropathy in IgG4-related Systemic Disease

Lymphoplasmacytic sclerosing pancreatitis ("autoimmune" pancreatitis) is the best-known manifestation of an unusual corticosteroid-sensitive systemic fibrosclerotic disease that is associated with high plasma immunoglobulin G4 (IgG4) and tissue infiltration with IgG4-secreting plasma cells. Pancreatic and biliary manifestations of this condition are well-reported, but reports of other systemic involvement are few. We report here a case of initially unrecognized autoimmune pancreatitis followed 5 years later by a focal sclerosing lymphoplasmacytic tubulointerstitial nephritis and concurrent membranous nephropathy. The patient presented with hypertension, a raised serum creatinine, proteinuria, elevated serum IgG4, and eosinophilia. Immunolabeling of renal tissue showed numerous IgG4 positive plasma cells with peritubular and glomerular subepithelial IgG4 deposition. On steroid therapy serum IgG4 levels normalized, the eosinophilia resolved, and there was improvement in symptomatic wheeze, dry eyes, serum creatinine, and liver function tests. This case highlights a distinctive and potentially treatable form of interstitial nephritis manifesting from a systemic immune disorder, and provides circumstantial evidence to support the notion that dysregulated IgG4 can precipitate the development of a form of membranous nephropathy.

Sclerosing cholangitis: a focus on secondary causes

Secondary sclerosing cholangitis (SSC) is a disease that is morphologically similar to primary sclerosing cholangitis (PSC) but that originates from a known pathological process. Its clinical and cholangiographic features may mimic PSC, yet its natural history may be more favorable if recognition is prompt and appropriate therapy is introduced. Thus, the diagnosis of PSC requires the exclusion of secondary causes of sclerosing cholangitis and recognition of associated conditions that may potentially imitate its classic cholangiographic features. Well-described causes of SSC include intraductal stone disease, surgical or blunt abdominal trauma, intra-arterial chemotherapy, and recurrent pancreatitis. However, a wide variety of other associations have been reported recently, including autoimmune pancreatitis, portal biliopathy, eosinophillic and/or mast cell cholangitis, hepatic inflammatory pseudotumor, recurrent pyogenic cholangitis, primary immune deficiency, and AIDS-related cholangiopathy. This article offers a comprehensive review of SSC.

Pancreatic cancer with a high serum IgG4 concentration

Differentiation between autoimmune pancreatitis and pancreatic cancer is sometimes difficult. It has been reported that serum IgG4 concentrations are significantly elevated and particularly high (>135 mg/dL) in autoimmune pancreatitis. Measurement of serum IgG4 has become a useful tool for differentiating between autoimmune pancreatitis and pancreatic cancer. However, we present a 74-year-old female with a markedly elevated serum IgG4 (433 mg/dL) who underwent pancreaticoduodenectomy for pancreatic cancer. Elevated serum IgG4 levels continued after the resection. On histology, adenocarcinoma of the pancreas accompanied with moderate lymphoplasmacytic infiltration infiltrated the lower bile duct and duodenum, but there were no findings of autoimmune pancreatitis. Although a small metastasis was detected in one parapancreatic lymph node, regional lymph nodes were swollen. Abundant IgG4-positive plasma cells infiltrated the cancerous areas of the pancreas, but only a few IgG4-positive plasma cells were detected in the noncancerous areas. Pancreatic cancer cells were not immunoreactive for IgG4. An abundant infiltration of IgG4-positive plasma cells was detected in the swollen regional lymph nodes and in the duodenal mucosa. We believe that the serum IgG4 level was elevated in this patient with pancreatic cancer as the result of an IgG4-related systemic disease that had no clinical manifestations other than lymphadenopathy.

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.

