Proposal of histological criteria for intraepithelial atypical/proliferative biliary epithelial lesions of the bile duct in hepatolithiasis with respect to cholangiocarcinoma: preliminary report based on interobserver agreement

Clinical implications of pediatric biliary intraepithelial neoplasia diagnosed from a choledochal cyst specimen

BACKGROUND

Biliary intraepithelial neoplasia (BilIN), a noninvasive precursor of cholangiocarcinoma, can manifest malignant transformation. Since cholangiocarcinoma (CCA) may progress due to chronic inflammation in the bile ducts and gallbladder, choledochal cysts are considered a precursor to CCA. However, BilIN has rarely been reported in children, to date.

METHODS

We reviewed medical records of patients (< 18 years of age, n = 329) who underwent choledochal cyst excision at Asan Medical Center from 2008 to 2022. BilIN was diagnosed in 15 patients. Subsequent analyses were performed of the demographics, surgical procedures, clinical course, and outcomes in these patients. Subgroup analysis and multivariate logistic regression test were performed to identify factors influencing BilIN occurrence.

RESULTS

The mean age of the patients included in our study was 40.1 ± 47.6 months. In 15 patients, BilIN of various grades was diagnosed. Todani type I was prevalent in 80% of the patients. The median age at surgery was 17 months. During a mean follow-up of 63.3 ± 94.0 months, no adverse events such as stone formation in the remnant intrapancreatic common bile duct and intrahepatic duct or cholangiocarcinoma were observed, indicating a favorable outcome until now.

CONCLUSIONS

The potential progression of choledochal cysts to BilIN in children was demonstrated. These results could underscore the importance of early and comprehensive excision of choledochal cysts, including resection margins for associated lesions and more thorough postoperative surveillance in patients with or at risk of BilIN.

Platynosomum (Trematoda: Dicrocoeliidae) infection in barn owls (Tyto alba) in Northeastern Brazil

Platynosomum spp. are parasites that inhabit the gallbladder and bile ducts of various mammals and birds worldwide. Most studies of Platynosomum spp. in birds focus on the observation and morphological characterization of the parasite through parasitological or molecular examinations, with scarce literature describing anatomopathological alterations, mainly histopathological. We report the case of a male barn owl infected with Platynosomum spp.. At necropsy, the barn owl showed dilation with parasites and fibrosis of the intrahepatic bile ducts and gallbladder. Microscopically, it was possible to identify trematodes in the bile ducts associated with a lymphoplasmacytic inflammatory infiltrate. The morphological structures of the worms were described on histopathology and direct examination. The presence of parasitism that is usually cosmopolitan in wild animals represents a risk to the biodiversity of fauna in the region, as well as a warning about the spread and maintenance of the biological cycle of the worm in humans and domestic animals.

Bile ductal mucosal dysplasia is a possible risk factor for adenocarcinoma in patients with adenomyomatous hyperplasia of the Vaterian system: a single-centre study from China

BACKGROUND

The relationship between adenomyomatous hyperplasia of the Vaterian system(AV) and cancer is unclear, some reports suggest that AV is often combined with mucosal glandular dysplasia, but it is not clear whether mucosal glandular dysplasia is a risk factor for carcinogenesis of AV. The aim of this study was to retrospective analysis of role of ductal glandular dysplasia as a risk factor in the development of carcinoma in AV.

METHODS

A total of 328 cases who underwent surgery with a final pathological diagnosis of adenomyomatous hyperplasia (AH) in the Chinese PLA General Hospital in BeiJing, China, between January 2005 and December 2021 were retrospectively collected. There were Seventeen cases(5%) in which the lesions were located in the common bile duct as well as the ampulla of Vater, and their clinical (age, sex, etc.), imaging (cholelithiasis, etc.) and pathological data (mucosal glandular dysplasia, etc.) were collected. Clinical data and pathological features of AV with or without mucosal glandular dysplasia were analyzed.

RESULTS

There were 17 out of 328 cases of AH occurring in the Vaterian system (5%). Three of seventeen AV cases were associated with carcinoma (18%). Of three cases, two (12%) with the tumor lesions in the mucosal glands adjacent to the AH (biliary tract cancer and ampullary cancer), and one (6%) with carcinoma developed from AH itself in the ampulla of Vater. All carcinomas had adenomyomatous hyperplasia with nearby mucosal glandular dysplasia (MGD). The percentage of BTC or AC was higher in patients with concurrent AH and MGD compared to AH patients without MGD. The results show tendency toward statistical significance (P = 0.082). This difference was more obvious among AH with severe dysplasia compared to adenomyomatous hyperplasia with mild-moderate dysplasia (P = 0.018).

