Clinicopathology of pancreaticobiliary maljunction: relationship between alterations in background biliary epithelium and neoplastic development

Identification of changes in bile composition in pancreaticobiliary reflux based on liquid chromatography/mass spectrometry metabolomics

INTRODUCTION

Pancreaticobiliary reflux (PBR) can induce gallstone formation; however, its pathogenic mechanism remains unclear. In this study, we explored the mechanism of PBR by the non-targeted metabolomic analysis of bile in patients with PBR.

OBJECTIVE

The aim of this study was to investigate the pathogenic mechanism in PBR by the non-targeted metabolomic analysis of bile collected during surgery.

METHODS

Sixty patients who underwent gallstone surgery at our center from December 2020 to May 2021 were enrolled in the study. According to the level of bile amylase, 30 patients with increased bile amylase ( > 110 U/L) were classified into the PBR group, and the remaining 30 patients were classified into the control group (≤ 110 U/L). The metabolomic analysis of bile was performed.

RESULTS

The orthogonal projections to latent structure-discriminant analysis of liquid chromatography mass spectrometry showed significant differences in bile components between the PBR and control groups, and 40 metabolites were screened by variable importance for the projection value (VIP > 1). The levels of phosphatidylcholine (PC) and PC (20:3(8Z,11Z,14Z)/14:0) decreased significantly, whereas the levels of lysoPC (16:1(9z)/0:0), lysoPC (15:0), lysoPC (16:0), palmitic acid, arachidonic acid, leucine, methionine, L-tyrosine, and phenylalanine increased.

CONCLUSIONS

Significant differences in bile metabolites were observed between the PBR and control groups. Changes in amino acids and lipid metabolites may be related to stone formation and mucosal inflammation.

Occult pancreaticobiliary reflux is a pathogenic factor of some benign biliary diseases and gallbladder cancer

BACKGROUND

Pancreaticobiliary maljunction (PBM) is a well-known high-risk factor for biliary malignant tumors because of constant pancreaticobiliary reflux (PBR). However, the impact of occult pancreaticobiliary reflux (OPR), which is characterized by high bile amylase levels in individuals with anatomically normal pancreaticobiliary junction, on biliary diseases remains unclear. The aim of this study was to assess the correlation between OPR and biliary diseases.

METHODS

We enrolled 94 consecutive patients with normal pancreaticobiliary junction and primary biliary diseases confirmed by magnetic resonance cholangiopancreatography. We prospectively collected patients' bile samples and measured bile amylase levels. We investigated the incidence of OPR and the difference in bile amylase levels among these patients and assessed the correlation between high bile amylase levels (HBAL) and benign or malignant biliary diseases, as well as the OPR risk factors.

RESULTS

The incidence of OPR was 36.6% in patients with benign biliary diseases, 26.7% in those with cholangiocarcinoma and 62.5% in those with gallbladder cancer. The median bile amylase level tended to be higher in patients with gallbladder cancer than in those with benign biliary diseases, but there was no significant difference (165.5 IU/L vs. 23.0 IU/L, P = 0.212). The prevalence of an HBAL with bile amylase levels of 1000-7500 IU/L was similar in patients with gallbladder cancer and benign biliary diseases. However, the incidence of HBAL with bile amylase levels greater than 7500 IU/L was significantly higher in patients with gallbladder cancer than in those with benign biliary diseases (37.5% vs. 4.2%, P = 0.012). Multivariate logistic regression analysis revealed that choledocholithiasis was an independent risk factor for OPR.

CONCLUSIONS

OPR can occur in benign and malignant biliary diseases, and it may be a pathogenic factor for some benign biliary diseases and a high-risk factor for gallbladder cancer. There is a correlation between choledocholithiasis and OPR.

Papillary hyperplasia of the gallbladder diagnosed as gallbladder cancer before surgery: A case report

Introduction and importance

Gallbladder cancer has a poor prognosis. Therefore, an accurate diagnosis is required, for which various tests are performed. However, in some cases, it is difficult to distinguish between benign and malignant diseases before surgery. Papillary hyperplasia of the gallbladder is known for its secondary changes. Papillary hyperplasia of the gallbladder, which is known for its secondary changes, is a benign disease. We encountered papillary hyperplasia of the gallbladder with morphological changes over the course of 1 year. In addition, the tumor was suggested to be malignant during various examinations. We present a case of papillary hyperplasia of the gallbladder showing an increasing tendency and findings indicative of malignancy on imaging.

