自身免疫性胰腺炎误诊误治17例临床分析

Objective To summarize the reasons of mis-diagnosis and mis-treatment of autoimmune pancreatitis (AIP). Methods Clinical data of 17 patients with AIP,who were admitted to the hospital from May 2005 to July 2010 and experienced mis-diagnosis and mis-treatment, were retrospectively analyzed. Results The main clinical manifestations included epigastric pain (13 cases),progressive obstructive jaundice (12 cases), fever (6 cases) and weight loss (9 cases). Fifteen patients had extrapancreatic organ involvemnet, including allergic rhinitis, swelling of lymphoglandulae submaxillares, swelling of submaxillary gland, allergic asthma, rheumatoid arthritis, Sjogren syndrome, diabetes mellitus, primary sclerosing cholangitis and autoimmune hepatitis. Of these 17 cases, 11 cases presented with high serum globulin, 14 cases with high serum IgG, 13 cases with high serum γ-globulin, 13 cases with positive anti-nuclear antibody and 2 cases with positive anti-insulin IgG antibody. The abdominal imaging demonstrated that 15 patients had diffuse enlargement of the pancreas with diffuse or segmental narrowing of main pancreatic duct, narrowing of the intrapancreatic common bile duct, dilation of the proximal biliary duct and gallbladder enlargement. Focal enlargement of the pancreas was found in 2 cases. Thirteen cases were misdiagnosed as pancreatic carcinoma. Among them, 4 cases underwent pancreaticoduodenectomy and 7 cases underwent choledochojejunostomy. Two cases were misdiagnosed as end stage of cancer that lost therapeutic chance. Another 4 cases were misdiagnosed as chronic pancreatitis. Steroid therapy was administered in all patients with satisfactory response. All patients were followed-up for 15 months (ranged from 6 months to 45 months), and recurrence was found in 4 cases. Satisfactory response was found in patients treated with steroid for the second time. No pancreatic cancer was found in these patients in the follow up period. Conclusion The main causes of mis-diagnosis and mis-treatment of AIP may be contributed by difficulty in differentiating AIP from pancreatic carcinoma based on clinical manifestations and inadequate knowledge of AIP as well as insufficient attention to AIP in China.     

自身免疫性胰腺炎误诊误治17例临床分析

Objective To summarize the reasons of mis-diagnosis and mis-treatment of autoimmune pancreatitis (AIP). Methods Clinical data of 17 patients with AIP,who were admitted to the hospital from May 2005 to July 2010 and experienced mis-diagnosis and mis-treatment, were retrospectively analyzed. Results The main clinical manifestations included epigastric pain (13 cases),progressive obstructive jaundice (12 cases), fever (6 cases) and weight loss (9 cases). Fifteen patients had extrapancreatic organ involvemnet, including allergic rhinitis, swelling of lymphoglandulae submaxillares, swelling of submaxillary gland, allergic asthma, rheumatoid arthritis, Sjogren syndrome, diabetes mellitus, primary sclerosing cholangitis and autoimmune hepatitis. Of these 17 cases, 11 cases presented with high serum globulin, 14 cases with high serum IgG, 13 cases with high serum γ-globulin, 13 cases with positive anti-nuclear antibody and 2 cases with positive anti-insulin IgG antibody. The abdominal imaging demonstrated that 15 patients had diffuse enlargement of the pancreas with diffuse or segmental narrowing of main pancreatic duct, narrowing of the intrapancreatic common bile duct, dilation of the proximal biliary duct and gallbladder enlargement. Focal enlargement of the pancreas was found in 2 cases. Thirteen cases were misdiagnosed as pancreatic carcinoma. Among them, 4 cases underwent pancreaticoduodenectomy and 7 cases underwent choledochojejunostomy. Two cases were misdiagnosed as end stage of cancer that lost therapeutic chance. Another 4 cases were misdiagnosed as chronic pancreatitis. Steroid therapy was administered in all patients with satisfactory response. All patients were followed-up for 15 months (ranged from 6 months to 45 months), and recurrence was found in 4 cases. Satisfactory response was found in patients treated with steroid for the second time. No pancreatic cancer was found in these patients in the follow up period. Conclusion The main causes of mis-diagnosis and mis-treatment of AIP may be contributed by difficulty in differentiating AIP from pancreatic carcinoma based on clinical manifestations and inadequate knowledge of AIP as well as insufficient attention to AIP in China.     

