Papillary carcinoma of the extrahepatic bile duct: characteristic features and implications in surgical treatment

Intraductal papillary neoplasm of the bile duct with metachronous development in the downstream bile duct after radical resection

We report a case of intraductal papillary neoplasms of the bile duct (IPNB) that metachronously developed twice in the downstream bile duct after radical resection. The first lesion was located in the left intrahepatic bile duct, the second lesion in the perihilar bile duct, and the third lesion in the distal bile duct. All lesions were IPNBs with associated invasive carcinoma (pancreatobiliary type). The depth of invasion was to the Glisson's capsule in the first lesion, to the subserosa in the second lesion, and to the fibromuscular layer in the third lesion, without lympho-vascular/perineural invasion and lymph-node metastasis. These were resected radically and had no biliary intraepithelial neoplasia and hyperplasia in the surrounding mucosa. In immunohistochemical examination, each lesion showed a different pattern. Although the downstream occurrence suggests intrabiliary dissemination, the mechanism of these metachronous developments may be multicentric. A literature review revealed that most metachronous cholangiocarcinomas have a grossly papillary appearance and tend to arise downstream. Our findings suggest that IPNB may develop metachronously in the residual bile duct after radical surgery, which may assist in early detection.

Intraductal Papillary Neoplasm of Bile Duct: Updated Clinicopathological Characteristics and Molecular and Genetic Alterations

Intraductal papillary neoplasm of the bile duct (IPNB), a pre-invasive neoplasm of the bile duct, is being established pathologically as a precursor lesion of invasive cholangiocarcinoma (CCA), and at the time of surgical resection, approximately half of IPNBs show stromal invasion (IPNB associated with invasive carcinoma). IPNB can involve any part of the biliary tree. IPNB shows grossly visible, exophytic growth in a dilated bile duct lumen, with histologically villous/papillary neoplastic epithelia with tubular components covering fine fibrovascular stalks. Interestingly, IPNB can be classified into four subtypes (intestinal, gastric, pancreatobiliary and oncocytic), similar to intraductal papillary mucinous neoplasm of the pancreas (IPMN). IPNBs are classified into low-grade and high-grade based on lining epithelial features. The new subclassification of IPNB into types 1 (low-grade dysplasia and high-grade dysplasia with regular architecture) and 2 (high-grade dysplasia with irregular architecture) proposed by the Japan–Korea pathologist group may be useful in the clinical field. The outcome of post-operative IPNBs is more favorable in type 1 than type 2. Recent genetic studies using next-generation sequencing have demonstrated the existence of several groups of mutations of genes: (i) IPNB showing mutations in KRAS, GNAS and RNF43 belonged to type 1, particularly the intestinal subtype, similar to the mutation patterns of IPMN; (ii) IPNB showing mutations in CTNNB1 and lacking mutations in KRAS, GNAS and RNF43 belonged to the pancreatobiliary subtype but differed from IPMN. IPNB showing mutation of TP53, SMAD4 and PIK3CA might reflect complicated and other features characterizing type 2. The recent recognition of IPNBs may facilitate further clinical and basic studies of CCA with respect to the pre-invasive and early invasive stages.

Planned limited resection of the extrahepatic bile duct in a case of intraductal papillary neoplasm of the bile duct based on preoperative examinations

Intraductal papillary neoplasm of the bile duct (IPNB) is defined as a non-invasive malignancy; however, since there are disparities in its histological diagnosis, the operative strategy for typical IPNB has not yet been established. A 69-year-old male was diagnosed with a bile duct mass lesion at the confluence of the cystic duct by ultrasonography without clinical symptoms. Liver functional parameters and tumor markers were within normal ranges. Computed tomography showed an enhanced tumor with no findings of ductal invasion or node metastasis. The tumor was exposed in the hepatic duct lumen and biopsy via SpyGlass DS cholangiography revealed that it was a low-grade papillary lesion, indicating type 1 IPNB. Under preoperative diagnostic modalities, limited resection of the extrahepatic bile duct with D2 lymphadenectomy was planned and R0 resection was achieved. The postoperative histological diagnosis was type 1 IPNB without node metastasis. The postoperative course was uneventful and a good prognosis is expected at this stage. In the field of biliary surgery, although extended resection is generally performed for bile duct carcinomas, satisfactory limited surgical resection is possible for type 1 IPNB with lower malignant behavior.

