Endoscopic retrograde cholangiopancreatography in children with symptomatic pancreaticobiliary maljunction: A retrospective multicenter study

BACKGROUND Endoscopic retrograde cholangiopancreatography(ERCP)has been widely used in pediatric patients with cholangiopancreatic diseases.AIM To evaluate the efficacy,safety,and long-term follow-up results of ERCP in symptomatic pancreaticobiliary maljunction(PBM).METHODS A multicenter,retrospective study was conducted on 75 pediatric patients who were diagnosed with PBM and underwent therapeutic ERCP at three endoscopy centers between January 2008 and March 2019.They were divided into four PBM groups based on the fluoroscopy in ERCP.Their clinical characteristics,specific ERCP procedures,adverse events,and long-term follow-up results were retrospectively reviewed.RESULTS Totally,112 ERCPs were performed on the 75 children with symptomatic PBM.Clinical manifestations included abdominal pain(62/75,82.7%),vomiting(35/75,46.7%),acholic stool(4/75,5.3%),fever(3/75,4.0%),acute pancreatitis(47/75,62.7%),hyperbilirubinemia(13/75,17.3%),and elevated liver enzymes(22/75,29.3%).ERCP interventions included endoscopic sphincterotomy,endoscopic retrograde biliary or pancreatic drainage,stone extraction,etc.Procedure-related complications were observed in 12 patients and included post-ERCP pancreatitis(9/75,12.0%),gastrointestinal bleeding(1/75,1.3%),and infection(2/75,2.7%).During a mean follow-up period of 46 mo(range:2 to 134 mo),ERCP therapy alleviated the biliary obstruction and reduced the incidence of pancreatitis.The overall effective rate of ERCP therapy was 82.4%;seven patients(9.3%)were lost to follow-up,eight(11.8%)re-experienced pancreatitis,and eleven(16.2%)underwent radical surgery,known as prophylactic excision of the extrahepatic bile duct and hepaticojejunostomy.CONCLUSION ERCP is a safe and effective treatment option to relieve biliary or pancreatic obstruction in symptomatic PBM,with the characteristics of minor trauma,fewer complications,and repeatability.

Endoscopic diagnosis of pancreaticobiliary maljunction

Pancreaticobiliary maljunction (PBM) is a congenital anomaly defined as a junction of the pancreatic and bile ducts located outside the duodenal wall, usually forming a markedly long common channel. As the action of the sphincter of Oddi does not functionally affect the junction in PBM patients, continuous pancreatobiliary reflux occurs, resulting in a high incidence of biliary cancer. PBM can be divided into PBM with biliary dilatation (congenital choledochal cyst) and PBM without biliary dilatation (maximal diameter of the bile duct ≤ 10 mm). The treatment of choice for PBM is prophylactic surgery before malignant changes can take place. Endoscopic retrograde cholangiopancreatography (ERC P) is the most effective examination method for close obs ervation of the pattern of the junction site. When the communication between the pancreatic and bile ducts is maintained, despite contraction of the sphi ncter on ERCP, PBM is diagnosed. In these pat ients, levels of pancreatic enzymes in the bile are gene rally elevated, due to continuous pancreatobiliary reflux via a long common channel. Magnetic resonance cholangiopancreatography and 3D-computed tomography can diagnose PBM, based on findings of an anomalous union between the common bile duct and the pancreatic duct, in addition to a long common channel. Endoscopic ultrasonography and intraductal ultra sonography can demonstrate the junction outside the duodenal wall, and are useful for the diagnosis of asso ciated biliary cancer. Gallbladder wall thickness on ultra so nography can be a screening test for PBM.

Importance of early diagnosis of pancreaticobiliary maljunction without biliary dilatation