Presentation of case

A 70-year-old man underwent routine abdominal ultrasonography every year. We observed that the gallbladder wall was thickened. The tumor size was 24 mm. FDG-PET and other examinations indicated malignancy requiring surgery.

Clinical discussion

Accurate diagnosis of gallbladder tumor is difficult only by diagnostic imaging. There are problems with preoperative cytology and histology. FS can be an important test to avoid extended surgery.

Conclusion

We report a rare case of papillary hyperplasia of the gallbladder, which was difficult to diagnose. Even when morphological changes and imaging findings suggest malignancy, similar findings could appear in papillary hyperplasia of the gallbladder owing to chronic inflammation.

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Gallbladder cancer has a poor prognosis.

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It is difficult to distinguish between benign diseases before surgery.

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Papillary hyperplasia of the gallbladder shows secondary changes.

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Papillary hyperplasia of the gallbladder can be confused for a malignancy.

Impact of DNA double-strand breaks on pancreaticobiliary maljunction carcinogenesis

BACKGROUND

Pancreaticobiliary maljunction (PBM) is a condition characterized by chronic inflammation due to refluxed pancreatic juice into the biliary tract that is associated with an elevated risk of biliary tract cancer. DNA double-strand breaks (DSBs) are considered the most serious form of DNA damage. DSBs are provoked by inflammatory cell damage and are recognized as an important oncogenic event in several cancers. This study used γ-H2AX, an established marker of DSB formation, to evaluate the impact of DNA damage on carcinogenesis in PBM.

METHODS

We investigated γ-H2AX expression immunohistochemically in gallbladder epithelium samples obtained from 71 PBM cases and 19 control cases.

RESULTS

Fourteen PBM cases with gallbladder adenocarcinoma were evaluated at non-neoplastic regions. A wide range of nuclear γ-H2AX staining was detected in all PBM and control specimens. γ-H2AX expression was significantly higher in PBM cases versus controls (median γ-H2AX-positive proportion: 14.4 % vs. 4.4 %, p = 0.001). Among the PBM cases, γ-H2AX expression was significantly higher in patients with carcinoma than in those without (median γ-H2AX-positive proportion: 21.4 % vs. 11.0 %, p = 0.031).

CONCLUSIONS

DSBs occurred significantly more abundantly in the PBM gallbladder mucosa, especially in the context of cancer, indicating an involvement in PBM-related carcinogenesis.

Common bile duct pressure in patients with and without cholelithiasis: A case-control study

BACKGROUND

The reflux of pancreatic enzymes into the bile duct and the gallbladder is an abnormal phenomenon that plays a role in lithogenesis and carcinogenesis. Because the pressure of the common bile duct depends on the pressures of the sphincter of Oddi, its dysfunction would be reflected in an increase in the pressure of the common bile duct in patients with cholelithiasis. The objective of this study was to measure the pressures of the common bile duct in patients with and without cholelithiasis and to relate them to the presence of pancreatobiliary reflux.

METHODS

A prospective case-control study was designed. The study universe was constituted by all patients undergoing total gastrectomy for gastric cancer stages I and II over 30 months. The primary outcome measure was to establish differences between common bile duct pressures in patients with and without cholelithiasis.

RESULTS

Common bile duct pressures in patients with gallstones showed a significant elevation (16.9 mmHg) compared to patients without gallstones (3.3 mm Hg) (p < 0.0001). These pressures correlated with the levels of amylase and lipase in gallbladder bile; higher levels were found in patients with gallstones compared to patients without gallstones (P < 0.0001).

CONCLUSIONS

Common bile duct pressure in patients with cholelithiasis was significantly higher compared to patients without cholelithiasis leading to pancreatobiliary reflux.

Association between the confluent form of pancreatic and bile duct and histopathological findings in pancreaticobiliary maljunction: A case series study

Introduction

Pancreaticobiliary maljunction (PBM) is a congenital anomaly wherein the persistent reflux of the pancreatic juice into the biliary tract induces biliary tract cancer. The prediction criteria for gallbladder carcinogenesis have been reported previously through results obtained from examining carcinogenic and non-carcinogenic cases with the parameters that classified each confluent form in PBM. This study aimed to validate these previous study results and provide new recommendations for gallbladder carcinogenesis prevention.