Comparison of the Clinicopathologic Characteristics of Intraductal Papillary Neoplasm of the Bile Duct according to Morphological and Anatomical Classifications

BACKGROUND

Intraductal papillary neoplasm of the bile duct (IPNB) is a recently defined entity and its clinical characteristics and classifications have yet to be established. We aimed to clarify the clinical features of IPNB and determine the optimal morphological classification criteria.

METHODS

From 2003 to 2016, 112 patients with IPNB who underwent surgery were included in the analysis. After pathologic reexamination by a specialized biliary-pancreas pathologist, previously suggested morphological and anatomical classifications were compared using the clinicopathologic characteristics of IPNB.

RESULTS

In terms of histologic subtypes, most patients had the intestinal type (n = 53; 48.6%) or pancreatobiliary type (n = 33; 30.3%). The simple "modified anatomical classification" showed that extrahepatic IPNB comprised more of the intestinal type and tended to be removed by bile duct resection or pancreatoduodenectomy. Intrahepatic IPNB had an equally high proportion of intestinal and pancreatobiliary types and tended to be removed by hepatobiliary resection. Morphologic classifications and histologic subtypes had no effect on survival, whereas a positive resection margin (75.9% vs. 25.7%; P = 0.004) and lymph node metastasis (75.3% vs. 30.0%; P = 0.091) were associated with a poor five-year overall survival rate. In the multivariate analysis, a positive resection margin and perineural invasion were important risk factors for survival.

CONCLUSION

IPNB showed better long-term outcomes after optimal surgical resection. The "modified anatomical classification" is simple and intuitive and can help to select a treatment strategy and establish the proper scope of the operation.

Gallbladder mucosal lesions associated with high biliary amylase irrespective of pancreaticobiliary maljunction

BACKGROUND

Previous studies have focused on the presence of reflux in selected cohorts with pancreaticobiliary maljunction (PBM), but little is known regarding the wider incidence of occult reflux and associated mucosal changes. We aimed to correlate gallbladder mucosal abnormalities with objective evidence of PBM and occult pancreaticobiliary reflux (PBR) in an Australian population undergoing cholecystectomy.

METHODS

Patients undergoing cholecystectomy between September 2010 and September 2012 were eligible for inclusion. Demographic and pre-operative clinical data were collated and entered into a pre-defined database. Operative cholangiograms were routinely performed and the presence of PBM noted. Gallbladder bile samples were analysed for bilirubin (<20 µmol/L), amylase (<100 U/L) and lipase (<70 U/L) levels. Evidence of PBR was correlated with gallbladder mucosal findings.

RESULTS

A total of 305 cholecystectomies were performed for biliary colic (73%), choledocholithiasis (9%), cholecystitis (8.4%) and pancreatitis (6.4%). A total of 12.7% had cholangiographic evidence of PBM and 11.9% possessed gallbladder mucosal changes. Overall, 7.7% had increased biliary amylase, which was associated with significantly higher rates of gallbladder intestinal metaplasia (33% versus 8.6%; P = 0.012). Elevated biliary amylase was also higher in patients with prior pancreatitis (P = 0.02) or choledocholithiasis (P < 0.01). The presence of PBM did not predict for the presence of PBR.

CONCLUSION

PBR is associated with an increased frequency of gallbladder mucosal metaplasia, irrespective of the presence of PBM. Objectively identified reflux represents an additional indication for cholecystectomy but the long-term consequences for extra-hepatic biliary malignancy remain unknown and warrant further investigation. Methods of objectively identifying PBR pre-operatively require further investigation.

