Pancreatic reconstruction is defined as the construction of an outflow channel for pancreatic juice by pancreaticoenterostomy or pancreaticopancreaticostomy following complete separation of the pancreatic parenchyma or pancreatic duct. Surgical procedures that require pancreatic reconstruction include pancreatic head resection and middle pancreatectomy, which involve pancreatic resection, and pancreas head-preserving segmental duodenectomy and partial resection of the papilla of Vater, which do not involve pancreatic resection. In most cases undergoing these procedures, pancreatic reconstruction is accomplished by pancreaticojejunostomy or pancreaticogastrostomy, but reconstruction by pancreaticoduodenostomy or pancreatic duct-to-duct anastomosis is possible depending on the length of the resected pancreas or the diameter of the pancreatic duct. The General Rules for the Study of Pancreatic Cancer in Japan, 5th Edition, provide detailed descriptions of the reconstruction methods after pancreaticoduodenectomy (PD) or pylorus-preserving PD, but there is no mention of reconstruction methods following other resection procedures. Therefore, the authors hope that the concept and terms concerning these methods be discussed and clarified in the future.

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Diagnostic criteria for autoimmune pancreatitis (AIP) were first proposed by the Japan Pancreas Society in 2002 and revised by the Research Committee of Intractable Diseases of the Pancreas provided by the Ministry of Health, Labour and Welfare of Japan in 2006. Diagnostic criteria for AIP in Japan consist of pancreatic images, serologic tests, and pancreatic histology, whereas diagnostic criteria proposed by the United States, Korea and Italy include the responsiveness to steroid as a diagnostic criterion for AIP. Since the most important point in the diagnosis of AIP is not to misdiagnose pancreatic carcinoma as AIP, the diagnostic criteria for AIP require greater specificity than sensitivity. Therapeutic diagnosis by steroid may increase the sensitivity, but there is a possibility of lowering the specificity. AIP may present characteristic findings of chronic pancreatitis in the natural course or after steroid therapy. Therefore, several diagnostic criteria depending on the clinical stage or an evaluation method by a scoring system might be required to diagnose different stages of AIP. In addition, it is important to distinguish patients with AIP who will progress to chronic pancreatitis from those who will not progress to chronic pancreatitis.

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Currently in Japan, the diagnosis of autoimmune pancreatitis (AIP) is based on the"Clinical diagnostic criteria 2006 of AIP"proposed by the Japan Pancreas Society (JPS) and the Research Committee of Intractable Diseases of the Pancreas (RCIDP) supported by the Japanese Ministry of Health, Labor, and Welfare, which is a revised version of"the diagnostic criteria 2002 of AIP, proposed by JPS in 2002". Since 2002, the accumulation of many AIP cases has shown a slight change in the concept of AIP, including extra-pancreatic lesions and associated disorders, which suggests that the current diagnostic criteria are becoming inadequate.
In 2003, the RCIDP began to review the current diagnostic criteria based on recently-acquired information and knowledge. The team organized a working group, consisting of the team members and researchers specializing in AIP, to develop a proposal for the revision of the current diagnostic criteria. On October 7, 2005 and April 22, 2006, the RCIDP and the JPS jointly held open forums to discuss the proposed amendment.
This report describes the background of the proposed amendment and the finalized proposal of the revised version as the clinical diagnostic criteria of AIP 2006.

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US, CT and MRI findings of autoimmune pancreatitis (AIP) were described based on "Clinical diagnostic criteria of autoimmune pancreatitis 2006". Evaluation of the enlargement of the pancreas, either diffuse or localized, is the essential point by imaging studies. However, other characteristic imaging findings are also required in order to obtain a correct diagnosis. On US, hypoechoic pancreatic enlargement is characteristic to AIP. On dynamic study, either on CT or on MRI, AIP usually shows a delayed enhancement pattern. Signal intensity on T1-weighted MRI usually decreased, however it varies on T2-weighted image. Attention should be paid to the fact that there are various imaging findings of AIP, probably due to the disease condition. At present, MRCP cannot be used in evaluating main pancreatic duct narrowing; however, it might be used in the near feature based on advances in image quality.

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The diagnosis of autoimmune pancreatitis (AIP) requires confirmation of diffuse or segmental narrowing of the main pancreatic duct with an irregular wall. Pancreatic duct narrowing is usually diagnosed by images of the pancreatic duct on endoscopic retrograde cholangiopancreatography. The pancreatic duct is considered to be narrowed if the diameter of the main pancreatic duct is smaller (narrower) than the normal portion of the duct and shows an irregular wall. Unlike obstruction or stricture, narrowing of the pancreatic duct extends over a larger range. In typical cases, more than one-third of the total length of the pancreatic duct is narrowed. Even in cases where the narrowing is focal and extends to less than one-third of the total length, the diagnosis of AIP is possible if the other clinical criteria are satisfied. In some patients, it is difficult to differentiate between irregular narrowing of the pancreatic duct in AIP and stricture of the pancreatic duct in pancreatic cancer when affected the pancreatic duct is focal.

