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Curative resection is the only treatment for biliary tract cancer that achieves long-term survival. However, patients with advanced biliary tract cancer have only a limited prognosis even after radical surgical resection. Thus, to improve the longterm results, the early detection of biliary tract cancer and subsequent cure seem to be essential. The purpose of this study was to review the literature concerning the risk factors for cancerous and precancerous lesions of the biliary tract, and prophylactic surgery for these factors. It has been reported that pancreaticobiliary maljunction (PBM) with bile duct dilatation is a risk factor for gallbladder cancer and bile duct cancer, while PBM without bile duct dilatation is a risk factor for gallbladder cancer. Thus, in the former group, a prophylactic excision of the common bile duct and gallbladder should be recommended, while in the later group, a prophylactic cholecystectomy without bile duct resection may be the appropriate surgical procedure. It has also been reported that primary sclerosing cholangitis (PSC) is a risk factor for cholangiocarcinoma. Patients with PSC often develop advanced cholangiocarcinoma with a poor prognosis. In patients with PSC, therefore, strict follow-up should be recommended. Adenoma and dysplasia have been regarded as precancerous lesions of gallbladder cancer. A polypoid lesion of the gallbladder that is sessile, has a diameter greater than 10 mm, and /or grows rapidly, is highly likely to be cancerous and should be resected. Although gallstones seem to be closely associated with gallbladder cancer, there is no evidence of a direct causal relationship between gallstones and gallbladder cancer. Thus, a cholecystectomy is not advised for asymptomatic cholecystolithiasis. Controversy remains as to whether adenomyomatosis of the gallbladder and porcelain gallbladder are associated with gallbladder cancer. With respect to ampullary carcinoma, adenoma of the ampulla is considered to be a precancerous lesion. This article discusses the risk factors for cancerous and precancerous lesions of the biliary tract and prophylactic treatment for these factors.

The original publication is available at springerlink.com author, 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 retrograde ultrasonography showed the tumor in the fundus of the gallbladder and thickness of the surrounding epithelium. Endoscopic retrograde cholangiopancreatography revealed a normal pancreaticobiliary junction without the common channel and a mild dilatation of the common bile duct (15 mm in the diameter). An open cholecystectomy and partial resection of the liver bed of the gallbladder with regional lymphadenectomy were performed. A C-tube was inserted from the cut end of the cystic duct into the common bile duct to prevent the bile stasis. Biliary amylase and lipase levels sampled in the gallbladder were 2,604 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/ 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 the nuclear staining for MIB-I in the cancer cells (about 10%) was exhibited, and a few cells of the normal epithelium also stained positive.

Between 1988 and 2003, 38 patients underwent biliary resection for pancreaticobiliary maljunction (PBM). We reviewed the histopathologic findings for the surgically resected specimens to compare the clinical and pathologic features and assess the relationship between changes in the background biliary epithelium and the development of neoplasms.Papillary hyperplasia (PHP) seen in the biliary epithelium of patients with PBM, was classified into grades 0--III in the gallbladder and grades 0--II in the extrahepatic bile duct, according to the extent, and was assessed for links with tumors in the same specimens.The incidence of gallbladder carcinoma was 13/21 in grades I--II, versus 0/16 in grade III, while the incidence of bile duct carcinoma was 4/20 in grade I versus 0/5 in grade II. Furthermore, these incidences for patients below age 50 years and age 50 or older were 1/18 versus 12/20, and 0/14 versus 6/17, respectively.PHP of the biliary epithelium in PBM patients is an important precursor lesion, especially for gallbladder cancer, and the risk becomes greater with age, regardless of the type of pancreatobiliary junction (PBJ) and its location in the biliary tract.