Methods

Twenty-four patients with PBM underwent hepaticojejunostomy. The prediction criteria for gallbladder carcinogenesis consist of three elements. The confluent forms that satisfied none or one of the three criteria were defined as a low score group, and those that satisfied two or three were defined as the high score group. Immunohistology and pathological search were performed on the gallbladders' sections in both groups to evaluate chronic inflammation.

Results

The cases with dysplasia, positive Ki67 labeling index, and gallbladder cancer were more common in the high score group and tended to have more lymphocyte infiltration. These findings indicate that the degree of inflammation and cell proliferation might be more severe in the high score group than in the low score group.

Conclusions

There is a close relationship between the confluent form and the histopathological findings of the gallbladder in patients with PBM. The confluent forms observed in the high score group might have an additional correlation with increased proliferation activity and subsequent malignant transformation of the gallbladder epithelium.

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Pancreaticobiliary maljunction (PBM) may induce biliary tract cancer.

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This is the first report showing a correlation between the form in PBM and pathological findings of the gallbladder.

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We were able to show that PBM has a group with confluent forms with a strong carcinogenic tendency.

Telomere length of gallbladder epithelium is shortened in patients with congenital biliary dilatation: measurement by quantitative fluorescence in situ hybridization

BACKGROUND

Congenital biliary dilatation (CBD) is a congenital malformation involving both dilatation of the extrahepatic bile duct and pancreaticobiliary maljunction. Persistent reflux of pancreatic juice injures the biliary tract mucosa, resulting in chronic inflammation and higher rates of carcinogenesis in the biliary tract, including the gallbladder. Telomeres are repetitive DNA sequences located at the ends of chromosomes. Chromosomal instability due to telomere dysfunction plays an important role in the carcinogenesis of many organs. This study was performed to determine whether excessive shortening of telomeres occurs in the gallbladder mucosa of patients with CBD.

METHODS

Resected gallbladders were obtained from 17 patients with CBD, ten patients with cholecystolithiasis without pancreatic juice reflux, and 17 patients with normal gallbladders (controls) (median age of each group of patients: 37, 50, and 53 years, respectively). The telomere lengths of the gallbladder epithelium were measured by quantitative fluorescence in situ hybridization using tissue sections, and the normalized telomere-to-centromere ratio (NTCR) was calculated.

RESULTS

The NTCRs in the CBD, cholecystolithiasis, and control groups were 1.24 [interquartile range (IQR) 1.125-1.52], 1.96 (IQR 1.56-2.295), and 1.77 (IQR 1.48-2.53), respectively. The NTCR in the CBD group was significantly smaller than that in the cholecystolithiasis and control groups (p = 0.003 and 0.004, respectively), even in young patients.

CONCLUSIONS

Our findings indicate that telomere shortening in the gallbladder mucosa plays an important role in the process of carcinogenesis in patients with CBD. These results support the recommendation of established guidelines for prophylactic surgery in patients with CBD because CBD is a premalignant condition with excessive telomere shortening.

Synchronous primary gallbladder and pancreatic cancer associated with congenital biliary dilatation and pancreaticobiliary maljunction

Introduction

Synchronous double cancer of the gallbladder and pancreas that is associated with congenital biliary dilatation (CBD) and pancreaticobiliary maljunction (PBM) is extremely rare. PBM is frequently reported in Asia, particularly in Japan. We report a surgical case of synchronous double cancer in a patient with primary gallbladder and pancreatic cancer.

Presentation of case

A 72-year-old woman with epigastralgia underwent subtotal stomach-preserving pancreaticoduodenectomy and gallbladder bed resection for synchronous primary gallbladder and pancreatic head cancer. Histopathological examination revealed moderately differentiated ductal adenocarcinoma of the pancreatic head and well-differentiated tubular adenocarcinoma at the bottom of the gallbladder.

Conclusion

Synchronous gallbladder and pancreatic cancer is extremely rare. It is necessary to determine the optimal surgical course taking into consideration the degree of tumor progression. This is the second case of synchronous primary gallbladder and pancreatic cancer associated with CBD accompanied by PBM.