AIM:To clarify the strategy for early diagnosis of pancreaticobiliary maljunction(PBM) without biliary dilatation and to pathologically examine gallbladder before cancer develops.METHODS:The anatomy of the union of the pancreatic and bile ducts was assessed by using endoscopic retrograde cholangiopancreatography(ERCP).Patients with a long common channel in which communication between the pancreatic and bile ducts was maintained even during sphincter contraction were diagnosed as having PBM.Of these,patients in which the maximal diameter of the bile duct was less than 10 mm were diagnosed with PBM without biliary dilatation.The process of diagnosing 54 patients with PBM without biliary dilatation was retrospectively investigated.Histopathological analysis of resected gallbladder specimens from 8 patients with PBM without biliary dilatation or cancer was conducted.RESULTS:Thirty-six PBM patients without biliary dilatation were diagnosed with gallbladder cancer after showing clinical symptoms such as abdominal or back pain(n = 16) or jaundice(n = 12).Radical surgery for gallbladder cancer was only possible in 11 patients(31%) and only 4 patients(11%) survived for 5 years.Eight patients were suspected as having PBM without biliary dilatation from the finding of gallbladder wall thickening on ultrasound and the diagnosis was confirmed by ERCP and/or magnetic resonance cholangiopancreatography(MRCP).The median age of these 8 patients was younger by a decade than PBM patients with gallbladder cancer.All 8 patients underwent prophylactic cholecystectomy and bile duct cancer has not occurred.Wall thickness and mucosal height of the 8 resected gallbladders were significantly greater than controls,and hyperplastic changes,hypertrophic muscular layer,subserosal fibrosis,and adenomyomatosis were detected in 7(88%),5(63%),7(88%) and 5(63%) patients,respectively.Ki-67 labeling index was high and K-ras mutation was detected in 3 of 6 patients.CONCLUSION:To detect PBM without biliary dilatation before onset of gallbladder cancer,we should perform MRCP for individuals showing increased gallbladder wall thickness on ultrasound.

Carcinogenesis and chemoprevention of biliary tract cancer in pancreaticobiliary maljunction

Pancreaticobiliary maljunction (PBM) is a high risk factor for biliary tract cancer. In PBM, since the pancreatic duct and bile duct converge outside the duodenal wall beyond the influence of the sphincter of Oddi, pancreatic juice and bile are constantly mixed, producing a variety of harmful substances. Because of this, the biliary mucosa is repeatedly damaged and repaired, which causes an acceleration of cell proliferative activity and multiple gene mutations. Histological changes such as hyperplasia, metaplasia, and dysplasia ultimately result in a high incidence of carcinogenesis. In a nationwide survey by the Japanese Study Group on PBM, coexisting biliary tract cancer was detected in 278 of the 1627 registered cases of PBM (17.1%). Of these cases, in those with dilatation of the extrahepatic bile duct, cancer was often detected not only in the gallbladder but also in the bile ducts. More than 90% of cancer cases without dilatation of the extrahepatic bile duct develop in the gallbladder. Standard treatment for PBM is a cholecystectomy and resection of the extrahepatic bile duct. However, cholecystectomy alone is performed at nearly half of institutions in Japan. Conversely, reports of carcinogenesis in the remnant bile duct or pancreas after diversion surgery are steadily increasing. One of the causes for this is believed to be an accumulation of gene mutations which were present before surgery. Anticancer drugs are ineffective in preventing such carcinogenesis following surgery, thus the postoperative administration of chemopreventive agents may be necessary.

Metachronous cancer of gallbladder and pancreas with pancreatobiliary maljunction

Pancreaticobiliary maljunction is a congenital anomaly in which the junction between the pancreatic duct and the common bile duct is located outside the sphincter of Oddi.It is well known that pancreaticobiliary maljunction is frequently associated with carcinoma of the biliary tract.We report a case of metachronous cancer of the gallbladder and pancreas associated with pancreaticobiliary maljunction and cystic dilatation of common bile duct in a 68-year-old Tunisian woman who underwent a cholecystectomy for acute cholecystitis.The pancreatic tumor was an adenosquamous carcinoma.Pancreaticobiliary maljunction allows for pancreatobiliary or biliopancreatic reflux which may induce biliary tract carcinoma.Few cases of multifocal cancer associated with this anomaly have been reported.The association with pancreatic carcinoma remains rare.Close attention should be given to both the biliary tract system and pancreas during the long-term follow-up of patients with pancreaticobiliary maljunction,especially after they have undergone a choledochojejunostomy.