Background/Purpose: We investigated the molecular mechanisms of carcinogenesis in the biliary epithelium in patients with pancreaticobiliary maljunction. Methods: Point mutations of the K-ras gene and the p53 gene, and the overexpression of p53 gene products were examined in the cancerous and noncancerous biliary epithelium of 37 patients with pancreaticobiliary maljunction, with or without biliary dilatation. Results: In the gallbladder epithelium of 5 patients with pancreaticobiliary maljunction associated with biliary carcinoma, K-ras gene mutations were detected in 3 (60%), p53 gene mutations in 3 (60%), and the overexpression of p53 gene products in 4 (80%), while in the bile duct epithelium of these patients, these features were found in 2 of 3 (66.7%), in all of 3 (100%), and none of 3 (0%) specimens, respectively. In the gallbladder epithelium of patients with pancreaticobiliary maljunction without biliary carcinoma, K-ras gene mutations were detected in 8 of 24 (33.3%) specimens, p53 gene mutations were detected in 16 of 27 specimens (59.3%), and the overexpression of p53 protein was detected in 5 of 27 (18.5%) specimens, while in the bile duct epithelium of these patients, these features were found in 10 of 25 (40%) specimens, 14 of 25 (56%) specimens, and 6 of 24 (25%) specimens, respectively. Conclusions: These results suggest that noncancerous lesions of the biliary epithelium in patients with pancreaticobiliary maljunction have mutations of the K-ras gene and/or the p53 gene, which provides genetic evidence that biliary epithelium has high carcinogenic potential.

While gallbladder carcinoma is occasionally associated with pancreaticobiliary maljunction, spontaneous necrosis of carcinoma is extremely rare. We herein present a case of spontaneous necrosis of gallbladder carcinoma associated with direct invasion of viable cancer cell nests to the muscularis propria and subserosal layer located beneath the primary nodules. A 65-year-old Japanese man was admitted to a local hospital, complaining of repeated discomfort in the right hypochondrium. Ultrasonography and computed tomography scanning revealed cholecystitis associated with gallstones. Cholecystectomy was performed, and operative cholangiography demonstrated pancreaticobiliary maljunction. The resected gallbladder showed multiple mixed stones filled with necrotic debris and bile sludge. Scrutiny of the mucosal surface revealed multiple small necrotic nodules in the fundus, which were histologically confirmed to be necrotic remnants of a cancerous glandular structure. Small nests of papillary adenocarcinoma were found beneath the nodules in the muscularis propria and in the venous structure located in the connective tissues next to the divided margin of the gallbladder bed. Resection of S4a and S5 of the liver and resection of the extrahepatic bile duct was then performed to remove the remaining cancerous tissues and/or micrometastasis in the liver and bile duct. The biliary tree was reconstructed with a hepaticoduodenostomy. No cancer nests or any precancerous lesions were found in the additionally resected specimens. This case indicates a unique morphological feature of gallbladder carcinoma associated with pancreaticobiliary maljunction, which provides some insight into the pathogenesis of spontaneous necrosis of gallbladder carcinoma.

We report a case of hyperplastic polyp of the gallbladder in a 6-year-old girl, successfully treated by laparoscopic cholecyctectomy after a 2-year follow-up from the original diagnosis. On her first admission, serum amylase level was very high, so that congenital pancreaticobiliary maljunction (PBM) was suspected. Although it became clear afterwards that the high serum amylase level was derived from a mumps infection, the diagnosis of PBM was not excluded until intraoperative cholangiography was conducted. The tumor in the gallbladder had doubled in size in 2 years. It was not possible to obtain biopsy specimens for histological diagnosis, so the risk of the tumor being malignant could not be completely excluded until surgical resection had been carried out. In spite of the rapid tumor growth, no neoplastic features were seen in the tumor by histopathological examination of the resected specimen; thus, a diagnosis of a hyperplastic polyp of the gallbladder was made.