Primary papillary hyperplasia of the gallbladder mimicking gallbladder cancer

Primary papillary hyperplasia of the gallbladder (PPHG) is a rare entity. PPHG is a benign diffuse mucosal projection without any background chronic inflammation-related disease of the gallbladder or bile ducts. Reported cases of PPHG are limited in that its characteristics are not well defined. We herein report a case of PPHG mimicking gallbladder cancer in radiologic investigations and present a review of the literature. Also coincident erythroderma is discussed.

Recurrent gallstones in residual bile ducts after surgery for pancreaticobiliary maljunction: A case report and literature review

Pancreaticobiliary maljunction (PBM) is a type of congenital anomaly present in pancreatic duct development. Surgery is a reliable treatment for acute pancreatitis and biliary calculi induced by PBM, and can reduce the risk of carcinoma from congenital biliary dilatation. However, there have been few reports on postoperative complications. Here we report a case of recurrent gallstones in residual bile ducts after surgery for PBM. A review of the literature was also performed.

Pancreaticobiliary maljunction is associated with common bile duct carcinoma: a meta-analysis

Objective. Pancreaticobiliary maljunction (PBM) has been reported to be associated with an increased risk of gallbladder carcinoma. However, the relationship between PBM and common bile duct carcinoma (CBDC) remains unclear. We aimed to conduct a meta-analysis to determine the available evidence on the association between PBM and CBDC. Methods. The pooled odds ratio (OR) and standard mean differences (SMD) with 95% confidence interval (95% CI) were used to estimate the effects. Results. A total of eight case-control studies and two cohort studies were identified. The incidence of PBM was higher in CBDC patients than in controls (OR = 1.45; 95% CI, 1.19–1.76). Compared with patients without PBM, CBDC patients with PBM were younger at the diagnosis age (SMD = −0.46; 95% CI, −0.64 to −0.28). A difference in the incidence of associated CDC was found between CBDC patients with or without PBM (OR = 2.14; 95% CI, 1.60–2.87). Conclusions. Compared with benign biliary tract diseases, the incidence of PBM was higher in CBDC patients, especially in relatively young patients. We also found that the incidence of CDC was higher in CBDC patients with PBM. These findings showed positive association between PBM and CBDC, which may help in identifying high-risk individuals.

Biliary Proliferative Lesions in the Sprague-Dawley Rat

Whether biliary proliferative lesions in nonclinical species are predictive of potential hepatotoxicity in humans depends, at least in part, on the nature and severity of such changes in the nonclinical species. We reviewed published literature (clinical and nonclinical) and experimental data from rat toxicology studies conducted by GlaxoSmithKline and the National Institute of Environmental Health Sciences’ National Toxicology Program in an effort to better characterize the relative risk of hepatobiliary effects in humans. Available evidence supports the interpretation that minimal “typical” appearing bile duct hyperplasia limited to the portal triads may be considered non-adverse in the rat and is of little to no concern to humans. The toxicological relevance of mild to moderate “typical” hyperplasia is less certain, and may be considered adverse in the rat and potentially pose a risk for humans, particularly if accompanied by evidence of hepatobiliary injury or functional compromise. In addition, any proliferative lesion that includes atypical or dysplastic epithelial changes, oval cell proliferation, and/or significant extension beyond the portal tracts is considered more ominous and may be considered adverse in the rat.

Recent advances and problems in the management of pancreaticobiliary maljunction: feedback from the guidelines committee

Clinical practice guidelines on how to deal with pancreaticobiliary maljunction (PBM) were made in Japan in 2012, representing a world first. Using a narrow definition, congenital biliary dilatation involves only Todani type I (except type Ib) and type IV-A, both of which are accompanied by PBM in almost all cases. Prospective ultrasonographic study revealed that the maximum diameter of the common bile duct increased with age. Pathophysiological conditions due to pancreatobiliary reflux occur in patients with high confluence of the pancreaticobiliary ducts, a common channel ≥ 6 mm long and occlusion of communication during contraction of the sphincter of Oddi. Since PBM can be diagnosed by magnetic resonance cholangiopancreatography, multi-planar reconstruction multi-detector row computed tomography and endoscopic ultrasonography, the current diagnostic criteria should be revised to take these diagnostic imaging modalities into consideration. According to a nationwide survey, biliary cancer occurred in 21.6% of adult patients with PBM with biliary dilatation and 42.2% of patients with PBM without biliary dilatation. In biliary cancer associated with PBM without biliary dilatation, 88.1% were gallbladder cancer. Treatment for PBM with biliary dilatation is prophylactic flow-diversion surgery, but further investigations and surveillance studies are needed to clarify the appropriate surgical strategy for PBM without biliary dilatation.