CONCLUSION

This study is the first to find that AV is associated with biliary tract cancer and ampullary cancer. In AV, the mucosal glandular dysplasia may be a risk factor for the development of malignancy. The underlying mechanism for carcinogenesis of AV could be AH itself or its secretions stimulating mucosal glands hyperplasia, then mucosal glands dysplasia. AV may be a precancerous lesion.

INTRAHEPATIC BILIARY PROLIFERATIONS: HISTOPATHOLOGY AND POTENTIAL IMMUNOHISTOCHEMICAL MARKERS

•Intrahepatic biliary proliferations represent a spectrum varying from reactive to malignant entities. •Clinical and imaging patterns may be similar, requiring histopathological and immunohistochemistry for precise diagnosis. Intrahepatic biliary proliferations represent a spectrum from reactive (ductular reaction, some with atypical architecture), hamartomatous (von Meyenburg complex), benign (bile duct adenoma) and precursor/borderline entities (biliary intraepithelial neoplasia, intraductal papillary neoplasm of the bile duct) to fully malignant (cholangiocarcinoma) neoplasms. Clinical pictures and even imaging patterns may be similar, requiring refined studies aiming at histopathological and immunohistochemistry for more precise diagnosis, essential for correct patient management. This article discusses updated concepts and definitions of most relevant entities aiming more specifically at the differential diagnosis in practice, focusing on morphology and immunohistochemistry, with a discussion of potential markers to help distinguishing between benign and malignant lesions.

Bile duct dysplasia and associated invasive carcinoma: clinicopathological features, diagnosis, and practical challenges

Cholangiocarcinoma represents the second most frequent type of primary liver cancer that develops through a multistep histopathologic sequence. Dysplasia in the biliary tract epithelium is a precursor lesion of cholangiocarcinoma. This review provides a practical overview of bile duct dysplasia in relation to invasive carcinoma, covering clinicopathological features, diagnostic criteria, differential diagnosis, useful testing modalities, and challenges in daily practice. The key features of biliary intraepithelial neoplasia, intraductal papillary neoplasm, intraductal tubulopapillary neoplasm, and mucinous cystic neoplasm are described. Important differential diagnoses are included. Common pitfalls in histopathologic interpretation of bile duct biopsies and frozen sections are discussed.

Role of DNA Flow Cytometry in the Diagnosis of Malignancy in Bile Duct Biopsies Using Paraffin-Embedded Tissue

OBJECTIVES

Histopathologic evaluation of bile biopsies for biliary strictures is frequently challenging and is affected by interobserver disagreement. Reliable ancillary tests that can help differentiate benign from malignant are not available. This study aimed to evaluate whether DNA content abnormalities detected by flow cytometry on formalin-fixed, paraffin-embedded (FFPE) tissue can help differentiate benign/reactive, dysplastic from malignant cell populations in bile duct biopsies.

METHODS

We performed DNA flow cytometry on 30 FFPE bile duct biopsies in 5 well-defined diagnostic categories: (1) negative for dysplasia (NED), (2) low-grade dysplasia (LGD), (3) high-grade dysplasia (HGD), (4) carcinoma (CA), and (5) indefinite for dysplasia (IND).

RESULTS

Abnormal DNA content was detected in 0 NED, 5 LGD (62.5%), 2 HGD (33.3%), 3 CA (60%), and 4 IND (80%) samples. As a diagnostic marker, the estimated sensitivity, specificity, positive predictive value, and negative predictive value were 63%, 100%, 100%, and 50%, respectively, for diagnosing HGD or CA.

CONCLUSIONS

DNA flow cytometry analysis is a useful ancillary test for the interpretation of bile duct biopsies. DNA content abnormalities, when correlated with histologic findings, will not only help confirm the morphologic impression but also identify patients who are at a higher risk of developing malignancy.