It is well known that the incidence of biliary cancer is higher in patients with pancreaticobiliary maljunction (PBM) than in individuals without PBM. However, the relationship between PBM and the carcinogenesis remains unclear. The purpose of the present study was to examine histopathologic changes in the mucosa of the gallbladder and bile duct in patients with PBM, and to investigate K-ras oncogene mutation and overexpression of p53 protein in the mucosa. We examined 47 surgical specimens of gallbladder and 36 surgical specimens of bile duct obtained from 48 patients with PBM. The 48 patients were divided into three age groups: group A (0-3 years), group B (4-39 years), and group C (40 years or more). Investigation of K-ras mutation and overexpression of p53 protein was performed using an enriched polymerase chain reaction (PCR) and enzyme-linked mini-sequence assay (ELMA), and by the streptavidin-biotin (SAB) method, using DO-7 antibodies, respectively. Hyperplastic changes in the gallbladder mucosa were observed in patients in the three groups. However, metaplastic or dysplastic changes were observed in the mucosa of only groups B and C. K-ras gene mutation in the gallbladder mucosa was found in 18.8% of the hyperplastic mucosae in group B and in 20% in group C. The mutation was found in 33.3% of lesions with metaplastic change associated with hyperplastic changes and in 25% of lesions with dysplastic changes in group C. No mutation was observed in the non-cancerous mucosae of gallbladders and bile ducts without congenital dilatation of the bile duct. Overexpression of p53 protein was observed only in carcinoma of the gallbladder; in seven of nine advanced carcinomas and in two of three carcinomas in situ. We concluded that the mucosal epithelia of the biliary system in patients with PBM showed a high frequency of gene mutations and the carcinogenesis appeared in involve a multistage process of mutation in the K-ras gene and the p53 suppressor gene.

The coexistence of bile duct carcinoma in choledochal cysts is well known. With large number of cases of congenital bile duct dilatation and pancreaticobiliary maljunction (PBM), it is now apparent that gallbladder carcinoma is more frequent in PBM without bile duct dilatation. The incidence of Gallbladder cancer in choledochal cyst and bile duct cancer in PBM, regardless of the presence of bile duct dilatation is significantly higher than that in control patients with biliary cancer but without PBM. A recent survey shows that the incidence of bile duct cancer in PBM without dilatation is equivalent to that of gallbladder cancer and bile duct cancer in patients with choledochal dilatation. Pathology in PBM is a result of reflux of pancreatic juice and stasis of the mixture in the biliary system. Carcinogenic factors thus present in the biliary contents induce epithelial changes in the biliary tract. In the biliary contents, activated pancreatic enzymes and secondary or deconjugated bile acids are markedly increased and they irritate the biliary mucosa. Mutagens are proven to form in the bile of PBM. In the epithelia of PBM, hyperplasia, metaplasia, and dysplasia are often found, and proliferative activity is increased; furthermore, K-ras gene mutation and overexpression of p53 protein are demonstrated. As for treatment of PBM, whether it is symptomatic or not, an operative procedure, is necessary, to prevent carcinogenic changes in the gallbladder and bile duct. Regardless of whether dilatation is present or not, total excision of the extrahepatic bile duct, along with gallbladder, is the treatment of choice, followed by hepaticojejunostomy or hepaticoduodenostomy.

The results of surgical treatment of pancreaticobiliary maljunction at our department are described. The 67 patients who underwent surgery for this disease were divided by age into an adult group (45 patients, aged 16 years and over) and a pediatric group (22 patients, aged less than 16 years). The incidence of concomitant carcinoma before surgery and the incidence and severity of postoperative cholangitis were compared between these two groups. In addition, the cell proliferating activity of the biliary tract epithelium in cancer-free patients was compared between the two groups, using the proliferating cell nuclear antigen labeling index (PCNA LI). Ten patients (all adults) were diagnosed with cancer (gallbladder carcinoma in 7 and bile duct carcinoma in 3) before surgery. The surgical techniques used for reconstruction in the cancer-free patients were: in the adult group, hepaticoduodenostomy in 9 patients, Roux-en-Y hepaticojejunostomy in 17, jejunal interposition in 8, and another technique in 1. In the pediatric group, hepatico-duodenostomy was performed in 17 patients. Roux-en-Y hepaticojejunostomy in 3, and jejunal interposition in 2. Postoperative cholangitis occurred in 6 adults (including 2 with severe form) and 1 child (mild case). The PCNA LI of the biliary tract epithelium was high compared to control findings in the biliary tract epithelium of 10 adult patients without pancreaticobiliary maljunction. In the adult group with dilated extrahepatic bile ducts (n=10 examined) this index was 11.4% for the bile duct epithelium (control, 1.5%) and 12.7% for the gallbladder epithelium (control, 1.4%). In the adult group with non-dilated extrahepatic bile ducts (n=5 examined) it was 5.9% for the bile duct epithelium and 13.1% for the gallbladder epithelium. In the pediatric group (n=10 with extrahepatic bile duct dilatation) it was 7.5% for the bile duct and 9.7% for the gallbladder epithelium. (Differences from control values were all significant.) These results suggest that surgery for this disease should be performed as early as possible and that extrahepatic bile duct excision and biliary reconstruction should be performed whether or not extrahepatic bile ducts are dilated.