Current knowledge on pancreaticobiliary reflux in normal pancreaticobiliary junction

Knowledge on pancreaticobiliary reflux in normal pancreaticobiliary junction and their pathologic implications has experienced tremendous progress during the last few years. This article reviews the current knowledge on this condition and its pathological implications on gallbladder diseases. Many publications with different levels of evidence were found supporting biliary carcinogenesis associated with pancreaticobiliary reflux in normal and abnormal pancreaticobiliary junction. Also, there are many publications supporting the common occurrence of pancreaticobiliary reflux in normal pancreaticobiliary junction, and sphincter of Oddi dysfunction as the most plausible cause of this condition. Although an important body of research has been published regarding pancreaticobiliary reflux in normal pancreaticobiliary junction and their clinical significance, the current evidence does not fully support what has been suggested. The reflux of pancreatic enzymes into the bile tract and gallbladder is a fascinating subject of study which is open to active research. The final demonstration of the pathophysiology and consequences of PBR in NPBL and support by evidence level type I would constitute a major breakthrough in the understanding and eventually in the treatment of gallbladder diseases.

Pancreaticobiliary reflux in patients with a normal pancreaticobiliary junction: Pathologic implications

Knowledge on pancreaticobiliary reflux in normal pancreaticobiliary junction and its pathologic implications has experienced tremendous progress during the last few years. This editorial reviews the current knowledge on this condition and its pathological implications on gallbladder diseases. The following aspects were defined appropriate for discussion: (1) Evidence of carcinogenesis associated with pancreaticobiliary reflux; (2) Evidence of pancreaticobiliary reflux in normal pancreaticobiliary junction; and (3) Evidence of sphincter of Oddi (SO) dysfunction as a cause of pancreaticobiliary reflux in normal pancreaticobiliary junction. The articles reviewed were selected and classified according to five levels of evidence: LevelI, meta-analysis double-blind randomized clinical trials, Level II, cohort non-blinded studies and non-randomized clinical trials, Level III, good quality case-control studies and non-randomized cohort studies, Level IV, case series and poor quality case-control studies, and Level V, case report articles and experts’ opinion. Evidence levels II, III, IV and V were found to support biliary carcinogenesis associated with pancreaticobiliary reflux in normal and abnormal pancreaticobiliary junction. The same levels of evidence were found to support the common occurrence of pancreaticobiliary reflux in normal pancreaticobiliary junction, and SO dysfunction as the most plausible cause of this condition. Although an important body of research has been published regarding pancreaticobiliary reflux in normal pancreaticobiliary junction and its clinical significance, the current evidence does not fully support what has been suggested. Studies with evidence level I have not been undertaken. This is a fascinating subject of study, and if finally supported by evidence level I, the importance of this condition will constitute a major breakthrough in biliary pathology.

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.

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.

Papillary hyperplasia of the gallbladder in pancreaticobiliary maljunction represents a senescence-related lesion induced by lysolecithin

Cellular senescence, an irreversible growth arrest, is considered to play as safeguard against malignant progression, though such a mechanism is speculative in human carcinogenesis. In gallbladder carcinoma, cholecystolithiasis and pancreaticobiliary maljunction (PBM) are major risk factors. Here, by using 113 surgically resected gallbladders and cultures of human gallbladder epithelial cells (HGECs) and gallbladder carcinoma cell line (TGBC2TKB), we examined carcinogenesis with respect to cellular senescence. Among 15 cases of PBM in which carcinoma was found in 4 cases, nonneoplastic gallbladder mucosa showed diffuse papillary hyperplasia (PHP). PHP was not found in gallbladders with cholecystolithiasis. Interestingly, PHP exhibited senescent features such as expression of p16(INK4A) and low cell proliferative activity. In contrast, EZH2, a polycomb group protein, was overexpressed in intraepithelial neoplasm and carcinoma in gallbladders with cholecystolithiasis. In PBM, EZH2 was expressed only in carcinoma foci but not in PHP. Cultured HGECs treated with lysolecithin, the level of which is elevated in gallbladder bile of PBM, showed increased expression of p16(INK4A) and senescence-associated beta-galactosidase. Conversely, enforced overexpression of EZH2 in senescent HGECs reduced p16(INK4A) expression. A knockdown of EZH2 in cultured TGBC2TKB cells increased p16(INK4a) expression. In conclusion, PHP in PBM may act as a barrier to malignant transformation for decades. EZH2 may be responsible for the escape from cellular senescence followed by malignant transformation in the gallbladder of PBM.