Tuberculosis of pancreas and peripancreatic lymph nodes in immunocompetent patients： experience from China

AIM: To determine the clinical, radiographic and laboratory characteristics, diagnostic methods, and therapeutic variables in immunocompetent patients with tuberculosis (TB) of the pancreas and peripancreatic lymph nodes. METHODS: The records of 16 patients (6 male, 10 female;mean age 37 years, range 18-56years) with tuberculosis of the pancreas and peripancreatic lymph nodes from 1983 to 2001 in the Southwest Hospital were analyzed retrospectively.In addition, 58 similar cases published in Chinese literature were reviewed and summarized. We reviewed the clinical,radiographic and laboratory findings, diagnostic methods,therapeutic approaches, and outcome in the patients. Criteria for the diagnosis of pancreatic tuberculosis were the presence of granuloma in histological sections or the presence of Mycobacterium tuberculosis DNA by polymerase chain reaction (PCR). RESULTS: Predominant symptoms consisted of abdominal nodule and pain (75 ％), anorexia/weight loss (69 ％),malaise/weakness (64 ％), fever and night sweats (50 ％),back pain (38 ％) and jaundice (31％). Swelling of the head of the pancreas with heterogeneous attenuation echo was detected with ultrasound in 75 ％ (12/16). CT scan showed pancreatic mass with heterogeneous hypodensity focus in all patients, with calcification in 56 ％ (9/16) patients, and peripancreatic nodules in 38 ％ (6/16)patients. Anemia and lymphocytopenia were seen in 50 ％(8/16) patients, and pancytopenia occurred in 13 ％ (2/16) patients. Hypertransaminasemia, elevated alkaline phosphatase (AP) and GGT were seen in 56 ％ (9/16)patients. The erythrocyte sedimentation rate (ESR) was elevated in 69 ％ (11/16) cases. Granulomas were found in 75 ％ (12/16) cases, and in 38 ％ (6/16) cases caseous necrosis tissue was found. Laparotomy was performed in 75 ％ (12/16) cases, and ultrasound-guided fine needle aspiration (FNA) was done in 63 ％ (10 of 16). The most commonly used combinations of medications were isoniazid/rifampin/streptomycin (63 ％, n=10) and isoniazid/rifampin pyrazinamide/streptomycin or ethambutol (38 ％, n=6). The duration of treatment lasted for half or one year and treatment was successful in all cases. The characteristics of 58 cases from Chinese literature were also summarized. CONCLUSION: Tuberculosis of the pancreas and peripancreatic lymph nodes should be considered as a diagnostic possibility in patients presenting with a pancreatic mass, and diagnosis without laparotomy is possible if only doctors are aware of its clinical features and investigate it with appropriate modalities. Pancreatic tuberculosis can be effectively cured by antituberculous drugs.     

PRSS1_p.Leu81Met mutation results in autoimmune pancreatitis

AIM: To describe protease serine 1 (PRSS1) gene mutations in patients with autoimmune pancreatitis (AIP) and the clinical features of AIP. METHODS: Fourteen patients with AIP, 56 with other chronic pancreatitis, 254 with pancreatic cancer and 120 normal controls were studied. The mutations and polymorphisms of four genes involved with pancreatitis or pancreatic cancer, PRSS1 , SPINK1 , CFTR and MEN1 , were sequenced. The pathogenic mechanism of AIP was investigated by comparing the wild-type expression system with the p.81Leu→Met mutant expression system. RESULTS: Two novel mutations (p.81Leu→Met and p.91Ala→Ala) were found in PRSS1 gene from four patients with AIP. PRSS1_p.81Leu→Met mutation led to a trypsin display reduction (76.2%) combined with phenyl agarose (Ca2+ induced failure). Moreover, the ratio of trypsin/amylase in patients with AIP was higher than in the patients with pancreatic cancer and other pancreatitis. A large number of lymphocytes and plasma cells were found in the bile ducts accompanied by hyperplasia of myofibroblasts. CONCLUSION: Autoimmune pancreatitis may be related to PRSS1 gene mutations.     