A 5-year-old girl with choledochal cyst (Alonso Lej, type I) and spontaneous perforation of the right hepatic duct during an attack of acute pancreatitis was treated by two-stage surgery. Biliary panperitonitis was diagnosed by abdominal paracentesis, bilirubin and amylase levels in the collected fluid being 41.3 mg/dl and 1812 Somogyi U, respectively. The initial surgery involved simple peritoneal drainage and decompression of the bile duct, followed by removal of a choledochal cyst and the common hepatic bile duct, including the biliary stricture of the left hepatic duct, and biliary reconstruction 5 months later. Cholangiogram after the initial surgery demonstrated pancreaticobiliary maljunction and stricture in the left hepatic duct and the common hepatic duct. Regurgitation of pancreatic juice into the bile duct was shown by the extremely high amylase level (90100 Somogyi U) in the bile drained through a T-tube. The patient is currently well, with normal liver and pancreatic function tests. The experience in this patient is significant in that it should be known that spontaneous perforation of the bile duct may occur at the right hepatic duct in choledochal cyst, causing biliary peritonitis.

End-to-side choledochoduodenostomy was originally used for reconstruction between the duodenum and the biliary tree in iatrogenic bile duct stricture. However, we believe the procedure could be applied for various biliary disorders. We have recently shown the high carcinogenicity of biliary epithelium in patients with pancreaticobiliary maljunction, and consequently we recommend excision of the bile duct, along with appropriate reconstruction of the biliary system to divert the flow of pancreatic juice from bile fluid, to prevent carcinoma in biliary epithelium even in patients without dilatation of the bile duct. The conditions causing primary or recurrent bile duct stones must be removed. We employed this procedure for biliary reconstruction in 42 patients with pancreatico-biliary maljunction and in 30 patients with various benign biliary diseases, such as bile duct stones and benign biliary stenosis. We also used the procedure for palliation in 6 patients with malignant tumors around the head of the pancreas. Among these 78 patients over 20 years, we experienced 5 cases of reflux cholangitis with anastomotic stenosis, for which conservative dilatation was required. This procedure of end-to-side choledochoduodenostomy could be widely applicable for biliary reconstruction in terms of its being simplicity, minimal invasiveness and the establishment of a single physiological route for bile flow into the duodenum.

A unique anomaly of the direct union between the cystic duct and the main pancreatic duct is presented. A 19-year-old man with a history of repeated epigastralgia underwent endoscopic retrograde cholangiopancreaticography that showed a direct union between the cystic duct and the main pancreatic duct. No pancreaticobiliary maljunction was noticed. Cholecystectomy accompanied by resection of the long cystic duct was performed. The excised gallbladder showed cholesterolosis, chronic cholecystitis, and hyperplasia of the pseudopyloric glands microscopically. The patient has been well for 3 years since surgery.