A case of gallbladder carcinoma associated with pancreatobiliary reflux in the absence of a pancreaticobiliary maljunction:A hint for early diagnosis of gallbladder carcinoma

A 62-year-old man with progressive thickening of the gallbladder wall visited our outpatient clinic. The biliary amylase level in the common bile duct was 19900 IU/L and that of the gallbladder was 127000 IU/L, although endoscopic retrograde cholangiopancreatography revealed no pancreaticobiliary maljunction. Histology demonstrated a moderately differentiated adenocarcinoma of the gallbladder. Pancreatobiliary reflux and associated gallbladder carcinoma were confirmed in the present case, in the absence of a pancreaticobiliary maljunction. Earlier detection of the pancreatobiliary reflux and progressive thickening of the gallbladder wall might have led to an earlier resection of the gallbladder and improved this patient＇s poor prognosis.

Magnetic resonance cholangiopancreatography study of pancreaticobiliary maljunction and pancreaticobiliary diseases

AIM: To discuss the imaging anatomy about pancreaticobiliary ductal union, occurrence rate of pancreaticobiliary maljunction (PBM) and associated diseases in a Chinese population by using magnetic resonance cholangiopancreatography (MRCP).

Relationship between pancreaticobiliary maljunction and gallbladder carcinoma: a meta-analysis

BACKGROUND: Reports on the relationship between pancreaticobiliary maljunction (PBM) and gallbladder carcinoma (GBC) are conflicting. The frequency of PBM in GBC patients and the clinical features of GBC patients with PBM vary in different studies. DATA SOURCES: English-language articles describing the association between PBM and GBC were searched in the PubMed and Web of Science databases. Nine case-control studies fulfilled the inclusion criteria and addressed the relevant clinical questions of this analysis. Data were extracted independently by two reviewers using a predefined spreadsheet. RESULTS: The incidence of PBM was higher in GBC patients than in controls (10.60% vs 1.76%, OR: 7.41, 95% CI: 5.03 to 10.87, P<0.00001). The proportion of female patients with PBM was 1.96-fold higher than in GBC patients without PBM (80.5% vs 62.9%, OR: 1.96, 95% CI: 1.09 to 3.52, P=0.12). GBC patients with PBM were 10 years younger than those without PBM (SMD: -9.90, 95% CI: -11.70 to -8.10, P<0.00001). And a difference in the incidence of associated gallstone was found between GBC patients with and without PBM (10.8% vs 54.3% OR: 0.09, 95% CI: 0.05 to 0.17, P<0.00001). Among the GBC patients with PBM, associated congenital dilatation of the common bile duct was present with a higher incidence ranging from 52.2% to 85.7%, and 70.0%-85.7% of them belonged to the P-C type of PBM (the main pancreatic duct enters the common bile duct). No substantial heterogeneity was found and no evidence of publication bias was observed.CONCLUSIONS: PBM is a high-risk factor for developing GBC, especially the P-C type of PBM without congenital dilatation of the common bile duct. To prevent GBC, laparoscopic cholecystectomy is highly recommended for PBM patients without congenital dilatation of the common bile duct, especially relatively young female patients without gallstones.

Rare variant of pancreaticobiliary maljunction associated with pancreas divisum in a child diagnosed and treated by endoscopic retrograde cholangiopancreatography: A case report

BACKGROUND Pancreaticobiliary maljunction(PBM) is an uncommon congenital anomaly of the pancreatic and biliary ductal system, defined as a union of the pancreatic and biliary ducts located outside the duodenal wall. According to the Komi classification of PBM, the common bile duct(CBD) directly fuses with the ventral pancreatic duct in all types. Pancreas divisum(PD) occurs when the ventral and dorsal ducts of the embryonic pancreas fail to fuse during the second month of fetal development. The coexistence of PBM and PD is an infrequent condition.Here, we report an unusual variant of PBM associated with PD in a pediatric patient, in whom an anomalous communication existed between the CBD and dorsal pancreatic duct.CASE SUMMARY A boy aged 4 years and 2 mo was hospitalized for abdominal pain with nausea and jaundice for 5 d. Abdominal ultrasound showed cholecystitis with cholestasis in the gallbladder, dilated middle-upper CBD, and a strong echo in the lower CBD, indicating biliary stones. The diagnosis was extrahepatic biliary obstruction caused by biliary stones, which is an indication for endoscopic retrograde cholangiopancreatography(ERCP). ERCP was performed to remove biliary stones. During the ERCP, we found a rare communication between the CBD and dorsal pancreatic duct. After clearing the CBD with a balloon, an 8.5 Fr 4-cm pigtail plastic pancreatic stent was placed in the biliary duct through the major papilla. Six months later, his biliary stent was removed after he had no symptoms and normal laboratory tests. In the following 4-year period, the child grew up normally with no more attacks of abdominal pain.CONCLUSION We consider that ERCP is effective and safe in pediatric patients with PBM combined with PD, and can be the initial therapy to manage such cases,especially when it is combined with aberrant communication between the CBD and dorsal pancreatic duct.

