[in Japanese]

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[in Japanese]

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Acute pancreatitis has been considered to be an auto-digestive phenomenon resulting from the inappropriate activation of digestive enzymes within the pancreas itself. However, acute pancreatitis has many clinical aspects concerning not only auto-digestion, but also a large number of sequelae including edema, coagulation and vascular complications, infiltration of immune cells, and local and systemic inflammation. Accumulating evidence using genetic mouse models (e.g. cathepsin B KO mice, conditional transgenic mice of rat trypsinogen II, and trypsinogen 7 KO mice) suggest that active trypsin is but one component of the multifaceted response of acinar cells to injury, and that multiple pathways are activated simultaneously by various etiologies that cause pancreatitis. Interferon regulatory factor 2 (IRF2) KO mice presented an early feature of acute pancreatitis. In the acinar cells of this mouse model, pancreatic regulated exocytosis was inhibited due to the alteration of SNARE proteins, resulting in the increase of autophagy and intracellular trypsinogen activation. Clarifying the molecular mechanisms by which IRF2 regulates the exocytotic machinery and the turbulence of signaling pathways in IRF2 KO acinar cells will make it possible to elucidate the molecular basis of acute pancreatitis and the initial trigger that causes premature activation of trypsinogen.

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The significance of endoscopic treatment in improvement of nutritional status in patients with chronic pancreatitis (CP) was investigated. The nutritional status during endoscopic stenting of 19 patients with CP, who required continual pancreatic drainage by the stenting for more than 12 months, were examined retrospectively by BMI, serum albumin levels, total lymphocyte count, Prognostic Nutritional Index (PNI), and total cholesterol levels. Nutritional status significantly improved in 12 patients after the stent treatment, whereas the status did not improve in 7 patients who had suffered from acute relapse of CP after the stenting. Significant improvement of serum albumin levels, total lymphocyte count, and PNI was found at 1-3 months while that of BMI was achieved at 7-9 months after the stenting. In short, nutritional improvement was achieved within 10 months after the beginning of the endoscopic treatment only in patients that did not suffer a symptomatic attack. From a nutritional improvement standpoint, short period endoscopic treatment preceding surgery is a valuable strategy for the treatment of CP which may in turn reduce the risk of surgical complications.

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Radiological findings of autoimmune pancreatitis (AIP) are sometimes similar to those of pancreatic cancer (PC). The aim of this study was to clarify the utility of perfusion computed tomography (CT) for the differential diagnosis of AIP from PC. Perfusion CT was performed in 12 patients with AIP and 22 patients with PC. All AIP patients were diagnosed as type 1. Parameters including pancreatic volumetric blood flow F_V, volume of distribution V_D and blood perfusion pattern R² were determined from a single-compartment kinetic model. Pancreatic F_V values of the 12 AIP patients (81.3/min) were significantly higher than those of 22 PC patients (19.3/min, p=0.0005). Pancreatic V_D values of the AIP patients (28.8) were significantly lower than those of the PC patients (93.6, p=0.0084). Moreover, pancreatic R² values of the AIP patients (0.659) were significantly higher than those of the PC patients (0.250, p<0.0001). Perfusion CT is useful to distinguish AIP from PC by the comparison of the parameters of blood flow, distribution and blood perfusion pattern.

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A male in his 40's was admitted to our hospital due to upper abdominal discomfort for 1 week. Blood chemistry suggested inflammation and slightly elevated levels of pancreatic enzymes. CT revealed a focal tumor in the pancreatic tail and a slight contrast enhancement in the late phase. EUS showed a low echoic tumor 43mm×27mm in size. MRI revealed the tumor to have low intensity in T1WI, high intensity in T2WI, and higher imaging in DWI. ERCP showed main pancreatic ductal narrowing over 20mm in the pancreatic tail. EUS-FNA revealed no malignancy or chronic inflammation. Serum IgG4 was elevated (432mg/dl). The final diagnosis was autoimmune pancreatitis with focal enlargement of the pancreatic tail, and steroid therapy was initiated. After one week, diffusion-weighted MRI revealed that the high-density area in the pancreatic tail was smaller and lower in intensity. The apparent diffusion coefficiency (ADC) was reduced from 1.25×10^-3mm²/s to 1.05×10^-3mm²/s. After 2 weeks, pancreatic tail swelling and main pancreatic duct narrowing were improved.

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A 67-year-old male visited our hospital with a chief compliant of lower left abdominal pain, and extracorporeal ultrasonography (US) revealed the presence of a mass in the pancreatic head. Therefore, he was admitted to this department for intensive examination and treatment. US showed a mass measuring 10×10mm in size with low echo level partially coexisting with a high echo level in the pancreatic head, with no evidence of dilatation of the main pancreatic duct. In the coronal arterial phase of multidetector-row computed tomography (MDCT), a pale low-density area was observed located just beneath the pancreatic capsule, remote from the main pancreatic duct. Endoscopic retrograde cholangiopancreatography (ERCP) showed no obstruction or stenosis of the pancreatic duct. The patient was diagnosed as having stage I pancreatic cancer, and was transferred to the Department of Surgery, where he underwent pancreatoduodenectomy. The postoperative pathological diagnosis was invasive pancreatic ductal carcinoma (well-differentiated to poorly differentiated tubular adenocarcinoma) and because metastasis was found in No. 13a lymph node, the diagnosis was upstaged to stage II. This is a report of a rare case of pancreatic-field-type small pancreatic cancer not involving the main pancreatic duct.

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A 60-year-old woman was diagnosed with autoimmune pancreatitis (AIP) of the tail of the pancreas in 2001. She recovered following steroid therapy; however, approximately 1 year after discontinuing treatment, AIP relapsed at the head of the pancreas, resulting in obstructive jaundice. Steroid therapy was restarted and again tapered after the patient recovered. As a maintenance dose, she continued to take prednisolone (5mg) on alternate days; nevertheless, AIP recurred at the head and the tail of the pancreas and intra-hepatic biliary strictures in 2008. Although steroid therapy is usually maintained for at least 3 years, some patients may need longer maintenance therapy, particularly patients with diffuse pancreas swelling, proximal bile duct involvement, and extra-pancreatic lesions. Our case suggests that AIP requires more careful observation because this condition can recur several times at different sites, even after 6 years of steroid maintenance therapy.

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A 58-year-old man who had undergone right partial nephrectomy for right renal cell carcinoma (RCC) thirteen years ago went to the nearest hospital because of tarry stool. Due to the severe anemia (Hb 5.4mg/dl), an upper GI series was performed and revealed bleeding from the ulcer of a Type II tumor in the second portion of duodenum. Bleeding was clipped and an enhanced-CT showed four hypervascular tumors in the pancreatic head. It was diagnosed as duodenal invasion of metastatic pancreatic tumors from RCC, and pancreaticoduodenectomy was performed. Microscopic examination of the resected pancreas showed clear cell carcinoma compatible with metastasis from RCC. Cases of pancreatic metastases from RCC have been reported. A search of the literature yielded nine cases of hemorrhage caused by pancreatic metastases from RCC. Surgical resection should be firstly selected for gastrointestinal bleeding due to pancreatic metastasis from RCC.

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