A case of a choledochal cyst associated with a lymphatic infiltration of a hyperplastic gallbladder epithelium

A 4-year-old girl with a congenital choledochal cyst (Todani IV-A, Komi type A) underwent a resection of the dilated common bile duct and gallbladder. Histologic studies of the gallbladder showed a general hyperplastic change associated with cribriform proliferation at the gland base of the gallbladder. In this region, clusters of cribriform glands were found within the lymphatic vessels, compatible with lymphatic infiltration of tumor cells. However, careful histologic studies did not reveal any apparent neoplastic changes in the gallbladder and common bile duct, so a final diagnosis of epithelial atypism with reactive hypertrophy was made. The displacements observed in the lymphatics are just an incidental finding in a proliferative process of the hyperplastic gallbladder epithelium. In the follow-up observation for 3 years, the patient is doing well without evidence of tumor recurrence. These results suggest that a mere lymphatic infiltration of hyperplastic gallbladder epithelium should not be directly considered as evidence of carcinogenesis.

Biliopancreatic reflux-pathophysiology and clinical implications

The common bile duct and the main pancreatic duct open into the duodenum, where they frequently form a common channel. The sphincter of Oddi is located at the distal end of the pancreatic and bile ducts; it regulates the outflow of bile and pancreatic juice. In patients with a pancreaticobiliary maljunction, the action of the sphincter does not functionally affect the junction. Therefore, in these patients, two-way regurgitation (pancreatobiliary and biliopancreatic reflux) occurs. This results in various pathological conditions of the biliary tract and the pancreas. Biliopancreatic reflux could be confirmed by: operative or postoperative T-tube cholangiography; CT combined with drip infusion cholangiography; histological detection of gallbladder cancer cells in the main pancreatic duct; and reflux of bile on the cut surface of the pancreas. Biliopancreatic reflux occurs frequently in patients with a long common channel. Although the true prevalence, degree, and pathophysiology of biliopancreatic reflux remain unclear, biliopancreatic reflux is related to the occurrence of acute pancreatitis. Obstruction of a long common channel easily causes bile flow into the pancreas. Even if no obstruction is present, biliopancreatic reflux can still result in acute pancreatitis in some cases.

Metachronous double cancer of the gallbladder and pancreas associated with pancreaticobiliary maljunction

A 50-year-old Japanese woman complained of abdominal and back pain. Ten years previously she had undergone cholecystectomy, choledochectomy, and Roux-en-Y choledochojejunostomy for gallbladder cancer associated with pancreaticobiliary maljunction without bile duct dilatation. On the present admission, ultrasonography (US) and computed tomography (CT) demonstrated a large mass, 60 mm in size, in the pancreatic tail. Endoscopic retrograde cholangiopancreatography (ERCP) showed obstruction of the main pancreatic duct in the tail of the pancreas and revealed that the pancreatic duct was joined to the bile duct 25 mm above the papilla of Vater. The patient underwent distal pancreatectomy, splenectomy, left adrenalectomy, and partial gastrectomy. Histological examination revealed moderately differentiated ductal adenocarcinoma that had invaded to the proper muscle of the stomach. Double cancer of the gallbladder and pancreas in a patient with pancreaticobiliary maljunction is rare. Although the etiology of cancer of the pancreas associated with pancreaticobiliary maljunction is unclear, we should pay close attention to the pancreas as well as the biliary tract during the long-term follow-up of patients with pancreaticobiliary maljunction after they have undergone a choledochojejunostomy.