Synchronous gallbladder and pancreatic cancer associated with pancreaticobiliary maljunction

We report the case of a 46-year-old woman who presented with chronic intermittent abdominal pain without jaundice; abdominal ultrasonography showed thickening of the gallbladder wall and dilatation of the bile duct. Endoscopic retrograde cholangiopancreaticography showed pancreatobiliary maljunction with proximal common bile duct dilatation. Pancreatobiliary maljunction was diagnosed. A computed tomography scan of the abdomen showed suspected gallbladder cancer and distal common bile duct obstruction. A pancreatic head mass was incidentally found intraoperative. Radical cholecystectomy with pancreatoduodenectomy was performed. The pathological report showed gallbladder cancer that was synchronous with pancreatic head cancer. In the pancreatobiliary maljunction with pancreatobiliary reflux condition, double primary cancer of the pancreatobiliary system should be awared.

Spontaneous necrosis of solid gallbladder adenocarcinoma accompanied with pancreaticobiliary maljunction

A 71-year-old Japanese man with acute cholecystitis and an incarcerated gallbladder （GB） stone was admitted. Plain ultrasonography （US） incidentally detected a mass-like lesion in the fundus. Doppler US revealed that this elevated lesion had no blood flow. Computed tomography showed a relatively low-density mass, measuring 5 cm x 4 cm in diameter, with no positive enhancement. Magnetic resonance imaging showed a mass in the fundus with a slightly low intensity on Tl-weighted images and a slightly high intensity on T2-weighted images. We were agonized in making the qualitative diagnosis of mass-like lesions of the fundus, such as a benign tumor, cancer, or debris. We performed laparoscopic cholecystectomy, because the incarcerated GB stone clearly caused acute cholecystitis. Intra-operative cholangiography clearly revealed pancreaticobiliary maljunction. Amylase levels in the common bile duct and gallbladder were quite high. The elevated lesion in the fundus dearly showed severe necrosis. Although this necrotic nodule included non-viable adenocarcinoma cells, viable cancer cell nests were located in the muscularis propria and subcutaneous layer. Histopathological examination confirmed a solid adenocarcinoma. Thus, we diagnosed it as a gallbladder cancer, based on histopathological analysis of the resected specimen. We therefore undertook radical surgery, including wedge resection of the liver, radical dissection of regional lymph nodes, and resection of the extrahepatic bile duct. Histopathological findings revealed no cancer, hyperplasia or dysplasia in the additionally resected specimens. The patient was finally staged as T2, N0, H0, P0, M（-）, stage Ⅱ. We present the first case of spontaneous necrosis of solid gallbladder adenocarcinoma, with a review of previous studies.

Carcinoma of the papilla of Vater following treatment of pancreaticobiliary maljunction

Pancreaticobiliary maljunction(PBM)is frequently associated with biliary cancer due to reflux of pancreatic enzymes into the choledochus,and even after surgery to correct the PBM such patients still have a risk of residual bile duct cancer.Here,we report the case of a 59-year-old female with carcinoma of the papilla of Vater which developed 2.5 years after choledochoduodenostomy for PBM.During the postoperative follow-up period,computed tomography obtained 2 years after the first operation demonstrated a tumor in the distal end of the choledochus,although she did not have jaundice and laboratory tests showed no abnormalities caused by the previous operation.As a result,carcinoma of the papilla of Vater was diagnosed at an early stage,followed by surgical cure.For early detection of periampullary cancer in patients undergoing surgery for PBM,careful long-term follow-up is needed.

