Differences between main-duct and branch-duct intraductal papillary mucinous neoplasms of the pancreas

In the last decade,intraductal papillary mucinous neoplasms(IPMNs) have become commonly diagnosed.From a morphological standpoint,they are classified in main-duct IPMNs(MD-IPMNs) and branch-duct IPMNs(BD-IPMNs),depending on the type of involvement of the pancreatic ductal system by the neoplasm.Despite the fact that our understanding of their natural history is still incomplete,recent data indicate that MD-IPMNs and BD-IPMNs show significant differences in terms of biological behaviour with MD-IPMNs at higher risk of malignant degeneration.In the present paper,clinical and epidemiological characteristics,rates of malignancy and the natural history of MD-IPMNs and BD-IPMNs are analyzed.The profile of IPMNs involving both the main pancreatic duct and its side branches(combined-IPMNs) are also discussed.Finally,general recommendations for management based on these differences are given.

Outcomes of nonresected main-duct intraductal papillary mucinous neoplasms of the pancreas

AIM:To compare characteristics and outcomes of resected and nonresected main-duct and mixed intraductal papillary mucinous neoplasms of the pancreas(IPMN).METHODS:Over a 14-year period,50 patients who did not undergo surgery for resectable main-duct or mixed IPMN,for reasons of precluding comorbidities,age and/or refusal,were compared with 74 patients who underwent resection to assess differences in rates of survival,recurrence/occurrence of malignancy,and prognostic factors.All study participants had dilatation of the main pancreatic duct by ≥ 5 mm,with or without dilatation of the branch ducts.Some of the nonsurgical patients showed evidence of mucus upon perendoscopic retrograde cholangiopancreatography or endoscopic ultrasound and/or after fine needle aspiration.For the surgical patients,pathologic analysis of resected specimens confirmed a diagnosis of IPMN with involvement of the main pancreatic duct or of both branch ducts as well as the main pancreatic duct.Clinical and biologic follow-ups were conducted for all patients at least annually,through hospitalization or consultation every six months during the first year of follow-up,together with abdominal imaging analysis(magnetic resonance cholangiopancreatography or computed tomography) and,if necessary,endoscopic ultrasound with or without fine needle aspiration.RESULTS:The overall five-year survival rate of patients who underwent resection was significantly greater than that for the nonsurgical patients(74% vs 58%; P =0.019).The parameters of age(< 70 years) and absence of a nodule were associated with better survival(P < 0.05); however,the parameters of main pancreatic duct diameter > 10 mm,branch ductdiameter > 30 mm,or presence of extra pancreatic cancers did not significantly influence the prognosis.In the nonsurgical patients,pancreatic malignancy occurred in 36% of cases within a mean time of 33 mo(median:29 mo; range:8-141 mo).Comparison of the nonsurgical patients who experienced disease progression with those who did not progress showed no significant differences in age,sex,symptoms,subtype of IPMN,or follow-up period; only the size of the main pancreatic duct was significantly different between these two sub-groups,with the nonsurgical patients who experienced progression showing a greater diameter at the time of diagnosis(> 10 mm).CONCLUSION:Patients unfit for surgery have a 36% greater risk of developing pancreatic malignancy of the main-duct or mixed IPMN within a median of 2.5 years.

Small serotonin-positive pancreatic endocrine tumors caused obstruction of the main pancreatic duct