Precursor Lesions of Gallbladder Carcinoma: Disease Concept, Pathology, and Genetics

Understanding the pathogenesis and carcinogenesis of gallbladder adenocarcinoma is important. The fifth edition of the World Health Organization’s tumor classification of the digestive system indicates three types of preinvasive neoplasm of the gallbladder: pyloric gland adenoma (PGA), biliary intraepithelial neoplasia (BilIN), and intracholecystic papillary neoplasm (ICPN). New terminologies have also been introduced, such as intracholecystic papillary-tubular neoplasm, gastric pyloric, simple mucinous type, and intracholecystic tubular non-mucinous neoplasm (ICTN). Pancreatobiliary maljunction (PBM) poses a markedly high risk for bile duct carcinoma, which was analyzed and investigated mainly by Asian researchers in the past; however, recent studies have clarified a similar significance of biliary carcinogenesis in Western countries as well. In this study, we reviewed and summarized information on three gallbladder neoplastic precursors, PGA, BilIN, and ICPN, and gallbladder lesions in patients with PBM.

Association of Microbial Dysbiosis with Gallbladder Diseases Identified by Bile Microbiome Profiling

BACKGROUND

Cholecystitis is an important risk factor for gallbladder cancer, but the bile microbiome and its association with gallbladder disease has not been investigated fully. We aimed to analyze the bile microbiome in normal conditions, chronic cholecystitis, and gallbladder cancer, and to identify candidate bacteria that play an important role in gallbladder carcinogenesis.

METHODS

We performed metagenome sequencing on bile samples of 10 healthy individuals, 10 patients with chronic cholecystitis, and 5 patients with gallbladder cancer, and compared the clinical, radiological, and pathological characteristics of the participants.

RESULTS

No significant bacterial signal was identified in the normal bile. The predominant dysbiotic bacteria in both chronic cholecystitis and gallbladder cancer were those belonging to the Enterobacteriaceae family. Klebsiella increased significantly in the order of normal, chronic cholecystitis, and gallbladder cancer. Patients with chronic cholecystitis and dysbiotic microbiome patterns had larger gallstones and showed marked epithelial atypia, which are considered as precancerous conditions.

CONCLUSION

We investigated the bile microbiome in normal, chronic cholecystitis, and gallbladder cancer. We suggest possible roles of Enterobacteriaceae, including Klebsiella, in gallbladder carcinogenesis. Our findings reveal a possible link between a dysbiotic bile microbiome and the development of chronic calculous cholecystitis and gallbladder cancer.

Recognition and pathological features of periampullary region adenocarcinoma with an indeterminable origin

Determination of the primary tumor in periampullary region carcinomas can be difficult, and the pathological assessment and clinicopathological characteristics remain elusive. In this study, we investigated the current recognition and practices for periampullary region adenocarcinoma with an indeterminable origin among expert pathologists through a cognitive survey. Simultaneously, we analyzed a prospective collection of cases with an indeterminable primary tumor diagnosed from 2008 to 2018 to elucidate their clinicopathological features. All cases with pathological indeterminable primary tumors were reported and discussed in a clinicopathological conference to elucidate if it was possible to distinguish the primary tumor clinically and pathologically. From the cognitive survey, over 85% of the pathologists had experienced cases with indeterminable primary tumors; however, 70% of the cases was reported as pancreatic cancer without definitive grounds. Interpretation of the main tumor mass varied, and no standardized method was developed to determine the primary tumor. During a prospective study, 42 of the 392 periampullary carcinoma cases (10.7%) were considered as tumors with a pathological indeterminable origin. After the clinicopathological conferences, 21 (5.4%) remained indeterminable and were considered final indeterminable cases. Histological studies showed that the tumors spread along both the bile duct and main pancreatic duct; this was the most representative finding of the final indeterminable cases. This study is the first to elucidate and recognize the current clinicopathological features of periampullary region adenocarcinomas with an indeterminable origin. Adequate assessment of primary tumors in periampullary region carcinomas will help to optimize epidemiological data of pancreatic and bile duct cancer.

Prognostic implications of the coexisting precursor lesion types in invasive gallbladder cancer