Liver, biliary and pancreatic injuries in pancreaticobiliary maljunction model in cats

BACKGROUND： Pancreaticobiliary maljunction is a high risk factor of pancreatitis and biliary tract cancer. How this maljunction affects the liver remains obscure. This study aimed to examine the effects of pancreaticobiliary maljunction on the liver, pancreas and gallbladder in a cat model.METHODS： A model of choledocho-pancreatic side-to-side ductal anastomosis was created in ten cats. Before the procedure,a small piece of tissue from the liver, pancreas and gallbladder was collected as a control. The common channel formation was checked by cholecystography. The livers, pancreases and gallbladders of these cats were harvested for histological examination. The expression of proliferating cell nuclear antigen in the gallbladder was examined with immunohistochemistry. RESULTS： Seven of the 10 cats survived for 6 months after surgery. The color of the liver was darker in the PBM model than the control specimen, with nodules on the surface. Histological examination showed ballooning changes and inflammatory infiltrations and the histopathological score increased significantly（P〈0.05）. Also, mitochondria swelling and lipid droplet in cytoplasm were observed under an electron microscope. The pancreas also appeared darker in the PBM model than the control specimen and dilated pancreatic ducts were found in three cats. Histopathological examination revealed vascular proliferation and inflammatory infiltration with numerous neutrophils. Gallbladder epithelial cells were featured by expanded endoplasmic reticulum, increased intercellular space and cellular nucleus deformation. The positive cells ofproliferating cell nuclear antigen were increased significantly（P〈0.05）. CONCLUSION： The present study demonstrated that pancreaticobiliary maljunction can lead to the injuries of the liver, pancreas and gallbladder.

Application of imaging techniques in pancreaticobiliary maljunction

Imaging techniques are useful tools in the diagnosis and treatment of pancreaticobiliary maljunction(PBM).PBM is a precancerous lesion often relative to the disease of the pancreas and biliary tract,for example,cholecystolithiasis,protein plugs,and pancreatitis.For patients with PBM,early diagnosis and timely treatment are highly important,which is largely dependent on imaging techniques.The continuous development of imaging techniques,including endoscopic retrograde cholangiopancreatography,magnetic resonance cholangiopancreatography,computed tomography,ultrasound,and intraoperative cholangiography,has provided appropriate diagnostic and therapeutic tools for PBM.Imaging techniques,including non-invasive and invasive,have distinct advantages and disadvantages.The purpose of this paper is to review the application of various imaging techniques in the diagnosis and treatment of PBM.

Diagnosis and clinical implications of pancreatobiliary reflux

The sphincter of Oddi is located at the distal end of the pancreatic and bile ducts and regulates the outflow of bile and pancreatic juice. A common channel can be so long that the junction of the pancreatic and bile ducts is located outside of the duodenal wall, as occurs in pancreaticobiliary maljunction （PBM）; in such cases, sphincter action does not functionally affect the junction. As the hydropressure within the pancreatic duct is usually greater than in the bile duct, pancreatic juice frequently refluxes into the biliary duct （pancreatobiliary reflux） in PBM, resulting in carcinogenetic conditions in the biliary tract. Pancreatobiliary reflux can be diagnosed from elevated amylase level in the bile, secretinstimulated dynamic magnetic resonance cholangiop ancreatography, and pancreatography via the minor duodenal papilla. Recently, it has become obvious that pancreatobiliary reflux can occur in individuals without PBM. Pancreatobiliary reflux might be related to biliary carcinogenesis even in some individuals without PBM. Since few systemic studies exist with respect to clinical relevance and implications of the pancreatobiliary reflux in individuals with normal pancreaticobiliary junction, further prospective clinical studies including appropriate management should be performed.

Pancreaticobiliary reflux as a high-risk factor for biliary malignancy:Clinical features and diagnostic advancements

Pancreaticobiliary junction is composed of complex structure with which biliary duct and pancreatic duct assemble and go out into the ampulla of Vater during duodenum wall surrounding the sphincter of Oddi.Although the sphincter of Oddi functionally prevents the reflux of pancreatic juice,pancreaticobiliary reflux(PBR) occurs when function of the sphincter of Oddi halt.The anatomically abnormal junction is termed pancreaticobiliary maljunction(PBM) and is characterized by pancreatic and bile ducts joining outside of the duodenal wall.PBM is an important anatomical finding because many studies have revealed that biliary malignancies are related due to the carcinogenetic effect of the pancreatic back flow on the biliary mucosa.On the other hand,several studies have been published on the reflux of pancreatic juice into the bile duct without morphological PBM,and the correlation of such cases with biliary diseases,especially biliary malignancies,is drawing considerable attention.Although it has long been possible to diagnose PBM by various imaging modalities,PBR without PBM has remained difficult to assess.Therefore,the pathological features of PBR without PBM have not been yet fully elucidated.Lately,a new method of diagnosing PBR without PBM has appeared,and the features of PBR without PBM should soon be better understood.