Retrospective study of steroid therapy for patients with autoimmune pancreatitis in a Chinese population

AIM:To explore the optimal steroid therapeutic strategy for autoimmune pancreatitis(AIP).METHODS:This study was conducted retrospectively in two large institutions in China.Patients with clinically,radiologically and biochemically diagnosed AIP were enrolled.The performed radiological investigations and biochemical tests,the regimen of the given steroid treatment,remission and relapse whether with and without steroid therapy were analyzed.RESULTS:Twenty-eight patients with AIP received steroid treatment,while 40 patients were treated surgically by pancreatoduodenectomy,distal pancreatectomy and choledochojejunostomy,radiofrequency ablation for the enlarged pancreatic head,percutaneous transhepatic biliary drainage and endoscopic biliary drainage.The starting oral prednisolone dose was 30 mg/d in 18(64.3%) patients and 40 mg/d in 10(35.7%) patients administered for 3 wk.The remission rate of AIP patients with steroid treatment(96.4%) was significantly higher than in those without steroid treatment(75%).Maintenance therapy(oral prednisolone dose 5 mg/d) was performed after remission for at least 6-12 mo to complete the treatment course.Similarly,the relapse rate was significantly lower in AIP patients with steroid treatment(28.6%) than in those without steroid treatment(42.5%).Steroid re-treatment was effective in all relapsed patients with or without steroid therapy.CONCLUSION:Steroid therapy should be considered in all patients with active inflammatory phase of AIP.However,the optimal regimen still should be trailed in larger numbers of patients with AIP.     

MRCP and MRI findings in 9 patients with autoimmune pancreatitis

AIM: To evaluate magnetic resonance cholangiopancre-atography (MRCP) findings in conjunction with magnetic resonance (MR) images in autoimmune pancreatitis (AIP) patients. METHODS: Nine patients with AIP underwent MRI, MRCP, endoscopic retrograde cholangiopancreatography (ERCP), computed tomography, and ultrasonography. The MRCP and MR images taken before and after steroid therapy were reviewed and compared with other imaging modalities. The MRCP findings of the AIP cases were compared to those of 10 cases with carcinoma of the head of the pancreas. RESULTS: On MRCP, the narrowed portion of the main pancreatic duct noted on ERCP was not visualized, while the non-involved segments of the main pancreatic duct were visualized. The degree of upstream dilatation of the proximal main pancreatic duct was milder than that seen in cases of pancreatic carcinoma. Stenosis or obstruction of the lower bile duct was detected in 8 patients. MR images showed enlargement of the pancreas with decreased signal intensity on T1-weighted MR images, increased signal intensity on T2-weighted MR images, and, in 3 patients, a hypointense capsule-like rim. After steroid therapy, the previously not visualized portion of the main pancreatic duct was seen, along with improvement of the bile duct stenosis. Pancreatic enlargement decreased, and the abnormal signal intensity on both T1- and T2-weighted MR images became isointense. CONCLUSION: MRCP cannot differentiate irregular narrowing of the main pancreatic duct seen with AIP from stenosis of the main pancreatic duct seen with pancreatic carcinoma. However, MRCP findings in conjunction with MR imaging of pancreatic enlargement that shows abnormal signal intensity on T1- and T2-weighted MR images are useful in supporting a diagnosis of AIP.     