We report 2 cases of pancreatic endocrine tumors that caused obstruction of the main pancreatic duct(MPD).A 49-year-old asymptomatic man was referred to our institution because dilation of the MPD was revealed by abdominal ultrasonography(US).No tumor was detected by endoscopic ultrasonography,computed tomography(CT),and magnetic resonance imaging(MRI).The diameter of the MPD was > 20 mm at the body,and no dilation was noted at the head.Although malignancy was not confirmed through cytology or imaging,pancreatic cancer was strongly suspected.Pancreaticoduo-denectomy was performed.Pathological and immunohistochemical examination revealed a 5 mm × 3 mm serotonin-positive endocrine tumor.Fibrosis was present around the MPD and seemed to cause stricture.A 32-year-old asymptomatic man had elevated serum amylase,and US demonstrated dilation of the MPD.No tumor was detected by CT and MRI.Pancreatic cancer was suspected due to stricture and dilation of the MPD.Pancreatectomy of middle part of pancreas was performed.Pathological and immunohistochemical examination revealed a serotonin-positive endocrine tumor sized 5 mm × 4 mm.We report 2 cases of serotonin-positive pancreatic endocrine tumors that caused stricture of the MPD in spite of the small size of the tumor.

Solid pseudopapillary neoplasm of the pancreas in a young male with main pancreatic duct dilatation: A case report

BACKGROUND Solid pseudopapillary neoplasms(SPNs)are rare tumors of the pancreas.Typically,they occur in young females,often have characteristic imaging features,such as cystic components and calcification,and have few effects on the pancreatic duct.CASE SUMMARY A 31-year-old man was admitted to our hospital with the chief complaint of epigastric pain.There was only mild tenderness in his upper abdomen,and blood tests showed only a slight increase in alkaline phosphatase.Contrast-enhanced computed tomography showed a 40-mm-diameter,hypovascular mass in the head of the pancreas,and the main pancreatic duct upstream of the mass was severely dilated.Magnetic resonance imaging showed low intensity on T1-weighted images,with high intensity on T2-weighted image in some parts.Pancreatic ductal adenocarcinoma was the primary differential diagnosis.Portal vein infiltration could not be ruled out,so this case was a candidate for neoadjuvant chemotherapy.Subsequently,endoscopic ultrasound-guided fine needle aspiration was performed,and pathological evaluation and immunostaining suggested a diagnosis of SPN.Thus,pancreatoduodenectomy was performed.One year after the operation,the patient is alive with no recurrence.CONCLUSION Main pancreatic duct dilatation is usually a finding of suspected pancreatic cancer.However,pancreatic duct dilatation can occur in SPN depending on the location and growth speed.Therefore,SPN should be considered in the differential diagnosis of tumors with pancreatic duct dilatation,and pathological evaluation by endoscopic ultrasound-guided fine needle aspiration should be actively performed.

Air in the main pancreatic duct:A case of innocent air

Air in the main pancreatic duct has been reported only rarely and might be associated with either a spontaneous or a surgically induced alteration of the anatomy of the biliary tract.We report a case of "innocent" air found incidentally in the main pancreatic duct.To our knowledge,this is only the third such case reported.A 54-year-old woman presented with hemoptysis that had lasted for 3 d.She underwent a chest computed tomography scan,which revealed not only focal bronchiectasis in the left lower lobe,but also air in the main pancreatic duct and dilatation of the common bile duct.She was managed conservatively for the hemoptysis and no further problems developed.She had no specific gastrointestinal symptoms and had no history of surgery or medication.Her laboratory parameters were normal.Magnetic resonance cholangiopancreatography also demonstrated air in the main pancreatic duct and a dilated common bile duct(CBD).Duodenoscopy revealed separate biliary and pancreatic orifices with patulous openings and some air bubbles appearing in the pancreatic orifice.Endoscopic retrograde cholangiopancreatography(ERCP) showed the dilated CBD and pancreatic duct with some air bubbles,but no other abnormal lesions.She was discharged with no further problems.Most patients with air in the main pancreatic duct have had a pancreatobiliary disease,or a history of pancreatobiliary disease,pancreatobiliary surgery or sphincterotomy.If the air is innocent,as in our case,ERCP should be performed to evaluate any altered sphincteric function or anatomy such as patulous openings.