Double cancer of the cystic duct and gallbladder associated with low junction of the cystic duct

We report a case of double cancer of the cystic duct and gallbladder associated with low junction of the cystic duct. A 73-year-old woman was admitted to the hospital complaining of upper abdominal pain. Endoscopic retrograde cholangiography showed a stenotic lesion in the lower common bile duct and no visualization of the cystic duct or gallbladder. Enhanced computed tomography revealed a heterogeneously enhanced tumorous lesion around the lower bile duct in the pancreatic head. A diagnosis of cancer arising from the cystic duct that entered the lower part of the common hepatic duct was made by intraductal ultrasonography, which showed an intraluminal protruding lesion in the cystic duct. Isolated gallbladder cancer was also diagnosed, by abdominal computed tomography. She underwent pancreaticoduodenectomy with dissection of regional lymph nodes. Histological examination revealed moderately differentiated adenocarcinoma of the cystic duct and well-differentiated adenocarcinoma of the gallbladder. Double cancer of the cystic duct and gallbladder is extremely rare, and this case also suggests a relationship between a low junction of the cystic duct and neoplasm in the biliary tract.

Pancreaticobiliary maljunction and carcinogenesis to biliary and pancreatic malignancy

BACKGROUND

It is widely accepted that congenital choledochal cyst is associated with pancreaticobiliary maljunction (PBM). But, PBM is an independent disease entity from choledochal cyst. PBM is synonymous with "abnormal junction of the pancreaticobiliary ductal system", "anomalous arrangement of pancreaticobiliary ducts", "anomalous union of bilio-pancreatic ducts", etc. Cases with PBM not associated with biliary duct dilatation are often found, and these cases are frequently complicated gallbladder cancer. The Japanese Study Group of Pancreaticobiliary Maljunction was started in 1983, and defined diagnostic criteria and nationwide registration system of PBM cases was started. PBM is defined as a union of the pancreatic and biliary ducts which is located outside the duodenal wall. Bile and pancreatic juice reflux and regurgitate mutually.

BILIARY CARCINOGENESIS

The most bothersome problem is biliary carcinogenesis. Gallbladder cancers arise in 14.8% and bile duct cancers arise in 4.9%. The incidence of the gallbladder carcinoma of PBM without bile duct dilatation is 36.1%. Many investigators have tried to clarify the carcinogenic process, from various aspects. The biliary epithelia are injured by harmful substances, and in the course of repair, multiple alterations of oncogenes and tumor suppressor genes are followed, and they lead to carcinoma through multistage interaction. In the biliary epithelia of PBM, incidence and degree of hyperplasia are characteristic. K-ras gene mutations are observed in the cancerous as well as noncancerous lesions of biliary tract of PBM patients. Mutations of p53 gene and overexpression of p53 protein are also found in the cancerous and noncancerous lesions. These changes are called "hyperplasia-carcinoma sequence".

TREATMENT

Total excision of the extrahepatic bile duct with gallbladder followed by hepaticojejunostomy, Roux-en-Y, or end-to-side hepaticoduodenostomy are treatment of choice, even for cases with not dilated bile duct, because the incidence of cancer in the nondilated bile duct is not negligible, and genetic changes are seen in a nondilated bile duct.

Gallbladder carcinoma associated with occult pancreatobiliary reflux in the absence of pancreaticobiliary maljunction

We herein report a case of gallbladder carcinoma associated with occult pancreatobiliary reflux (PR) in the absence of pancreatobiliary maljunction. A 67-year-old woman was referred to our hospital for the evaluation and treatment of a gallbladder tumor. Ultrasonography and computed tomography showed a nodular lesion in the fundus of the gallbladder, indicating the possibility of a gallbladder carcinoma. Endoscopic ultrasonography showed the nodular tumor and thickness of the surrounding epithelium. Endoscopic retrograde cholangiopancreatography revealed a normal pancreaticobiliary junction without the common channel and a slight dilatation of the common bile duct (15 mm in diameter). An open cholecystectomy and partial resection of the liver bed of the gallbladder with regional lymphadenectomy was performed. A C-tube was inserted from the cut end of the cystic duct into the common bile duct to prevent bile stasis. Biliary amylase and lipase levels sampled in the gallbladder were 2604 IU/l and 775 IU/l, respectively. Biliary amylase level in the bile collected from the C-tube in the common bile duct was 119 550 IU/l on postoperative day (POD) 6 and 22 265 IU/l on POD 12. These observations suggested that PR was present in this patient. The histopathological findings of the resected specimen showed a well-differentiated adenocarcinoma of the gallbladder with invasion to the muscle layer and no metastasis of the resected lymph nodes. A high index of nuclear staining for MIB-I in the cancer cells (about 10%) was exhibited, and a few cells in the normal epithelium also stained positive.