A variant form of autoimmune pancreatitis successfully treated by steroid therapy, accompanied by von Meyenburg complex

Diagnostic criteria for autoimmune pancreatitis （AIP） have been proposed and used clinically because, despite its unique clinicopathological features, AIP does not have disease-specific serological tests for confirmation. However, diagnosis of a patient with pancreatic lesions mimicking cancer who deviates from these diagnostic criteria is still difficult. We present herein a patient with a variant form of AIP successfully diagnosed by fine-needle biopsy, whose response to steroid therapy was excellent. A 55-year-old Japanese man was admitted to hospital because of jaundice and pancreatic head mass. AIP was considered as one of the differential diagnoses; however, as the patient showed neither pancreatic duct narrowing nor immunological abnormalities, he did not meet the Japanese diagnostic criteria for AIP. Histopathology of the pancreatic mass demonstrated abundant infiltration by lymphocytes and interstitial fibrosis, which suggested AIP. Immunoreaction to IgG4, which is supposed to be specific to AIP, was not observed; however, response to subsequent prednisolone therapy was good, with dramatic pancreatic head mass regression. Aside from the pancreatic head mass, diffusely spreading small lesions were observed throughout the liver. The likelihood of a potential association with extrapancreatic lesions of AIP was considered and led us to carry out a liver biopsy, which revealed biliary hamartoma, also called yon Meyenburg complex （VMC）. As IgG4-positive plasma cell infiltration was not demonstrated in the hamartomatous regions, the hepatic condition was thought to have occurred incidentally; however, to the best of our knowledge, this is the first report in which the association between AIP and VMC was investigated and discussed.     

Sclerosing cholangitis associated with autoimmune pancreatitis differs from primary sclerosing cholangitis

AIM： To clarify the characteristic features of biliary lesions in patients with autoimmune pancreatitis （AIP） and compare them with those of primary sclerosing cholangitis （PSC）.METHODS： The clinicopathological characteristics of 34 patients with sclerosing cholangitis （SC） associated with AIP were compared with those of 4 patients with PSC.RESULTS： SC with AIP occurred predominantly in elderly men. Obstructive jaundice was the most frequent initial symptom in SC with AIP. Only SC patients with AIP had elevated serum IgG4 levels, and sclerosing diseases were more frequent in these patients. SC patients with AIP responded well to steroid therapy. Segmental stenosis of the lower bile duct was observed only in SC patients with AIP, but a beaded and prunedtree appearance was detected only in PSC patients.Dense infiltration of IgG4-positive plasma cells was detected in the bile duct wall and the periportal area, as well as in the pancreas, of SC patients with AIP.CONCLUSION： SC with AIP is distinctly different from PSC. The two diseases can be discriminated based on cholangiopancreatographic findings and serum IgG4 levels.     

Diagnostic criteria for autoimmune pancreatitis in Japan

Autoimmune pancreatitis （AIP） is a particular type of pancreatitis of presumed autoimmune etiology. Currently, AIP should be diagnosed based on combination of clinical, serological, morphological, and histopathological features. When diagnosing AIP, it is most important to differentiate it from pancreatic cancer. Diagnostic criteria for AIP, proposed by the Japan Pancreas Society in 2002 first in the world, were revised in 2006. The criteria are based on the minimum consensus of AIP and aim to avoid misdiagnosing pancreatic cancer as far as possible, but not for screening AIR The criteria consist of the following radiological, serological, and histopathological items： （1） radiological imaging showing narrowing of the main pancreatic duct and enlargement of the pancreas, which are characteristic of the disease; （2） laboratory data showing abnormally elevated levels of serum y-globulin, IgG or IgG4, or the presence of autoantibodies; （3） histopathological examination of the pancreas demonstrating marked fibrosis and prominent infiltration of lymphocytes and plasma cells, which is called lymphoplasmacytic sclerosing pancreatitis （LPSP）. For a diagnosis of AIP, criterion 1 must be present, together with criterion 2 and/ or criterion 3. However, it is necessary to exclude malignant diseases such as pancreatic or biliary cancer.     