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IgG4 measurement was adopted in the new version of Japanese diagnostic criteria for autoimmune pancreatitis proposed in 2006. The sensitivity and specificity of IgG4 for the diagnosis of autoimmune pancreatitis were 80% and 98%. However, IgG4 is not pathognomonic, because a high serum IgG4 concentration was also associated with a few cases of pancreatic cancer. The sensitivity and specificity of IgG were 80% and 98%, respectively. Sensitivities of disease non-specific autoantibodies of anti-nuclear antigen (ANA) and rheumatoid factor (RF) were 60% and 20%∼30%, respectively. Disease specific autoantibodies of anti-SSA, anti-SSB and anti-mitochondrial antibody showed negative results. A comparative study using identical sera showed the best diagnostic result for IgG4. Additional measurements of ANA and RF further improved the results of IgG4, though combined measurement of IgG4 and IgG showed no advantage. Because IgG4 measurement in Japan is costly, it would be useful to measure IgG combined with ANA and RF for the diagnosis of autoimmune pancreatitis.

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The "clinical diagnostic criteria of autoimmune pancreatitis: revised proposal, 2006" are, (1) histological diagnosis with a tiny biopsy specimen and (2) no use of special stains other than routine ones. The histology of autoimmune pancreatitis in Japan corresponds to so-called "lymphoplasmacytic sclerosing pancreatitis": periductal lymphoplasmacytic infiltration, inter/intra lobular fibrosis (storiform fibrosis), IgG4-positive plasma cells (IgG-P), and obliterative phlebitis.
The diagnostic criteria of autoimmune pancreatitis in Mayo Clinic are different from ours in that immunostaining for IgG4 is often required as well as a larger biopsy specimen. Korean criteria are similar to ours, but the biopsy procedures are different. A big challenge for pancreatic biopsy must be how to get a diagnostic, representative specimen of the entire histology. Many IgG4-Ps in storiform fibrosis are "diagnostic" and even a tiny specimen can be diagnostic if it includes an adequate amount of lesion.

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We report herein the results from the nationwide survey for autoimmune pancreatitis (AIP) in 2002. The number of patients with AIP who visited hospitals was approximately 900 (95% confidence interval; range 670-1,100), suggesting a prevalence of AIP in the Japanese population of 0.71 per 100,000. The disease-onset age in approximately half of the patients (45%) was 61-70 years. The male: female ratio was 2.77:1. On pancreatic imaging studies, 42% of the patients showed both diffuse narrowing of the main pancreatic duct and diffuse swelling of the pancreas. In serological studies, an increased serum IgG4 level (more than 135mg/dl) showed the highest sensitivity for the diagnosis (83%). Stricture of the distal common bile duct was observed in almost all of the patients but stricture of the extra-pancreatic bile ducts was seen in approximately 10% of the patients. Other extra-pancreatic complications included salivary gland lesions (9.4%), retroperitoneal fibrosis (7.3%), chronic thyroiditis (2.6%), interstitial nephritis (1%), and interstitial pneumonia (1%). Although pancreatectomy was performed in 22% of the patients until 2001, approximately 90% of the patients were treated with steroid since 2002.

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Autoimmune pancreatitis (AIP) is often associated with various systemic extrapancreatic lesions. Some of these systemic extrapancreatic lesions show similar pathological findings to those in the pancreas. In order to make a precise diagnosis of AIP in difficult cases, we should refer to extra-pancreatic lesions such as sclerosing cholangitis, sclerosing sialadenitis, and retroperitoneal fibrosis.
Cases of AIP with systemic extrapancreatic lesions exhibit higher levels of γ-globulins, IgG, and IgG4, all of which are considered hallmarks of autoimmune abnormality. Such patients also require maintenance steroid therapy.
In our immunohistochemical study, the normal epithelia of the pancreatic ducts, bile ducts, gallbladder and salivary gland ducts reacting with the patients sera were detectable by the anti-IgG4 antibody. Therefore, the serum of AIP patients may contain an IgG4 auto-antibody to various organs. These results support the concept of multifocal fibrosclerosis or IgG4-related autoimmune diseases, of which pancreatic lesions are manifestations.

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Autoimmune pancreatitis (AIP) can be defined as a rare chronic inflammation of the pancreas due to an autoimmune mechanism. Corticosteroid treatment and the long-term prognosis (outcome) of AIP are still controversial. In Japan, the initial corticosteroid dosage has been 30 to 40mg per day and tapered during one to two months, based on changes in clinical symptoms, laboratory data and abdominal imaging of the pancreas and bile duct. Recently, cases of malignancies including pancreatic cancer have been reported during the course of AIP. However, the carcinogenesis of AIP is not understood. Further studies are necessary to clarify the initial corticosteroid dosage (30mg or 40mg) and the period of maintenance treatment as well as the long-term outcome of AIP. Furthermore, the natural history of AIP needs to be more clearly elucidated.