Biliary carcinogenesis in pancreaticobiliary maljunction

Pancreaticobiliary maljunction (PBM) is a congenital malformation in which the pancreatic and bile ducts join anatomically outside the duodenal wall. Because of the excessive length of the common channel in PBM, sphincter action does not directly affect the pancreaticobiliary junction, which allows pancreatic juice to reflux into the biliary tract. According to the results of a nationwide survey, bile duct and gallbladder cancers were found in 6.9 and 13.4 % of adult patients with congenital biliary dilatation, respectively, and in 3.1 and 37.4 % of those with PBM without biliary dilatation, respectively. Biliary tract cancers develop about 15-20 years earlier in patients with PBM than in individuals without PBM; they sometimes develop as double cancers. Carcinogenesis is strongly associated with stasis of bile intermingled with refluxed pancreatic juice. Epithelial cells in the biliary tract of PBM patients are under constant attack from activated pancreatic enzymes, increased secondary bile acids, or other mutagens. This can result in hyperplastic change with increased cell proliferation activity, and in turn, oncogene and/or tumor suppressor gene mutations in the epithelia, leading to the biliary tract carcinogenesis. The carcinogenesis of biliary tract cancer accompanying PBM is considered to involve a hyperplasia-dysplasia-carcinoma sequence induced by chronic inflammation caused by the reflux of pancreatic juice into the biliary tract, which differs from the adenoma-carcinoma sequence or the de novo carcinogenesis associated with biliary tract cancers in the population without PBM. Patients with a relatively long common channel have a similar, albeit slightly lower, risk for gallbladder cancer compared with PBM patients.

A variant of multicystic biliary hamartoma presenting as an intrahepatic cystic neoplasm

A rare case of an intrahepatic multicystic tumor is described. A 26-year-old man visited our hospital because of abdominal discomfort. Contrast-enhanced computed tomography and magnetic resonance cholangiopancreatography revealed a 10 × 7 cm multicystic tumor of the bile duct in the right side of the liver. The gross appearance of the tumor resembled an intraductal papillary neoplasm of the bile duct, and right hepatectomy with regional lymphadenectomy was performed. Histologically, these cystic lesions were composed of variably and irregularly dilated duct structures lined by columnar epithelium resembling bile duct lining. There were no atypical cells and no papillary growth of the epithelial cells. Interestingly, the dilated ducts contained inspissated bile, and the inter-cystic parenchyma contained variable but irregularly distributed and hamartomatous hepatic parenchyma with an abnormal lobular pattern. Though it had atypical features of a hamartoma in some aspects (age, smooth muscle), this case could finally be regarded as a variant of multicystic biliary hamartoma.

A case of biliary cystic tumor with repeated hemobilia

Intraductal papillary neoplasm of the bile duct (IPNB) is classified as a biliary cystic tumor with a tendency of causing obstruction. Neoplastic cases involving hemobilia are rarely reported. We herein describe a case of biliary cystic tumor with repeated hemobilia. A 57-year-old woman was histologically diagnosed with cavernous hemangioma. During the follow-up period after transcatheter arterial embolization (TAE), she experienced repeated hemobilia, and multiple other TAE sessions were performed for hemostasis. She was referred to our hospital 8 years after the first surgery owing to a growing tumor. Histopathological examination after extended right hepatectomy and caudate lobectomy indicated IPNB with an associated invasive carcinoma. Six months thereafter, computed tomography revealed a recurrent liver tumor and a nodule in the abdominal cavity. She died 36 months after the second surgery, despite chemotherapy. Our experience suggests that IPNB should be considered during differential diagnosis of dilated hepatobiliary tumors with hemobilia.