New tumor-associated antigen SC6 in pancreatic cancer

AIM: To examine the concentration of a new antigen SC6 (SC6-Ag) recognized by monoclonal antibody (MAb) in patients with pancreatic cancer and other malignant or benign diseases and to understand whether SC6-Ag has any clinical significance in distinguishing pancreatic cancer from other gastrointestinal diseases. METHODS: Six hundred and ninety-five serum specimens obtained from 115 patients with pancreatic cancer, 154 patients with digestive cancer and 95 patients with non-digestive cancer were used and classified in this study. Serum specimens obtained from 140 patients with benign digestive disease and 89 patients with non-benign digestive disease served as controls. Ascites was tapped from 16 pancreatic cancer patients, 19 hepatic cancer patients, 16 colonic cancer patients, 10 gastric cancer and 6 severe necrotic pancreatitis patients. The samples were quantitated by solid-phase radioimmunoassay. The cut-off values (CV) of 41, 80, and 118 U/mL were used. RESULTS: The average intra- and interassay CV detected by immunoradiometric assay of SC6-Ag was 5.4% and 8.7%, respectively. The sensitivity and specificity were 73.0% and 90.9% respectively. The levels in most malignant and benign cases were within the normal upper limit. Among the 16 pancreatic cancer cases, the concentration of SC6-Ag in ascites was over the normal range in 93.8% patients. There was no significant difference in the concentration of SC6-Ag. Decreased expression of SC6-Ag in sera was significantly related to tumor differentiation. The concentration of SC6-Ag was higher in patients before surgery than after surgery. The specificity of SC6-Ag and CA19-9 was significantly higher than that of ultrasound and computer tomography (CT) in pancreatic cancer patients. Higher positive predictive values were indicated in 92.3% SC6-Ag and 88.5% CA19-9, but lower in 73.8% ultrasound and 76.2% CT. CONCLUSION: The combined test of SC6-Ag and CA19-9 may improve the diagnostic rate of primary cancer. The detection of SC6-Ag is valuable in the diagnosis of pancreatic cancer before and after surgery.     

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.     

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.     

Strategy to differentiate autoimmune pancreatitis from pancreas cancer

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

Clinical difficulties in the differentiation of autoimmune pancreatitis and pancreatic carcinoma

OBJECTIVES: Autoimmune pancreatitis (AIP) is a newly described entity with characteristic clinical, histologic, and morphologic changes, in which autoimmune mechanisms are involved in pathogenesis. However, difficulties can arise in the differentiation of AIP from pancreatic carcinoma. The aims of this study were to clarify clinical and radiologic features of AIP to elucidate areas of diagnostic confusion. METHODS: Clinical, serologic, and radiologic findings were evaluated in 17 patients with AIP. RESULTS: All 17 patients were initially suspected to have pancreatic carcinoma. The patients were predominantly elderly men who frequently presented with jaundice but without features of acute pancreatitis. Elevation of serum gamma-globulin and IgG along with the presence of autoantibodies were usually evident, whereas serum tumor markers were elevated in 54% of cases. Stenosis of the bile duct was detected in 94% of cases. Diffuse enlargement of the pancreas and irregular narrowing of the main pancreatic duct were radiologically characteristic; however, segmental swelling and narrowing were detected in seven and two patients, respectively. In segmental cases, neither atrophy of the distal pancreas nor marked upstream dilation of the distal main pancreatic duct was observed.Angiographic abnormalities occurred in 54% of cases. Serologic and radiologic abnormalities showed considerable improvement with steroid therapy. CONCLUSIONS: Frequent stenosis of the bile duct, elevation of serum tumor markers, segmental pancreatic enlargement or narrowing of the main pancreatic duct, and angiographic abnormalities can cause confusion in the differential diagnosis of AIP and pancreatic carcinoma.     