Invasive gallbladder carcinoma (GBC) is preceded by two main types of precursor lesions: intracholecystic papillary-tubular neoplasms (ICPNs) and biliary intraepithelial neoplasias (BilINs). Invasive GBCs with an ICPN component have more favorable prognoses than those without an ICPN component. Some BilINs show a relatively exophytic papillary pattern but do not meet the ICPN criteria; at our institution, we call these papillary neoplasias. To clarify the clinical significance of papillary neoplasia, we herein examined 80 invasive GBCs and classified them into three groups based on the type of preinvasive lesions: those with ICPN (ICPN group, n = 35), those with papillary neoplasia (pap-neoplasia group, n = 13), and those without ICPN/papillary neoplasia (group without ICPN/pap-neoplasia, n = 32). We then compared the prognostic differences and characterized the tumors of each group by determining the immunohistochemical expressions of various biomarkers. The overall survival periods of the ICPN and pap-neoplasia groups were significantly longer than that of the group without ICPN/pap-neoplasia (P < 0.0001, P = 0.0036, respectively). Multivariate analysis revealed that lacking ICPN/papillary neoplasia was independently associated with poor prognosis (P = 0.0007), as were poor differentiation (P = 0.0395), presence of preoperative symptoms (P = 0.0488), and advanced stage (P = 0.0234). Invasive components of the ICPN and pap-neoplasia groups were characterized by higher expressions of p16 and p53 compared with those of the group without ICPN/pap-neoplasia. The prognoses of the invasive GBCs with either papillary neoplasia or ICPN were thus more favorable than those of the invasive GBCs without ICPN/pap-neoplasia. Invasive GBCs with exophytic papillary preinvasive lesions (ICPN and papillary neoplasia) may be biologically different from those without such lesions.

Early Detection of High-grade Biliary Intraepithelial Neoplasia (BilIN-3) in the Cystic Duct Visualized by SpyGlass DS Cholangioscopy

An 84-year-old man was admitted with epigastralgia. Computed tomography showed contrast-enhanced wall thickness in the cystic duct. An endoscopic examination revealed short irregular stricture in the cystic duct, and per-oral cholangioscopy revealed a reddish papillary tumor at the stricture site. Surgical resection revealed high-grade biliary intraepithelial neoplasia (BilIN) at the stricture site of the cystic duct. To our knowledge, this is the first case of a solitary high-grade BilIN epithelium in the cystic duct detected by per-oral cholangioscopy.

Interobserver agreement in pathologic evaluation of bile duct biopsies

Intraductal biopsy is commonly used for preoperative evaluation of the etiology of biliary strictures. Interpretation of intraductal biopsies is frequently challenging. The diagnosis often suffers from interobserver disagreement, which has not been studied in the literature. We sought to assess interobserver concordance in the interpretation of intraductal biopsies. Eighty-five biopsies were retrieved, falling into five diagnostic categories: negative for dysplasia (NED), indefinite for dysplasia (IND), low-grade dysplasia (LGD), high-grade dysplasia (HGD), and carcinoma (CA). Eight gastrointestinal pathologists blindly reviewed all the slides. Agreement among pathologists was analyzed using Fleiss κ and weighted concordance coefficient S∗. A face-to-face consensus/training session was held to discuss the classification criteria, followed by a second round review. The overall interobserver agreement was fair in the first round review (κ = 0.39; S∗ = 0.56) and improved to moderate in the second round review (κ = 0.48; S∗ = 0.69). The agreement before and after consensus meeting was substantial to nearly perfect for CA (κ = 0.65, S∗ = 0.83; and κ = 0.80, S∗ = 0.91), fair for HGD (κ = 0.28, S∗ = 0.69; and κ = 0.40, S∗ = 0.63), and moderate for NED (κ = 0.47, S∗ = 0.50; and κ = 0.47, S∗ = 0.53). Agreement improved from fair to moderate for LGD (κ = 0.36, S∗ = 0.61; and κ = 0.49, S∗ = 0.71) and slight to fair for IND (κ = 0.16, S∗ = 0.51; and κ = 0.33, S∗ = 0.50). Compared with Hollande's fixed specimens, the agreement was higher in almost all diagnostic categories in formalin-fixed biopsies. Overall, interobserver concordance was improved after a consensus/training session. Interobserver reproducibility was high at the end of the diagnostic spectrum (CA) but fair to moderate for other diagnostic categories.

Synchronous Double Bile Duct Cancers with Distinct Genetic Features

A 69-year-old man was referred to our hospital because of appetite loss. Imaging showed a nodular tumor in the perihilar bile duct and a second flat lesion in the distal bile duct. Right hepatopancreaticoduodenectomy was performed, and the histopathological findings demonstrated that the perihilar and distal lesions were moderately and poorly differentiated adenocarcinoma, respectively, and anatomically separated. Furthermore, the resected specimens showed no pancreaticobiliary maljunction. Histological and TP53 gene analyses in a rare case of synchronous double bile duct cancers suggest that there are various genetic pathways through which bile duct cancer develops, highlighting the complexity of its pathogenesis.