胰管(修复)外科概述与思考

毗邻主胰管的胰腺良性肿瘤及交界性肿瘤,因其手术剜除时易损伤主胰管而通常选择扩大切除范围,并进行消化道的改建,这种扩大性的手术方式造成过多的医源性损伤,破坏了胰腺正常解剖结构和消化道连续性,不利于病人的预后。随着外科微创理念和医疗技术的不断进步,作者在总结大量机器人胰腺手术经验的基础上,提出了以主胰管架桥修复为核心的胰管(修复)外科的概念,并在临床应用中总结提出了相关的一系列思考。胰管(修复)外科概念的提出与发展有望实现胰腺良性及交界性肿瘤的治疗创伤最小化,以期预后最佳化。

Pathological features and diagnosis of intraductal papillary mucinous neoplasm of the pancreas

Intraductal papillary mucinous neoplasm(IPMN) of the pancreas is a noninvasive epithelial neoplasm of mucinproducing cells arising in the main duct(MD) and/or branch ducts(BD) of the pancreas.Involved ducts are dilated and filled with neoplastic papillae and mucus in variable intensity.IPMN lacks ovarian-type stroma,unlike mucinous cystic neoplasm,and is defined as a grossly visible entity(≥ 5 mm),unlike pancreatic intraepithelial neoplasm.With the use of high-resolution imaging techniques,very small IPMNs are increasingly being identified.Most IPMNs are solitary and located in the pancreatic head,although 20%-40% are multifocal.Macroscopic classification in MD type,BD type and mixed or combined type reflects biological differences with important prognostic and preoperative clinical management implications.Based on cytoarchitectural atypia,IPMN is classified into low-grade,intermediategrade and high-grade dysplasia.Based on histological features and mucin(MUC) immunophenotype,IPMNs are classified into gastric,intestinal,pancreatobiliary and oncocytic types.These different phenotypes can be observed together,with the IPMN classified according to the predominant type.Two pathways have been suggested:gastric phenotype corresponds to less aggressive uncommitted cells(MUC1-,MUC2-,MUC5 AC +,MUC6 +) with the capacity to evolve to intestinal phenotype(intestinal pathway)(MUC1-,MUC2 +,MUC5 AC +,MUC6- or weak +) or pancreatobiliary /oncocytic phenotypes(pyloropancreatic pathway)(MUC1 +,MUC 2-,MUC5 AC +,MUC 6 +) becoming more aggressive.Prognosis of IPMN is excellent but critically worsens when invasive carcinoma arises(about 40% of IPMNs),except in some cases of minimal invasion.The clinical challenge is to establish which IPMNs should be removed because of their higher risk of developing invasive cancer.Once resected,they must be extensively sampled or,much better,submitted in its entirety for microscopic study to completely rule out associated invasive carcinoma.

Role of frozen section assessment for intraductal papillary and mucinous tumor of the pancreas

Intraductal papillary mucinous neoplasms(IPMN) of the pancreas include a spectrum of dysplasia ranging from minimal mucinous hyperplasia to invasive carcinoma and are extensive tumors that often spread along the ductal tree.Several studies have demonstrated that preoperative imaging is not accurate enough to adapt the extent of pancreatectomy and have suggested routinely using frozen sectioning(FS) to evaluate the completeness of resection and also to check if ductal dilatation is active or passive,in order to avoid an excessive pancreatic resection.Separate main duct and branch duct analysis is needed due to the difference in the natural history of the disease.FS accuracy averages 95%.Eroded epithelium on the main duct,severe ductal inflammation mimicking dysplasia and reactive epithelial changes secondary to obstruction can lead to inappropriate FS results.FS results change the planned extent of resection in up to 30% of cases.The optimal cut-off leading to extend pancreatectomy is not consensual and our standard option is to extend pancreatec-tomy if FS reveals:(1) at least IPMN adenoma on the main duct;or(2) at least borderline IPMN on branch ducts;or(3) invasive carcinoma.However,the decision to extend resection must be taken after a multidisciplinary discussion since it does not exclusively depend on the FS result but also on age,general condition and expected prognosis after resection.The main limitation of using FS is the existence of discontinuous("skip") lesions which account for approximately 10% of IPMN in surgical series and can lead to reoperation in up to 8% of cases.