Gallbladder carcinoma associated with pancreatobiliary reflux

AIM: To detect the patients with and without pan-creaticobiliary maljunction who had pancreatobiliary reflux with extremely high biliary amylase levels.METHODS: Ninety-six patients, who had diffuse thickness (> 3 mm) of the gallbladder wall and were suspected of having a pancreaticobiliary maljunction on ultrasonography, were prospectively subjected to endoscopic retrograde cholangiopancreatography, and bile in the common bile duct was sampled. Among them, patients, who had extremely high biliary amylase levels (>10 000 IU/L), underwent cholecystectomy, and the clinicopathological findings of those patients with and without pancreaticobiliary maljunction were examined.RESULTS: Seventeen patients had biliary amylase levels in the common bile duct above 10 000 IU/L, including 11 with pancreaticobiliary maljunction and 6 without pancreaticobiliary maljunction. The occurrence of gallbladder carcinoma was 45.5% (5/11) in patients with pancreaticobiliary maljunction, and 50% (3/6) in those without pancreaticobiliary maljunction.CONCLUSION: Pancreatobiliary reflux with extremely high biliary amylase levels and associated gallbladder carcinoma could be identified in patients with and without pancreaticobiliary maljunction, and those patients might be detected by ultrasonography and bile sampling.

Pancreatic duct drainage using EUS-guided rendezvous technique for stenotic pancreaticojejunostomy

The patient was a 30-year-old female who had undergone excision of the extrahepatic bile duct and Rouxen-Y hepaticojejunostomy for congenital biliary dilatation at the age of 7.Thereafter,she suffered from recurrent acute pancreatitis due to pancreaticobiliary maljunction and received subtotal stomach-preserving pancreaticoduodenectomy.She developed a pancreatic fistula and an intra-abdominal abscess after the operation.These complications were improved by percutaneous abscess drainage and antibiotic therapy.How ever,upper abdominal discomfort and the elevation of serum pancreatic enzymes persisted due to stenosis from the pancreaticojejunostomy.Because we could not accomplish dilation of the stenosis by endoscopic retrograde cholangiopancreatography,we tried an endoscopic ultrasonography(EUS) guided rendezvous technique for pancreatic duct drainage.After transgastric puncture of the pancreatic duct using an EUS-fine needle aspiration needle,the guidewire was inserted into the pancreatic duct and finally reached to the jejunum through the stenotic anastomosis.We changed the echoendoscope to an oblique-viewing endoscope,then grasped the guidewire and withdrew it through the scope.The stenosis of the pancreaticojejunostomy was dilated up to 4 mm,and a pancreatic stent was put in place.Though the pancreatic stent was removed after three months,the patient remained symptomfree.Pancreatic duct drainage using an EUS-guided rendezvous technique was useful for the treatment of a stenotic pancreaticojejunostomy after pancreaticoduodenectomy.

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.

Synchronous double cancers of the common bile duct

We report an extremely rare case of synchronous double cancers of the common bile duct without pancreaticobiliary maljunction.Only two similar cases have been reported in the English literature.Endoscopic retrograde cholangiopancreatography showed a tuberous filling defect in the middle and superior parts of the common bile duct,and mild stenosis in the inferior duct.Computed tomography(CT) showed a well enhanced mass in the middle and superior parts of the common bile duct.A single cancer of the middle and superior bile duct was suspected and extra-hepatic bile duct resection was performed.CT eleven months after surgery revealed enhanced inferior bile duct wall and a slightly enhanced tumor within it.Retrospective review of the CT images taken before first surgery showed enhanced inferior bile duct wall without intrabiliary tumor only on the delayed phase.The inferior bile duct tumor was suspected to have originally co-existed with the middle and superior bile duct tumor.Pancreaticoduodenectomy was performed subsequently.Histopathological examination revealed that the middle and superior bile duct tumor was a moderately differentiated tubular adenocarcinoma while the inferior bile duct tumor was a papillary adenocarcinoma.The two tumors were separated and had different histological findings and growth patterns,further suggesting that they were two primary cancers.