Pancreaticobiliary maljunction and biliary cancer

Pancreaticobiliary maljunction (PBM) is a congenital malformation in which the pancreatic and bile ducts join anatomically outside the duodenal wall. Japanese clinical practice guidelines on how to deal with PBM were made in 2012, representing a world first. According to the 2013 revision to the diagnostic criteria for PBM, in addition to direct cholangiography, diagnosis can be made by magnetic resonance cholangiopancreatography (MRCP), 3-dimensional drip infusion cholangiography computed tomography, endoscopic ultrasonography (US), or multiplanar reconstruction images by multidetector row computed tomography. In PBM, the common channel is so long that sphincter action does not affect the pancreaticobiliary junction, and pancreatic juice frequently refluxes into the biliary tract. Persistence of refluxed pancreatic juice injures epithelium of the biliary tract and promotes cancer development, resulting in higher rates of carcinogenesis in the biliary tract. In a nationwide survey, biliary cancer was detected in 21.6% of adult patients with congenital biliary dilatation (bile duct cancer, 32.1% vs. gallbladder cancer, 62.3%) and in 42.4% of PBM patients without biliary dilatation (bile duct cancer, 7.3% vs. gallbladder cancer, 88.1%). Pathophysiological conditions due to pancreatobiliary reflux occur in patients with high confluence of pancreaticobiliary ducts, a common channel ≥6 mm long, and occlusion of communication during contraction of the sphincter. Once the diagnosis of PBM is established, immediate prophylactic surgery is recommended. However, the surgical strategy for PBM without biliary dilatation remains controversial. To detect PBM without biliary dilatation early, MRCP is recommended for patients showing gallbladder wall thickening on screening US under suspicion of PBM.

Pancreaticoduodenectomy for secondary periampullary cancer following extrahepatic bile duct cancer resection

PURPOSE

This study addressed the feasibility and effect of surgical treatment of metachronous periampullary carcinoma after resection of the primary extrahepatic bile duct cancer. The performance of this secondary curative surgery is not well-documented.

METHODS

We reviewed, retrospectively, the medical records of 10 patients who underwent pancreaticoduodenectomy (PD) for secondary periampullary cancer following extrahepatic bileduct cancer resection from 1995 to 2011.

RESULTS

The mean age of the 10 patients at the second operation was 61 years (range, 45-70 years). The primary cancers were 7 hilar cholangiocarcinomas, 2 middle common bile duct cancers, and one cystic duct cancer. The secondary cancers were 8 distal common bile duct cancers and 2 carcinomas of the ampulla of Vater. The second operations were 6 Whipple procedures and 4 pylorus-preserving pancreaticoduodenectomies. The mean interval between primary treatment and metachronous periampullary cancer was 20.6 months (range, 3.4-36.6 months). The distal resection margin after primary resection was positive for high grade dysplasia in one patient. Metachronous tumor was confirmed by periampullary pathology in all cases. Four of the 10 patients had delayed gastric emptying (n = 2) or pancreatic fistula (n = 2) after reoperation. There were no perioperative deaths. Median survival after PD was 44.6 months (range, 8.5-120.5 months).

CONCLUSION

Based on the postoperative survival rate, PD may provide an acceptable protocol for resection in patients with metachronous periampullary cancer after resection of the extrahepatic bile duct cancer.

Classifying extrahepatic bile duct metachronous carcinoma by de novo neoplasia site

Extrahepatic bile duct (EHBD) cancer may occur metachronously, and these cancers are resectable with a favorable prognosis. We aimed to identify the pattern of metachronous EHBD cancer. We classified the cases of metachronous EHBD cancer reported in the literature thus far and investigated two new cases of metachronous EHBD cancer. A 70-year-old female underwent R0 bile duct resection for a type 1 Klatskin tumor (pT1N0M0). A 70-year-old male patient underwent R0 bile duct resection for a middle bile duct cancer (pT2N1M0). Imaging studies of both patients taken at 14 and 24 mo after first surgery respectively revealed a metachronous cholangiocarcinoma that required pancreaticoduodenectomy (PD). Histopathology of the both tumors after PD revealed cholangiocarcinoma invading the pancreas (pT3N0M0). Both patients have been free from recurrence for 6 years and 16 mo respectively after the second surgery. Through a review of the literature on these cases, we classified the pattern of metachronous EHBD cancer according to the site of de novo neoplasia. The proximal remnant bile duct was most commonly involved. Metachronous EHBD cancer should be distinguished from an unresectable recurrent tumor. Classifying metachronous EHBD cancer may be helpful in identifying rare metachronous tumors.