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Autoimmune pancreatitis in foreign countries is described. Histopathological findings of autoimmune pancreatitis in Japan is marked lymphoplasmacytic infiltration with fibrosis in the pancreas (lymphoplasmacytic sclerosing pancreatitis). However, autoimmune pancreatitis with neutrophilic infiltration in the epithelium of the pancreatic duct was reported by American and Italian pathologists. These patients showed different clinicopathological features from autoimmune pancreatitis defined in Japan as follows: no prediction for elderly males, frequent association with inflammatory bowel disease, and weaker association with other sclerosing diseases.
In 2006, the Japanese clinical diagnostic criteria of autoimmune pancreatitis were revised, and diagnostic criteria of autoimmune pancreatitis were proposed in Korea and USA. The Korean and American criteria, in addition to the Japanese criteria, include the response to steroid therapy and the presence of extrapancreatic lesions. It is necessary to reach an international consensus on autoimmune pancreatitis.

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Autoimmune pancreatitis (AIP) is an emerging disease whose concept was first proposed in our country and its recognition has spread rapidly world-wide. On the other hand, the disease concept itself is still fluid and has been changing recently; it is known to be characterized by massive infiltration of IgG4 positive plasma cells into the pancreas, an elevation of serum IgG4 and the involvement of various extrapancreatic organs. There are many issues to be clarified in the pathogenesis and pathophysiology, but the following items can be listed as requiring especially urgent agreement: 1) Where should AIP be placed in the concept of chronic pancreatitis? 2) Is AIP a homogeneous disease both pathologically and clinically? 3) Should diagnostic use of steroids be allowed? These items are major factors that might cause confusion in clinical practice, and therefore require an international consensus.

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Chronic pancreatitis with pancreatolithiasis is a disease with progressive exocrine and endocrine insufficiency that requires treatment for relapsing intractable abdominal pain. The efficacy and result of ESWL treatment for 22 patients with symptomatic pancreatolithiasis were examined for a mean follow up period of 3 years. The successful rates of fragmentation of pancreatic stones, complete removal of stones and pain relief were 95.5%, 50% and 95.5% of the patients, respectively. Complete removal in those with pancreatic stones was significantly difficult in patients with main pancreatic duct strictures and multiple stones. ESWL related complications were observed in two patients: acute cholecystitis and acute pancreatitis, but they recovered with conservative treatment. Neither pancreatic exocrine nor endocrine functions improved after ESWL. After complete removal of stones in 11 patients, recurrence of stones and pain were not observed. Even in incompletely removed cases, 8 of 10 patients had no pain. The results suggest that ESWL is effective for fragmentation of pancreatic stones and pain relief for patients with pancreatolithiasis.

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A 42-year-old man with alcoholic chronic pancreatitis was admitted complaining of hematoemesis.
Emergency endoscopic examination revealed much coagulated blood in the stomach, but we could not find bleeding spots and the bleeding had stopped. Computed tomography demonstrated massive blood in the stomach and also a pancreatic pseudocyst containing blood. Furthermore, there was an aneurysm of the left gastric artery in the pancreatic pseudocyst. It was suspected that this aneurysm had perforated to the pancreatic pseudocyst, resulting in penetration to the weak portion of the stomach around the lesion the drainage of the pseudocyst via the gastric posterior portion which was done at a previously visited hospital.
The patient underwent embolization by microcapusule, histoacryllipiodol and distal pancreatectomy. Chronic pancreatitis complicated by vascular aneurysms of the small artery is not so rare, but only nine cases of a rupture of an aneurysm of the left gastric artery have been reported in Japan.

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An 82-years-old man was admitted to our hospital because of nausea and upper abdominal pain. He had undergone partial gastrectomy with Billroth-II reconstruction for gastric cancer. Abdominal CT scan showed a markedly dilated duodenum located behind the superior mesenteric artery. Therefore, we diagnosed the patient as severe acute pancreatitis due to afferent loop obstruction. After percutaneus drainage of the dilated duodenum, the acute pancreatitis was significantly improved. We conclude that decompression of a dilated duodenum would be a usefull treatment for patients with acute pancreatitis due to afferent loop obstruction.

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A female in her 70s was admitted to our hospital because of fever, upper abdominal pain and general fatigue. Transabdominal ultrasonography and CT showed a 90-mm solid tumor in the head of the pancreas and some metastatic liver tumors. The biopsy specimens obtained by EUS-FNA revealed aggregation of atypical lymphocytes. Histologically, the tumor was diagnosed as large B cell lymphoma according to several immunohistochemical stainings. After 3 months of chemotherapy, the primary and metastatic tumors had disappeared showing complete remission. This patient has no recurrence for over 2 years.

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A 75-year-old man was admitted to our hospital because of a pancreatic tumor detected by ultrasonography. He had undergone right nephrectomy for renal cell carcinoma (RCC) 8 years ago. Dynamic CT and angiography showed a hypervascular mass in the pancreas head. Based on the diagnosis of pancreatic metastasis from RCC, pancreatoduodenectomy was performed. Histological examination of the specimen revealed a metastatic tumor from RCC. In this case, he had been examined by conventional enhanced CT two months before, but the pancreatic metastatic tumor could not be detected because this tumor was too small and was isodense even after enhancement. In conclusion, careful follow-up by ultrasonography and dynamic CT is necessary for the early detection of pancreatic metastasis from RCC.

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