We report a case of 11-year survival with carcinoma arising from a congenital choledochal cyst. A 34-year-old Japanese woman was admitted due to epigastric discomfort. Ultrasonography revealed a choledochal cyst involving a polypoid tumor. Endoscopic retrograde cholangiopancreatography revealed pancreaticobiliary maljunction in which the main pancreatic duct joined the dilated common bile duct 2 cm above the papilla of Vater. A choledochal cyst containing a polypoid tumor was resected with the regional lymph nodes. Grossly, a 2×2-cm papillary tumor was noted in the posterior wall of the choledochal cyst. Microscopically, the tumor was well-differentiated tubular adenocarcinoma invading the mucosa and fibromuscular layer. Neither anticancer chemotherapy nor radiotherapy was performed. The patient recovered uneventfully after the operation and has been well for 11 years without evidence of recurrent cancer. The good results in this patient may have been due to the early stage of the cancer.

The bromodeoxyuridine labelling index (BrdU-LI), ornithine decarboxylase (ODC) activity, and bile elements in the gallbladder were examined in 23 patients to investigate cell kinetics and oncogenesis in gallbladder epithelium with pancreaticobiliary maljunction (PBMJ). The patients were classified into five groups: group I (4 patients without biliary disorder), group II (8 patients with cholecystolithiasis), group III (4 patients with PBMJ), group IV (3 patients with gallbladder cancer and PBMJ), and group V (4 patients with gallbladder cancer). In non-cancerous epithelium, the BrdU-LI in groups III (2.88±3.07%), IV (4.92±2.73), and V (5.93±2.08) was significantly higher than in group I (0.06±0.12), and the ODC activity in groups III (7.83±6.82 pmole CO2/h per mg protein), IV (17.21±9.44), and V (11.27±12.33) was also significantly higher than that in group I (1.39±1.78). Both BrdU-LI and ODC activity were high in epithelium showing metaplasia in 3 patients from groups III and IV. In groups I and II, the lithocholic acid (LCA) fraction showed a positive correlation with BrdU-LI (correlation coefficient, 0.90) and ODC activity (correlation coefficient, 0.91). From these results, it can be concluded that the gallbladder epithelium in patients with PBMJ, and its metaplastic changes, show an increase in cell proliferation, which is important in the progression of cancer.

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.

Pancreaticobiliary maljunction (PBM) is associated with the occurrence of biliary cancer due to pancreatobiliary reflux. We present a case of simultaneous double cancer of the gallbladder and bile duct. A 77-year-old woman who had jaundice, intra- and extra-hepatic biliary ductal dilatation and a space-occupying lesion in the gallbladder and lower bile duct underwent pancreatoduodenectomy. The gallbladder cancer showed papillary carcinoma without mutation of the K-ras gene and with p53 non-sense mutation of CCA (Pro) to CA (Stop) on codon 301 in exon 8. The bile duct cancer revealed a well-differentiated adenocarcinoma without mutation of the K-ras gene and with p53 miss-sense mutation of GTG (Val) to GAG (Glu) on codon 272 in exon 8. There were no mutations of either the K-ras or p53 gene in non-cancerous epithelia. In contrast, only the mucosa of the common channel had p53 protein accumulation and high cell proliferation activity. Therefore, the genetic pathway might be the same in both the gallbladder and bile duct cancer, and a high potential for carcinogenesis might be present in the epithelium of the common channel in patients with PBM.

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.

We report a rare case of metachronous double cancer of the biliary tract. At age 59 years, a man had undergone a cholecystectomy and resection of the liver bed for gallbladder cancer pathologically diagnosed as papillary adenocarcinoma, in 1997. Four years later, he was admitted to our hospital with jaundice. At first, we suspected lymph node metastasis of the gallbladder cancer along the common bile duct. But abdominal computed tomography demonstrated circular wall thickness of the common bile duct, so primary bile duct cancer was strongly suspected. Thus, extended right hepatectomy and pancreaticoduodenectomy were performed after right portal vein embolization. The pathological diagnosis of the resected specimen was well-differentiated tubular adenocarcinoma, and this case was clarified to be metachronous double cancer. A review of the literature regarding double cancer of the biliary tract is presented following this case report. We showed that half of 30 cases of double cancer of the biliary tract were not associated with pancreaticobiliary maljunction, including all 6 metachronous cases.