Recurrence of inflammatory pseudotumor in the distal bile duct: Lessons learned from a single case and reported cases

Inflammatory myofibroblastic tumors (IMTs) or inflammatory pseudotumors (IPs) have been extensively discussed in the literature. They are usually found in the lung and upper respiratory tract. However, reporting of cases involving the biliopancreatic region has increased over recent years. Immunohistochemical study of these lesions limited to the pancreatic head or distal bile duct seems to be compatible with those observed in a new entity called autoimmune pancreatitis, but usually intense fibrotic reaction (zonation) predominates producing a mass. When this condition is limited to the pancreatic head, the common bile duct might be involved by the inflammatory process and jaundice may occur often resembling adenocarcinoma of the pancreas. We have previously reported a case of IMT arising from the bile duct associated with autoimmune pancreatitis which is an extremely rare entity. Four years after Kaush-Whipple resection, radiological examination on routine follow-up revealed a tumor mass, suggesting local recurrence. Ultrasound-guided FNA confirmed our suspicious diagnosis. This present case, as others, suggests that persistent follow-up is necessary in order to prevent irreversible liver damage at this specific location.

High-rate pulmonary involvement in autoimmune pancreatitis

Autoimmune pancreatitis (AIP) has extrapancreatic complications such as Sjögren's syndrome, retroperitoneal fibrosis and sclerosing cholangitis. We studied 30 patients with AIP. Of these, we identified pulmonary involvement in four patients during follow up. Among them, two patients had respiratory failure. They showed good response to steroid therapy, but a higher dose of prednisolone was necessary to maintain remission than that required in biliary involvement. Elevation of immunoglobulin G(4) and Krebs von den Lungen-6 levels were characteristic of pulmonary involvement. They may be useful for early detection of pulmonary complication.

Serum IgG4 concentrations in pancreatic and biliary diseases

BACKGROUND

Recently, it has been reported that the serum concentration of IgG4, a minor component of IgG subclasses, is increased in autoimmune pancreatitis. However, data regarding IgG4 concentrations in other pancreatic or biliary diseases have been insufficient.

METHODS

Serum IgG4 was measured in 116 patients with pancreatic or biliary diseases (35 autoimmune pancreatitis, 24 chronic pancreatitis except autoimmune pancreatitis, 11 primary sclerosing cholangitis, 23 pancreatic cancer, 3 islet cell tumor, 2 papilla cancer, 15 bile duct cancer, and 3 gallbladder cancer patients). The cut-off concentration of IgG4 was 135 mg/dl.

RESULTS

Increased serum IgG4 was observed in 33 of 35 patients with autoimmune pancreatitis, 0 of 24 with chronic pancreatitis, 4 of 11 with primary sclerosing cholangitis, 0 of 23 with pancreatic cancer, 0 of 3 with islet cell tumor, 0 of 2 with duodenal papilla cancer, 0 of 15 with bile duct cancer and 0 of 3 with gallbladder cancer patients.

CONCLUSIONS

Serum IgG4 was increased in autoimmune pancreatitis and was within normal limits for other pancreatic or biliary diseases except primary sclerosing cholangitis.

Chronic pancreatitis

PURPOSE OF REVIEW

As in our previous reviews, we endeavor to review important new observations in chronic pancreatitis made in the past year. We included articles, including review articles, only if they contained new observations or readdressed old questions and provided new insights into old and new concepts.

RECENT FINDINGS

Important observations include the following: (1) Strong association between cystic fibrosis transmembrane regulator dysfunction/mutations and 'recurrent acute pancreatitis', particularly in patients with pancreas divisum (2) Pancreas divisum may be incidental finding in recurrent acute pancreatitis (3) Smoking increases risk of chronic pancreatitis (4) Coxsackie B virus may increase severity of alcoholic chronic pancreatitis (5) CD4+ T cells and an immune reaction against amylase may play a role in pathogenesis of autoimmune pancreatitis (6) 2-(18F)-Fluro-2-deoxy-D-glucose positron emission tomography might be useful to detect pancreatic cancer in chronic pancreatitis patients at risk for developing pancreatic cancer, but contrast-enhanced Doppler ultrasound or endosonography may be as sensitive and better than contrast enhanced computed tomography (7) Superiority of surgery vs endotherapy for long term pain relief and weight gain in painful chronic pancreatitis (8) Early treatment of pain and malabsorption may improve life quality (9) Antifibrogenesis and fibrolytic agents as potential therapies.

SUMMARY

Ongoing basic and clinical research this past year has further characterized genetic, molecular and clinical aspects of chronic pancreatitis. The advent of predictable and lasting treatments of chronic pancreatitis is most likely to appear on the wings of carefully conducted studies targeting genetic and molecular mechanisms of chronic pancreatitis, particularly pancreatic fibrogenesis.