Precursors to Cholangiocarcinoma

Cancers of the biliary tract include intra- and extrahepatic cholangiocarcinomas and gallbladder cancer. Biliary tract cancers are diseases with unfavorable prognoses. In recent years, several lesions have been described as precursors that precede biliary cancers. They include flat and microscopic lesions known as biliary intraepithelial neoplasia, macroscopic and tumor-forming intraductal papillary biliary neoplasia, intraductal tubular neoplasia, and mucinous cystic neoplasm of the bile duct. These conditions are rarely diagnosed, while their natural history and progression to cancer have yet to be adequately characterized. This review examines the epidemiology, pathology, molecular biology, diagnosis, and therapy of these various precursors. Further research is required if we are to better understand this evolving field and improve the prevention and early detection of bile duct cancer.

A rare case of symptomatic grossly-visible biliary intraepithelial neoplasia mimicking cholangiocarcinoma

Background

Biliary intraepithelial neoplasia (BilIN) is often distinguished by what it is not: the precancerous lesions are not mass-forming, are not the cause of bile duct obstruction, and are small enough (less than 5 mm long) to evade detection by the naked eye. Here, we describe an atypical case of BilIN resembling cholangiocarcinoma (CC) that was large enough to be identified by diagnostic imaging and presented with obstructive jaundice caused by a hematoma in the common bile duct (CBD).

Case presentation

A 64-year-old man presented to our hospital with upper abdominal pain and anorexia. Initial laboratory examinations revealed increased total bilirubin and a computed tomography (CT) scan revealed a dilated CBD. Gastroenterologists performed an endoscopic sphincterotomy (EST), which revealed that the cause of obstructive jaundice was a hematoma in the CBD. Enhanced CT scan and magnetic resonance cholangiopancreatography (MRCP) performed after the hematoma was drained showed improved dilation of the CBD and an enhanced wall thickness of bile duct measuring 25 × 10 mm at the union of the cystic and common hepatic ducts. A cholangioscope detected an elevated tumor covered by sludge in the CBD, and we performed an extrahepatic bile duct resection and cholecystectomy. The postoperative course was uneventful and the pathological examination of the resected tumor revealed that although the ulcerated lesion had inflammatory granulation tissue, it did not contain the components of invasive carcinoma. Many consecutive intraepithelial micropapillary lesions spread around the ulcerated lesion, and the epithelial cells showed an increased nucleus-to-cytoplasm ratio, nuclear hyperchromasia, and architectural atypia. The pathological diagnosis was BilIN-1 to -2. Immunohistochemical staining showed that S100P was slightly expressed and MUC5AC was positive, while MUC1 was negative and p53 was not overexpressed.

Conclusion

We experienced an atypical case of BilIN mimicking CC that presented with obstructive jaundice caused by a hematoma in the CBD. Our case suggested that the occurrence of BilIN can be triggered by factors other than inflammation, and can grow to a size large enough to be detected by image analyses.

A case of small in situ perihilar cholangiocarcinoma incidentally accompanied by benign bile duct stricture after open cholecystectomy

Background

In situ cholangiocarcinoma is difficult to detect by imaging studies. Thus, cholangiocarcinoma is rarely resected with a preoperative definitive diagnosis, especially nonpapillary flat type in situ carcinoma, which is extremely rare.

Case presentation

A 70-year old man was diagnosed with gallbladder cancer and received open cholecystectomy with lymphadenectomy at a local hospital. Histologically, the tumor was localized in the mucosal layer, and no lymph node metastases were found. Three months later, hilar bile duct stricture due to delayed bile duct ischemia was found. Then, biliary drainage was performed with endoscopic biliary stenting. Three months later, the patient experienced cholangitis with septic shock, and percutaneous transhepatic biliary drainage (PTBD) into the left intrahepatic bile duct was performed. Unexpectedly, the aspiration bile cytology of the PTBD catheter showed malignant cells, and the patient was referred to our clinic for possible surgical treatment. According to additional studies, the hilar bile duct stricture was 3 cm in length. None of the imaging studies detected malignant cells in the bile duct around the hilar stricture. The left portal vein was obstructed due to inadvertent puncture of the PTBD. No findings indicated cholangiocarcinoma. We performed left hepatectomy with caudate lobectomy and extrahepatic bile duct resection. The postoperative course was uneventful. In the final pathology, flat type in situ carcinoma was found at the confluence of the right and left hepatic ducts, which was distant from the biliary stricture.