The congenital anomaly pancreaticobiliary maljunction (PBM) is considered to be a precancerous disease. PBM carcinogenesis is believed to be an accumulation of gene abnormalities, but the early events causing PBM carcinogenesis are still unclear. In the present study, telomerase activity and Bcl-2 expression in the gallbladder mucosa of PBM and non-PBM gallbladders were investigated.The operative gallbladder materials were from five control cases, two cases of non-PBM gallbladder cancer, three of PBM gallbladder cancer, and three of non-neoplastic PBMs. Multiple sampling was performed from each gallbladder. The studies performed were: (1) immunohistochemistry of p53, Ki-67, and Bcl-2; (2) survey of k-ras point mutations; and (3) measurement of telomerase activity in each sample.In the cases of non-PBM cancer, abnormalities from the above studies were detected only in the cancerous lesions. Normal-appearing mucosa did not show Bcl-2 expression or telomerase activity. However, in the cases of PBM cancer, normal-appearing mucosa showed telomerase activity and Bcl-2 expression, but did not show p53, Ki-67, or k-ras abnormalities. In the non-neoplastic PBM, all samples showed Bcl-2 expression, and many showed telomerase activity.Bcl-2 expression and activation of telomerase are probably early events causing carcinogenesis of the PBM gallbladder mucosa. They might be important factors causing carcinogenesis associated with chronic inflammation.

The introduction of the concept of pancreaticobiliary maljunction (PBM) has led to significant progress in the pathogenetic study and surgical treatment of congenital dilatation of the bile duct (CDBD). Clinical studies of 155 patients with CDBD, and basic experimental studies of the mechanisms of bile duct dilatation and associated pancreatitis were conducted. The CDBD was morphologically classified as either cystic or cylindrical type. Clinical signs, symptoms, and laboratory findings were highly dependent on two factors: the age at onset and the reflux of pancreatic juice into the bile duct through the PBM. The canine experimental model of PBM exhibited not only significant bile duct dilatation but also morphological findings similar to those in the CDBD patients. Subsequent studies in a rat model clarified the involvement of activated pancreatic enzyme phospholipase A(2) in PBM-associated pancreatitis. For surgical treatment, cystoenterostomy has been superseded by hepatico-enterostomy after removal of the damaged bile ducts and blocking their communication with the pancreatic duct. Long-term follow-up studies have shown excellent results by confirming the surgical correction based on the pathological principles. Regarding biliary reconstruction, jejunal interposition hepatico-duodenostomy, which is, theoretically, a logical approach was unexpectedly shown to often lead to bile reflux gastritis, so it is now superseded by Roux-en-Y hepaticojejunostomy.