Imaging pancreatobiliary ductal system with optical coherence tomography: A review

An accurate, noninvasive and cost-effective method of in situ tissue evaluation during endoscopy would be highly advantageous for the detection of dysplasia or early cancer and for identifying different disease stages. Optical coherence tomography(OCT) is a noninvasive, high-resolution(1-10 μm) emerging optical imaging method with potential for identifying microscopic subsurface features in the pancreatic and biliary ductal system. Tissue microstructure of pancreaticobiliary ductal system has been successfully imaged by inserting an OCT probe through a standard endoscope operative channel. High-resolution OCT images and the technique's endoscopic compatibility have allowed for the microstructural diagnostic of thepancreatobiliary diseases. In this review, we discussed currently available pancreaticobiliary ductal imaging systems to assess the pancreatobiliary tissue microstructure and to evaluate varieties of pancreaticobiliary disorders and diseases. Results show that OCT can improve the quality of images of pancreatobiliary system during endoscopic retrograde cholangiopancheatography procedure, which may be important in distinguishing between the neoplastic and non-neoplastic lesions.

Clinical implications of accessory pancreatic duct

The accessory pancreatic duct (APD) is the main drainage duct of the dorsal pancreatic bud in the embryo,entering the duodenum at the minor duodenal papilla (MIP).With the growth,the duct of the dorsal bud undergoes varying degrees of atrophy at the duodenal end.Patency of the APD in 291 control cases was 43% as determined by dye-injection endoscopic retrograde pancreatography.Patency of the APD in 46 patients with acute pancreatitis was only 17%,which was significantly lower than in control cases (P < 0.01).The terminal shape of the APD was correlated with APD patency.Based on the data about correlation between the terminal shape of the APD and its patency,the estimated APD patency in 167 patients with acute pancreatitis was 21%,which was signif icantly lower than in control cases (P < 0.01).A patent APD may function as a second drainage system for the main pancreatic duct to reduce the pressure in the main pancreatic duct and prevent acute pancreatitis.Pancreatographic f indings of 91 patients with pancreaticobiliary maljunction (PBM) were divided into a normal duct group (80 patients) and a dorsal pancreatic duct (DPD) dominant group (11 patients).While 48 patients (60%) with biliary carcinoma (gallbladder carcinoma,n=42;bile duct carcinoma,n=6) were identified in PBM with a normal pancreatic duct system,only two cases of gallbladder carcinoma (18%) occurred in DPD-dominant patients (P < 0.05).Concentration of amylase in the bile of DPD dominance was signifi cantly lower than that of normal pancreatic duct system (75 403.5 ± 82 015.4 IU/L vs 278 157.0 ± 207 395.0 IU/L,P < 0.05).In PBM with DPD dominance,most pancreatic juice in the upper DPD is drained into the duodenum via the MIP,and reflux of pancreatic juice to the biliary tract might be reduced,resulting in less frequency of associated biliary carcinoma.

Endoscopic pancreatic duct stent placement for inflammatory pancreatic diseases

The role of endoscopic therapy in the management of pancreatic diseases is continuously evolving; at present most pathological conditions of the pancreas are successfully treated by endoscopic retrograde cholangio- pancreatography (ERCP) or endoscopic ultrasound (EUS), or both. Endoscopic placement of stents has played and still plays a major role in the treatment of chronic pancreatitis, pseudocysts, pancreas divisum, main pancreatic duct injuries, pancreatic fi stulae, complications of acute pancreatitis, recurrent idiopathic pancreatitis, and in the prevention of post-ERCP pancreatitis. These stents are currently routinely placed to reduce intraductal hypertension, bypass obstructing stones, restore lumen patency in cases with dominant, symptomatic strictures, seal main pancreatic duct disruption, drain pseudocysts or fluid collections, treat symptomatic major or minor papilla sphincter stenosis, and prevent procedure-induced acute pancreatitis. The present review aims at updating and discussing techniques, indications, and results of endoscopic pancreatic duct stent placement in acute and chronic in? ammatory diseases of the pancreas.