Autoimmunpankreatitis – „the new kid on the block“

Autoimmune pancreatitis (AIP) is a rare form of chronic pancreatitis which is characterized by diffuse or focal pancreatic enlargement, a lymphoplasmacytic infiltrate with a storiform fibrosis and a dramatic response to steroid treatment. AIP can be classified into three subtypes: lymphoplasmacytic sclerosing pancreatitis (LPSP; AIP type 1), idiopathic duct centric pancreatitis (IDCP; AIP type 2), and not otherwise specified (NOS). AIP type 1 is the pancreatic manifestation of IgG4-related disease which also involves other organs; AIP type 2 is a pancreas-specific, IgG4-negative disorder and is associated with inflammatory bowel disease. Epidemiological studies from Japan estimate an incidence of approximately 0.82 per 100,000 inhabitants; in Europe 5–6% of all patients with chronic pancreatitis are diagnosed with AIP. The pathomechanism of AIP remains enigmatic, but a mulitfactorial etiology with genetic predisposition and environmental influences has been proposed. Clinically, patients can present with jaundice, epigastric pain, weight loss and new-onset diabetes, thus, raising suspicion for pancreatic malignancy. A combination of the HISORt (Histology, Imaging, IgG4 Serology, other Organ involvement and Response to steroid therapy) criteria can be used to definitively diagnose AIP in most cases. The greatest challenge is to differentiate AIP from pancreatic cancer and cholangiocarcinoma, since it often presents with a pancreatic mass, lymphadenopathy and bile duct obstruction. The prognosis of AIP is usually favorable; in over 90% of cases remission can be induced by steroid treatment.     

Diagnosis of autoimmune pancreatitis: the Mayo Clinic experience.

BACKGROUND & AIMS: The Japan Pancreas Society criteria for diagnosis of autoimmune pancreatitis (AIP) mandate presence of characteristic imaging (diffuse pancreatic enlargement with diffusely irregular, narrow pancreatic duct). AIP has unique histologic features associated with infiltration of tissues of affected organs with abundant IgG4-positive cells. We propose expanded diagnostic criteria for AIP with a cohort of histologically confirmed AIP. METHODS: We reviewed the pancreatic imaging findings on computed tomography scans, serum IgG4 levels, other organ involvement, and response to steroids in 29 consecutive patients who met histologic criteria for AIP. RESULTS: Computed tomography scans (n = 22) showed diffuse pancreatic enlargement in 6 (27%) patients; the rest had focal enlargement, distinct mass, normal pancreas, or focal acute pancreatitis. Serum IgG4 level was elevated in 15 of 21 (71%) patients, and other organ involvement (eg, intrahepatic biliary strictures) was noted in 11 of 29 (38%) patients. All 17 patients treated with steroids exhibited resolution/marked improvement of pancreatic/extrapancreatic manifestation. On the basis of this experience we propose that diagnosis of AIP can be made in patients with > or =1 of these criteria: (1) diagnostic histology, (2) characteristic imaging on computed tomography and pancreatography with elevated serum IgG4 level, or (3) response to steroid therapy of pancreatic/extrapancreatic manifestations of AIP. Twenty additional patients met expanded diagnostic criteria for AIP, and their demographic and clinical profile was similar to that of the 29 patients meeting histologic criteria. CONCLUSIONS: AIP defined by histological criteria shows a wide spectrum of radiologic features, with characteristic imaging seen only in a minority. Incorporation of additional features into current diagnostic criteria can identify the full spectrum of clinical presentations of AIP.     

Diagnosis of autoimmune pancreatitis using endoscopic ultrasonography

Background  Revised clinical criteria for autoimmune pancreatitis (AIP) have been proposed by the Research Committee of Intractable Disease of the Pancreas and the Japan Pancreas Society. These criteria require distinguishing AIP from neoplastic lesions. However, this can be difficult, and patients often undergo surgery on the basis of suspected pancreatic cancer (PC). Methods  AIP was diagnosed in 25 patients at the Aichi Cancer Center Hospital (ACCH) according to the revised AIP criteria. In each patient, endoscopic ultrasonography (EUS) was used to describe the conventional pancreatic parenchymal and ductal features of chronic pancreatitis (Sahai criteria), and other abnormal features, namely, diffuse hypoechoic areas (DHAs), diffuse enlargement (DE), focal hypoechoic areas (FHAs), focal enlargement, bile duct wall thickening (BWT), lymphadenopathy, and peripancreatic hypoechoic margins (PHMs). We compared these features between 25 patients with AIP and 30 patients with pancreatic cancer resected at ACCH. Results  Few conventional EUS features of chronic pancreatitis (CP) were seen in patients with AIP (mean, 2.0 features). Frequencies of DHA, DE, BWT, and PHM were significantly higher in AIP than in PC. DHAs, DE, and FHAs resolved after steroid treatment. Conclusions  Novel EUS features of AIP are useful in distinguishing AIP from PC and for following the effects of steroid therapy.     