Metachronous biliary carcinoma with intraductal pancreatic adenocarcinoma 13 years after curative resection of hilar bile duct cancer

We report a case of a 68-year-old woman with metachronous bile duct cancer and a pancreatic adenocarcinoma. She had undergone extended left hepatic lobectomy for hilar bile duct carcinoma. However, when she was admitted to our hospital 13 years later for an annual follow-up, abdominal CT revealed a mass in the dilated remnant of her lower bile duct. This was diagnosed as a second primary tumour, a pancreaticoduodenectomy was performed and 15 months after the second operation, she remains recurrence-free. Nineteen cases of patients with metachronous bile duct carcinomas were identified in the literature and have been reviewed.

Impact of macroscopic morphology, multifocality, and mucin secretion on survival outcome of intraductal papillary neoplasm of the bile duct

BACKGROUND

Intraductal papillary neoplasms of the bile duct (IPNB) are relatively rare disease with favorable prognosis. The authors investigated clinicopathologic characteristics and prognostic factors of IPNB in viewpoint of macroscopic morphology and multiplicity.

METHODS

Data were collected from 84 patients who underwent surgery at Seoul National University Hospital with diagnosis of IPNB from 2000 to 2009.

RESULTS

Median follow-up was 41.8 months and 75 (89.3 %) had invasive cancer. Tumors were confined to the bile duct in 45 patients (53.6 %) and 8 (9.5 %) had lymph node metastasis. Curative resection was achieved in 70 patients (89.3 %). Mucin secretion was identified in 23 (28.0 %) and 43 (51.2 %) had multiple tumors. Multiple IPNB had poor prognosis compared with single IPNB (5-year survival rate 50.7 vs. 85.9 %; P = 0.011). Positive resection margin (P = 0.046) and multiplicity (P = 0.038) were independent prognostic factors of IPNB after multivariate analysis. Mucin secretion had no impact on survival outcome (P = 0.595). The disease-free survival rate was significantly lower in multiple IPNB compared with single IPNB (5-year disease free survival rates 36.1 vs. 74.1 %; P = 0.026).

CONCLUSION

Multiplicity is a common feature of IPNB and has a negative impact on prognosis. Current WHO classification for IPNB needs consideration for macroscopic morphology and multiplicity considering its prognostic impact of IPNB.

Intrahepatic and extrahepatic intraductal papillary neoplasms of bile duct

There has been an increase in the number of reported cases of biliary neoplasm of the hepatobiliary system characterized by markedly dilated and multifocal papillary epithelial lesions of the bile ducts or cystic biliary lesions with or without mucin secretion, and mucinous lesions or tumors, possibly due to recent advances in radiological diagnosis. This lesion of the bile duct is believed to show a better clinical course than non-papillary biliary neoplasm. Therefore, the early recognition and treatment is important. We report two cases of intrahepatic and extrahepatic intraductal papillary neoplasm of the bile duct that were completely resected.

Japanese clinical practice guidelines for pancreaticobiliary maljunction

There have been no clinical guidelines for the management of pancreaticobiliary maljunction (PBM). The Japanese Study Group on Pancreaticobiliary Maljunction (JSPBM) has proposed to establish clinical practice guidelines on how to deal with PBM, with the support of the Japan Biliary Association (JBA). Because the body of evidence-based literature is relatively small, we decided to create guidelines based on the consensus of experts, using the medical literature for reference. A total of 46 clinical questions (CQs) were considered by the members of the editorial committee responsible for the guidelines. The CQs covered distinct aspects of PBM: (1) Concepts and Pathophysiology (10 CQs); (2) Diagnosis (10 CQs); (3) Pancreatobiliary complications (9 CQs); and (4) Treatments and prognosis (17 CQs). Statements and comments for each CQ were prepared by the guidelines committee members and collaborating partners. The CQs were completed after review by members of the editorial committee, meetings of this committee, public comments on the homepages of the JSPBM and the JBA, public hearings, and assessment and approval by the guidelines evaluation board. PBM includes cases where the bile duct is dilated (PBM with biliary dilatation) and those in which it is not (PBM without biliary dilatation). In these guidelines, PBM with biliary dilatation is defined as being identical to congenital biliary dilatation of Todani type I (except for type Ib) and type IV-A, both of which are accompanied by PBM in almost all cases. These guidelines are created to provide assistance in the clinical practice of PBM management; their contents focus on clinical utility, and they include general information on PBM to make this disease more widely recognized.