某自锚式悬索桥预应力主缆孔道补救方案

上海某大桥主桥为双塔自锚式悬索桥,主体结构采用(40+70+40)m三跨塔梁组合结构体系,由钢筋混凝土主塔、预应力混凝土箱梁、主缆、吊索组成。主要针对主缆混凝土浇筑对预应力管道破坏的施工问题进行分析,从施工过程记录、预应力孔道变形参数汇总分析、后续解决流程及方案三方面综合分析,全过程记录施工过程中因混凝土浇筑对主缆预应力孔道造成破坏的成因及对策。通过结合实践数据的过程记录及分析来验证类似问题的解决策略,指导类似项目如何工前预防、工后补救,避免对工程造成不可逆的巨大损失。

自身免疫性胰腺炎(附5例报告)

目的：分析自身免疫性胰腺炎（autoimmune pancreatitis，AIP）患者的影像学表现、临床特征、血清学检查及病理学结果。方法：从2004年12月-2008年11月，回顾分析了5例AIP病例，其中3男2女，平均年龄为58．2岁（范围：54～65岁）。诊断标准符合Kim标准及修订的日本标准。结果：5名AIP患者的临床表现包括：黄疸（5／5）、腹痛（2／5）及糖尿病（3／5）。实验室检查：2名患者血沉增快；3名患者IgG水平升高；4名患者CA19．9升高。CT表现：胰腺弥漫肿大（4／5）或胰头肿块（1／5）；MRCP表现：胆总管下段狭窄（5／5）；ERCP表现：主胰管弥漫性狭窄和胆总管局限性狭窄。4名患者因怀疑胰腺癌而进行了开腹探查手术，此4名患者的病理表现为AIP特征性的胰腺淋巴浆细胞浸润及纤维化。2名患者接受了糖皮质激素治疗，胰腺肿大减轻。其中1名患者在激素减量过程中复发，再次给予激素治疗后2次好转。结论：AIP的影像学表现具有一定特征性。综合分析其影像学表现、临床症状、血清学检查及对激素治疗的反应等因素可以对AIP作出早期正确诊断，以避免不必要的开腹手术。

医源性胆胰肠结合部损伤的预防与处理

目的总结医源性胆胰肠结合部损伤的防治经验.方法病例资料的回顾性分析.我院于1994年1月～2004年12月共发生医源性胆胰肠结合部损伤7例,2例发生在十二指肠乳头括约肌切开后的取石过程中,5例发生在开腹胆道手术中扩张胆总管下段狭窄时.针对损伤实施胰十二指肠切除术2例;胆总管横断型胆总管空肠吻合术5例,其中4例同时加做十二指肠憩室化手术.全部病例均在术中于局部放置双套管引流,术后给予施他宁抑制胰腺分泌.结果6例痊愈;1例死亡.结论在取出结石和扩张狭窄过程中控制好操作力度是防止发生医源性胆胰肠结合部损伤的关键.全胆汁改道和十二指肠憩室化是处理胆胰肠结合部损伤的有效措施,强调全胆汁改道手术和十二指肠憩室化手术同时实施.具体术式推荐横断胆总管型胆管空肠吻合术和胃肠吻合加胃窦部可吸收肠线捆扎术.局部损伤严重时可行胰十二指肠切除术.