Autoimmune pancreatitis mimicking pancreatic cancer

Background/purpose

Autoimmune pancreatitis (AIP) is a form of chronic pancreatitis that can often be difficult to distinguish from pancreatic cancer. We describe the clinical and radiographic features of 23 patients with AIP whose presentations mimicked pancreatic cancer.

Methods

A review of clinic, radiology, and endoscopy records from a 6-year period identified patients with AIP initially suspected of having pancreatic cancer. Abdominal computed tomography (CT) with intravenous contrast, endoscopic ultrasonography (EUS), and/or ERCP was performed in each patient. The diagnosis of AIP was made histologically and/or cytologically for each patient.

Results

Nineteen of 23 patients (83%) presented with new-onset weight loss, jaundice, or both. Nineteen (83%) patients had CT findings worrisome for pancreatic cancer including: (1) pancreatic enlargement or focal mass, (2) regional lymphadenopathy, and/or (3) vascular invasion. Eighteen patients (78%) had common bile duct strictures on ERCP. EUS-guided fine-needle aspiration biopsies excluded pancreatic cancer in all 22 patients who had EUS (96%). Seven patients had surgery for continued suspicion of pancreatic cancer.

Conclusions

Although AIP commonly presents with features suggestive of pancreatic cancer, clinical recognition of AIP with appropriate diagnostic testing including EUS with fine-needle aspiration, ERCP, IgG4 levels, and pancreatic protocol CT expedites diagnosis and can spare patients unnecessary surgery.     

Autoimmunpankreatitis

Autoimmune pancreatitis (AIP) has been established for more than 15?years as a disease entity of chronic pancreatitis. Although the autoimmune etiology is well established AIP is still an enigmatic disease. Morphological hallmarks of the disease are narrowing of the pancreatic duct system and frequently even narrowing of the bile duct by periductal lymphoplasmocytic inflammation. In cases of more localized inflammation obstructive jaundice due to a mass-forming lesion in the pancreatic head may mimic pancreatic ductal adenocarcinoma. Therefore, even in tertiary referral center, AIP patients underwent pancreatic surgery for suspected pancreatic cancer due to misclassification. Histopathologically, the disease can be differentiated into lymphoplasmacytic sclerosing pancreatitis (LPSP) with IgG4-positive cells or idiopathic ductocentral chronic pancreatitis (IDCP) with granulocyte epithelial lesions and eosinophils. Recently, LPSP has been coined AIP type 1 and IDCP as AIP type 2 following a recent consensus conference. Serologically, patients may present with elevated serum IgG and IgG4 levels. Additionally, autoantibodies have been described targeting ductal and acinar antigens. Association with other autoimmune manifestations in a wide range of organs is relatively frequent. In most cases, autoimmune pancreatitis responds to steroid treatment very quickly, which is of specific importance when considering the differential diagnosis of pancreatic cancer.     

Mass‐forming type 1 autoimmune pancreatitis mimicking pancreatic cancer

We reported three cases of mass‐forming type 1 autoimmune pancreatitis (AIP) that were preoperatively suspected to be pancreatic cancer, and reviewed their clinicopathological features. Radiological findings in the patients revealed hypoattenuating masses in the early phase or a stricture of the main pancreatic duct with upstream dilatation, which was consistent with the diagnosis of pancreatic cancer. Histopathologically, the lesions were well demarcated and met all diagnostic criteria for immunoglobulin G4 (IgG4)‐related AIP, including the presence of periductal lymphoplasmacytic infiltration, obliterative phlebitis, storiform fibrosis and abundant IgG4‐positive plasma cells. However, the adjacent uninvolved pancreatic duct and lobular structures were well preserved. And in all patients, none or some of the aforementioned characteristics were observed. We suggest that some cases of focal AIP may progress to more severe grades and exhibit mass formation, although remaining localized. These focal cases of AIP are difficult to distinguish from pancreatic cancer. To our knowledge, this report is the first to present a histopathological comparison of mass‐forming AIP with the adjacent uninvolved pancreatic tissues.