The purpose of this review is to evaluate our current knowledge of the embryologic etiology of pancreaticobiliary maljunction (PBM), its diagnosis, clinical aspects, and treatment, and to clarify the mechanisms of PBM involvement in carcinogenesis. Although the embryologic etiology of PBM still awaits clarification, an arrest of the migration of the common duct of the biliary and pancreatic ducts inwards in the duodenal wall has hitherto been speculated to result in a long common channel in PBM. However, we propose the hypothesis that the etiology of PBM is caused by a disturbance in the embryonic connections (misarrangement) of the choledochopancreatic duct system in the extremely early embryo. That is, PBM is an anomaly caused by a misarrangement whereby the terminal bile duct joins with a branch of the ventral pancreatic duct system, including the main pancreatic duct. PBM is frequently associated with congenital bile duct cyst (CCBD). However, these two anomalies are thought to have different embryonic etiologies. The diagnostic criteria for PBM are the radiological and anatomical detection of the extramural location of the junction of the pancreatic and biliary ducts in the duodenal wall. However, in PBM patients with a short common duct (less than 1 cm in length), detection of the extramural location is difficult. The clinical features of PBM are intermittent abdominal pain, with or without elevation of pancreatic enzyme levels; and obstructive jaundice, with or without acute pancreatitis, while the clinical features of PBM patients with CCBD are primary bile duct stone and acute cholangitis. The optimum approach for the treatment of PBM is the prevention of the reciprocal reflux of bile and pancreatic juice in the pancreas and the bile duct system. To achieve these aims, the surgical approach is most effective, and complete biliary diversion procedures with bile duct resection (for example, choledochoduodenostomy or choledochojejunostomy of the Roux-en-Y type) are most useful. Recently, it has been recognized that the development of biliary ductal carcinoma is associated with PBM. That is, the development of gallbladder cancer occurs frequently in PBM patients without CCBD, and bile duct cancer originating from the cyst wall also occurs in PBM patients with CCBD. It is speculated that the pathogenesis of the bile duct or gallbladder cancer in PBM patients involves the reciprocal reflux of bile and pancreatic juice. Investigations of epithelial cell proliferation in the gallbladder of PBM patients, and of K- ras mutations and p53 suppressor gene mutations, loss of heterozygosity of p53, and overexpression of the p53 gene product in gallbladder cancer and noncancerous lesions in PBM patients have been carried out in various laboratories around the world. The results support the conclusion that PBM is a high risk factor for the development of bile duct carcinoma.

Pancreaticobiliary maljunction (PBM) is a congenital anomaly defined as a union of the pancreatic and biliary duct that is located outside the duodenal wall. The Japanese Study Group on Pancreaticobiliary Maljunction and the Committee for Registration enrolled and analyzed 1627 patients with PBM who had been diagnosed and treated from January 1, 1990 to December 31, 1999 at 141 hospitals throughout the country. There were 1239 patients with dilatation of the bile duct (group A) and 388 patients without dilatation (group B). The average age was 24 years in group A and 47 years in group B; the age was significantly higher in group B. The type of confluence between the terminal choledochus and the pancreatic duct has been classified into three types (type a, right-angle type; type b, acute-angle type; and type c, complex type). In group A, type a accounted for 57.9% and was significantly more frequent compared with the other types (type b, 32.4%; type c, 5.6%). In group B, type b accounted for 60.8%, being significantly more frequent compared with the other types (type a, 29.4%; type c, 7.2%). Subjective symptoms, preoperative complications (e.g., liver dysfunction and acute pancreatitis), pancreatic stone, and pancreatic duct morphological abnormality were significantly more frequent in group A. However, the amylase levels in the bile and gallbladder were significantly higher in group B, and the presence of gallstone and morphological abnormality of the gallbladder was significantly more frequent in group B. The occurrence rate of cancer in the biliary tract was 10.6% in group A and 37.9% in group B, being significantly higher in group B. In group A, cancer of the extrahepatic bile duct was seen in 33.6% and cancer of the gallbladder was seen in 64.9%, but gallbladder cancer was present significantly more frequently in the patients with diffuse or cylindrical dilatation, and bile duct cancer was present significantly more frequently in the patients with cystic dilatation. In group B, 93.2% of the patients had gallbladder cancer, and bile duct cancer was found in as few as 6.8%. Against this background Japanese surgeons regard cholecystectomy, resection of the extrahepatic bile duct, and hepaticojejunostomy as standard operations for PBM with dilatation of the bile duct. However, opinion on whether or not the bile duct should be removed in the treatment of PBM without dilatation of the bile duct has been divided among Japanese surgeons. A randomized controlled trial is necessary.