胰腺主胰管形态学变化与急性胰腺炎相关性的MRCP研究

目的:采用高场强磁共振胆胰管水成像(magnetic resonance cholangiopancreatography,MRCP)及图像后处理技术,探讨胰腺主胰管形态学变化与急性胰腺炎的相关性。方法:按纳入标准和排除标准收集2012年1月至2013年6月行MRI和2D MRCP检查患者共64例,并分为A、B两组,A组分为急性胰腺炎组,共31例,B组为正常对照组,共33例。两组数据均传输至图像后处理工作站,在PACS系统中选取一幅主胰管显示最清楚且最完整的MRCP图像,利用图像后处理软件分别3次测量其胰腺主胰管曲线长度和头尾直线距离,取其平均值为最后值,主胰管屈曲度为最后值的主胰管曲线长度与头尾直线距离之差的绝对值,记录并行统计学分析。结果:A、B两组主胰管曲线长度分别为(23.74±6.62)cm和(17.24±3.35)cm,头尾直线距离分别为(11.46±1.73)cm和(11.04±1.41)cm,主胰管屈曲度分别为(12.28±5.54)cm和(6.20±3.46)cm。胰腺主胰管屈曲度、主胰管曲线长度A、B两组间均有统计学意义(P=0.009、P=0.001);胰腺主胰管头尾直线距离A、B两组间无统计学意义(P=0.240)。结论:胰腺主胰管形态学变化(屈曲度及曲线长度)与急性胰腺炎具有相关性,胰腺主胰管的屈曲度越大,曲线路径越长,其急性胰腺炎的患病率越高。

新型空调静压送风道主风道流速衰减规律研究

分析了新型静压均匀送风道送风机理 ,研究了主风道内流速衰减规律 ,得出了主风道内流速不呈线性衰减变化规律 ,为进一步摸清送风道的送风机理 ,优化送风道的结构 ,提高送风道的送风均匀性提供了实验依据。

谷冷机制冷降温储粮试验

采用回风管和一机四道的风道设计 ,进行了谷冷机制冷低温储粮试验和复冷试验 。

磁共振胆胰管成像显示分支胰管扩张的意义

目的 探讨分支胰管扩张的磁共振胆胰管成像（MRCP）表现及其对胰腺疾病的诊断价值。资料与方法 MRCP使用Signa Excite HD3.0T MR设备,研究对象为MRCP影像显示分支胰管扩张的病人,包括慢性胰腺炎45例与胰腺癌30例,所有病人均进行常规横断面T1WI、T2WI和MRCP。分析分支胰管扩张的形态、部位及程度,比较2组疾病分支胰管扩张的差异。结果 在形态方面,慢性胰腺炎组分支胰管扩张呈小囊状、分支状及两者兼有的病例数分别为19、42和16例;而胰腺癌组分别为6、29和5例。在部位方面,慢性胰腺炎组分支胰管扩张位于主胰管近段、远段及全程的病例数分别为0、10和35例;而胰腺癌组分别为1、12和17例。结论 3.0T MRCP能清晰显示主胰管及扩张的分支胰管。认识分支胰管扩张的特征有助于慢性胰腺炎和胰腺癌的鉴别诊断。

跨越大截面风管铺设架空地板施工技术

开发了一种跨越主风管区域安装架空地板的新型构架系统,即利用在风管或其他设备上方跨越连接的长横梁和标准横梁来支撑、安装板材,板材再通过预制花盘与横梁固定。该构架系统既满足了地板安装要求,又不会影响地板下方的风管及设备安装,同时可根据现场施工情况随时拆卸并调整板材排布方式,有效地解决了高层建筑地板支架与地面超大截面风管冲突的问题。

FBCDZ-10-No36型通风机进气风道气流稳定性分析

根据某矿压入式轴流主通风机在进气风道入口安装片式消声器,在运行1个月后,第1级部分叶片表面出现裂纹的情况,探讨了影响叶轮入口气流不稳定的主要因素,据此对吸声片尾部和进气风道结构进行了改进,并对改进前后风道内的流场进行数值模拟。结果表明:进气风道入口安装消声器后,在吸声片尾迹中卡门涡街阵列、弯曲风道内流动和风道拐弯处分离流动的共同作用下,叶轮入口截面主流速度分布不均匀程度增强、截面气流压力脉动明显加剧,成为引起叶片疲劳破坏的主要原因;结构改进显著提高了风道内以及叶轮入口截面气流的均匀性和稳定性,从而保证了叶片工作的安全性。