Conclusions

When a tumor is undetectable but cytology is positive, in situ cholangiocarcinoma may exist; thus, surgery should be carefully considered.

Common features between neoplastic and preneoplastic lesions of the biliary tract and the pancreas

the bile duct system and pancreas show many similarities due to their anatomical proximity and common embryological origin. Consequently, preneoplastic and neoplastic lesions of the bile duct and pancreas share analogies in terms of molecular, histological and pathophysiological features. Intraepithelial neoplasms are reported in biliary tract, as biliary intraepithelial neoplasm (BilIN), and in pancreas, as pancreatic intraepithelial neoplasm (PanIN). Both can evolve to invasive carcinomas, respectively cholangiocarcinoma (CCA) and pancreatic ductal adenocarcinoma (PDAC). Intraductal papillary neoplasms arise in biliary tract and pancreas. Intraductal papillary neoplasm of the biliary tract (IPNB) share common histologic and phenotypic features such as pancreatobiliary, gastric, intestinal and oncocytic types, and biological behavior with the pancreatic counterpart, the intraductal papillary mucinous neoplasm of the pancreas (IPMN). All these neoplastic lesions exhibit similar immunohistochemical phenotypes, suggesting a common carcinogenic process. Indeed, CCA and PDAC display similar clinic-pathological features as growth pattern, poor response to conventional chemotherapy and radiotherapy and, as a consequence, an unfavorable prognosis. The objective of this review is to discuss similarities and differences between the neoplastic lesions of the pancreas and biliary tract with potential implications on a common origin from similar stem/progenitor cells.

Anatomical, histomorphological and molecular classification of cholangiocarcinoma

Cholangiocarcinoma constitutes a heterogeneous group of malignancies that can emerge at any point of the biliary tree. Cholangiocarcinoma is classified into intrahepatic, perihilar and distal based on its anatomical location. Histologically, conventional perihilar/distal cholangiocarcinomas are mucin-producing adenocarcinomas or papillary tumours; intrahepatic cholangiocarcinomas are more heterogeneous and can be sub-classified according to the level or size of the displayed bile duct. Cholangiocarcinoma develops through multistep carcinogenesis and is preceded by dysplastic and in situ lesions. Definition and clinical significance of precursor lesions, including biliary intraepithelial neoplasia, intraductal papillary neoplasms of the bile duct, intraductal tubulopapillary neoplasms and mucinous cystic neoplasm, are discussed in this review. A main challenge in diagnosing cholangiocarcinoma is the fact that tumour tissue for histological examination is difficult to obtain. Thus, a major clinical obstacle is the establishment of the correct diagnosis at a tumour stage that is amenable to surgery which still represents the only curable therapeutic option. Current standards, methodology and criteria for diagnosis are discussed. Cholangiocarcinoma represents a heterogeneous tumour with regard to molecular alterations. In intrahepatic subtype, mainly two distinctive morpho-molecular groups can currently be discriminated. Large-duct type intrahepatic cholangiocarcinoma shows a high mutation frequency of oncogenes and tumour suppressor genes, such as KRAS and TP53 while Isocitrate Dehydrogenase 1/2 mutations and Fibroblast Growth Factor Receptor 2-fusions are typically seen in small-duct type tumours. It is most important to ensure the separation of the given anatomical subtypes and to search for distinct subgroups within the subtypes on a molecular and morphological basis.

Update on the pathology of liver neoplasms

Many advances have developed in the pathology of liver tumors in the recent decade. Examples of these advances include the use of glutamine synthetase in the diagnosis of focal nodular hyperplasia, subtyping of hepatocellular adenomas using molecular and immunohistochemical methods, the unraveling of the fusion transcript between the DNAJB1 gene and the PRKACA gene in fibrolamellar carcinoma, and the more unified classification and terminology in intrahepatic bile duct tumors and their precursor lesions. Nevertheless, challenges still remain, e.g., the differential diagnosis between well-differentiated hepatocellular carcinoma and hepatocellular adenoma; distinction among poorly differentiated hepatocellular carcinoma, cholangiocarcinoma and metastatic neoplasm; terminology of the combined hepatocellular carcinoma-cholangiocarcinoma, etc. This review aims to address updates in the pathologic diagnosis and clinical relevance of tumors of the liver and intrahepatic bile ducts in adults and their differential diagnosis and diagnostic pitfalls.