Surgical outcomes of multicentric adenocarcinomas of the biliary tract

OBJECTIVE

In comparison to single biliary cancers, distinct features of biliary multicentric adenocarcinomas are not yet clear.

METHODS

From July 1992 to July 2009, 393 patients underwent surgery for cancers of the biliary tract at the National Cancer Center Hospital East, Kashiwa, Japan. Clinicopathological characteristics and surgical outcomes of multicentric biliary adenocarcinoma were compared with those of single cancers.

RESULTS

During the period, 10 cases (2.5%) with multicentric cancer (6 synchronous and 4 metachronous cancers) were found among 393 cases of biliary cancer. Pathologically, compared with single cancers, multicentric adenocarcinomas were more likely to be early cancers and to be papillary carcinomas with both superficial epithelial tumor spread and extensive dysplastic epithelium, but were less likely to have lymph node metastases (P < 0.01). The proportion of multicentric cancers among early papillary cancers was high (9/24, 37.5%). Clinically, no recurrences were detected in lymph nodes, peritoneum or distant organs, but one recurrence in the remnant bile duct. Only one patient died from cancer progression. The overall survival of patients with multicentric adenocarcinomas was statistically the same as that of single cancers (median survival: 69 vs. 30 months, P = 0.47).

CONCLUSIONS

Multicentric adenocarcinomas of the biliary tract have distinct features compared with single cancers.

Characteristics of bile duct carcinoma with superficial extension in the epithelium

BACKGROUND

Longitudinal tumor extension from the main tumor involves intramural or superficial spread along the bile duct, which influences surgical curability. Identifying the range of superficial extension is difficult by preoperative imaging. To clarify specific characteristics of bile duct carcinoma (BDC) with superficial extension of epithelium in the bile duct, we examined clinicopathologic features and patient outcomes in BDC patients with or without superficial extension who underwent surgical resection.

METHODS

Between 1994 and 2008, we retrospectively examined clinicopathologic findings and outcomes for 42 BDC patients who underwent surgical resection and divided them into two groups: (1) superficial extension (SE) group (n = 10); and (2) non-SE group (n = 32).

RESULTS

In terms of macroscopic growth of the main tumor, the papillary type was more common in the SE group than in the non-SE group, whereas the nodular type was dominant in the non-SE group. The prevalence of cancer-positive findings at the cut end of the bile duct was higher in the SE group. Portal vein invasion was not observed in the SE group, and the prevalence of regional lymph node metastasis was significantly greater in the non-SE group than in the SE group. No patients died of cancer in the SE group, who tended to show better survival than the non-SE group.

CONCLUSIONS

The present results suggest that a good prognosis may be achieved in BDC patients with SE when complete resection is accomplished.

A case of intraductal papillary neoplasm of the bile duct with stromal invasion

Intraductal papillary neoplasm of the bile duct (IPNB) represents biliary papillary tumors mainly growing and is considered to be of relatively low-grade malignancy. Here we report a case of IPNB in whom the poorly differentiated component deeply infiltrated the bile duct wall. A 77-year-old male had an invasive carcinoma of the bile duct 3 cm in size. He underwent right hemihepatectomy with combined resection of the extrahepatic bile duct. Papillary growing tumor was observed in the common bile duct and the right posterior Glisson's pedicle was invaded. Histologic finding showed papillary adenocarcinoma in the surface layer superficially extending to the epithelium of the surrounding bile duct. In the subserosal layer, the tumor represented poorly differentiated adenocarcinoma. The tumor was diagnosed as invasive bile duct carcinoma arising from IPNB.

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.