A rare case of pancreaticobiliary maljunction (PBM) without dilatation of the biliary tract (DBT) associated with gallbladder carcinoma is described herein. A 62-year-old European woman with a long history of right upper abdominal pain was diagnosed as having PBM without DBT by endoscopic retrograde cholangiopancreatography and other examinations. Excision of the gallbladder and biliary duct with a Roux-en-Y hepaticojejunostomy was performed, and subsequent pathological examination of the surgical specimen showed a well differentiated adenocarcinoma of the gallbladder. She had no clinical symptoms for 58 months postoperatively. PBM allows reflux of pancreatic juice into the biliary tract. Recent findings support the idea that epithelial hyperplasia plays an important role in gallbladder carcinogenesis with PBM, and also support the concept that gene mutations are involved in the carcinogenesis of biliary epithelium in patients with PBM. For these reasons, we advocate that resection of the extrahepatic biliary tract in PBM patients without bile duct dilatation, rather than cholecystectomy alone, is the treatment of choice for preventing bile duct carcinoma.

It is widely known that pancreaticobiliary maljunction (PBM), an anomalous arrangement of the pancreaticobiliary ductal system, is frequently associated with biliary tract cancer in patients with or without bile duct dilatation. In 1985, we surveyed patients with PBM who had been operated on at 133 Japanese institutions. A close relationship was shown between biliary tract carcinogenesis and PBM, according to the type of maljunction and age distribution: PBM patients with cystic dilatation had a high risk of bile duct cancer, even in those who were young (aged less than 20 years); the incidence of gallbladder cancer increased markedly in PBM patients over 40 years old with cystic dilatation, while it gradually increased with age in the PBM patients without cystic dilatation. Therefore, we recommend surgical treatment for patients with PBM even if they have no symptoms.

To investigate the molecular mechanisms of the high incidence of carcinogenesis in the biliary epithelium of patients with pancreaticobiliary maljunction, we examined p53 gene mutations, loss of heterozygosity of p53, and overexpression of p53 gene product in the cancerous and noncancerous biliary epithelium of 27 patients with pancreaticobiliary maljunction. Mutations of the p53 gene were examined by polymerase chain reaction-single strand conformation polymorphism and a direct sequencing method. Loss of heterozygosity of the p53 gene was determined using a double-targeted fluorescence in situ hybridization method. Expression of p53 gene product was examined using immunohistochemical staining. Mutations of the p53 gene were found in 4 of 5 biliary carcinomas (80%) and in 10 of 26 noncancerous biliary lesions (38.5%). Point mutations of the p53 gene were detected at codons 207, 212, and 217 on exons 5 through 8. The incidence of p53 gene mutations on exons 5, 6, 7, and 8 was 12. 9%, 36.4%, 0.0%, and 13.8%, respectively. Loss of heterozygosity of p53 was shown in 72% of the cells obtained from the cancerous lesion, and in an average of 14% obtained from the noncancerous lesions. Overexpression of p53 protein was found in 57.1% of carcinoma, and in 31.3% of the noncancerous lesions. These results suggest that p53 gene mutations are involved in the carcinogenesis of biliary epithelium in patients with pancreaticobiliary maljunction.

The embryogenesis of pancreaticobiliary maljunction is inferred from the embryogenesis of duodenal atresia. The epithelial cells of the duodenum begin to proliferate and completely plug the lumen, but a process of vacuolation recanalizes the duodenum. Recanalization of the common duct frequently appears with two lumina and openings into the duodenum with two orifices. These two major canals create a narrow segment of the duodenum and this narrow zone is the area in the duodenum that is most prone to faulty recanalization and atresia formation. A bifid biliary system inserts at blind upper and lower pouches of the duodenum, and the common bile duct inserts in a Y fashion. The common bile duct inserts at the stenotic segment, and the end result is a T-shaped formation in patients with duodenal stenosis. During the development of the bile duct, abnormal fusion may occur between the bile duct and branches of the right ventral pancreatic duct. The site in the bile duct where a branch of the pancreatic duct joins is likely to develop atresia due to disturbance of the recanalization process, as seen in duodenal atresia. Severe impairment of vacuolation causes divided atretic bile duct at the site where the pancreatic duct inserts in a Y-fashion into the upper and lower bile duct. Moderate impairment of vacuolation causes a stenosis at the site where the pancreatic duct inserts in a T-shape, with a moderate dilatation of the bile duct.