Pathology of intrahepatic cholangiocarcinoma

Intrahepatic cholangiocarcinoma (iCC) is a primary carcinoma of the liver with increasing significance and major pathogenic, clinical and therapeutic challenges. Classically, it arises from malignant transformation of cholangiocytes bordering small portal bile duct (BD) to second-order segmental large BDs. It has three major macroscopic growth pattern [mass-forming (MF), periductal infiltrative (PI), and intraductal growth (IG)] and histologically is a desmoplastic stroma-rich adenocarcinoma with cholangiocyte differentiation. Recent data pointed out noteworthy degree of heterogeneity in regards of their epidemiology and risk factors, pathological and molecular features, pathogenesis, clinical behaviors and treatment. Notably, several histological variants are described and can coexist within the same tumor. Several different cells of origin have also been depicted in a fraction of iCCs, amongst which malignant transformation of ductules, of hepatic stem/progenitor cells, of periductal glands or through oncogenic reprogramming of adult hepatocytes. A degree of pathological overlap with hepatocellular carcinoma (HCC) may be observed in a portion of iCC. A series of precursor lesions are today characterized and emphasize the existence of a multistep carcinogenesis process. Overall, these new data have brought up in proposal of new histological or molecular classifications, which could soon replace current anatomic-based classification and could have major impact on establishment of prognosis and on development of novel target treatment approaches.

Biliary Intraepithelial Neoplasia (BilIN) in Primary Sclerosing Cholangitis: The First Report from Iran

BACKGROUND

Primary sclerosing cholangitis (PSC) as one of the most common chronic cholestatic liver diseases is a main predisposing factor for the development of cholangiocarcinoma (CCA). Biliary intraepithelial neoplasia (BilIN) is defined as precancerous bile duct epithelial changes, which can be eventually led to cholangiocarcinoma. There are very few studies about the frequency of BilIN in the patients with PSC and its correlation with paraclinical findings.

OBJECTIVES

In this study, we tried to find the frequency of BilIN in the patients with PSC and correlate its presence with clinicopathologic factors.

METHODS

During two years (2014 - 15) of investigation, 80 explanted livers with the confirmed diagnosis of PSC were studied through precise inspection and thorough sectioning of the explanted livers. These findings were correlated with paraclinical findings to identify any predictor of these neoplastic epithelial changes.

RESULTS

During the study period of 2 years, among 80 livers with confirmed diagnosis of PSC, there were 43 cases with different types of metaplasia. The frequency of epithelial changes was as below: 29 (35%) for pyloric metaplasia, 9 (10.8%) for mucinous metaplasia, 3 (3.6%) for intestinal metaplasia, 1 (1.2%) for osteoid metaplasia, and 1 (1.2%) for squamous metaplasia. There was no epithelial dysplasia in the study sample; however, according to the most recent reports, mucinous metaplasia is considered as BilIN 1; therefore, there would be 9 cases of BilIN I. There has been no statistically significant difference between PSC cases and those with BilIN in demographic variables, except for bilirubin and CA19-9 which were higher in the PSC cases with BilIN.

CONCLUSIONS

This study showed that the frequency of BilIN was low among Iranian patients with PSC. High bilirubin and CA19-9 can be predictors of the development of bile duct epithelial changes in patients with PSC.

Updates on Precancerous Lesions of the Biliary Tract: Biliary Precancerous Lesion

Precursor lesions of invasive adenocarcinoma of the bile duct (cholangiocarcinoma) have been increasingly recognized during the past decade because of the results of multiple studies on the carcinogenesis of cholangiocarcinoma, technologic advancements in diagnostic imaging modalities, and an increase in the volume of elective procedures. The two main precursor lesions of cholangiocarcinoma that have evolved are biliary intraepithelial neoplasia and intraductal papillary neoplasm of the bile duct. These lesions demonstrate histomorphologic similarities to pancreatic intraepithelial neoplasia and intraductal papillary mucinous neoplasm of the pancreas, respectively, whereas mechanisms of carcinogenesis and risk of progressive disease appear distinct. An enhanced understanding of the clinical presentation and pathologic features of precursor lesions of the biliary tract and use of the correct terminology will facilitate efficient communication between surgeons, oncologists, and pathologists and improve quality of patient care.

Latest advances in the pathological understanding of cholangiocarcinomas

Cholangiocarcinomas (CCAs) are anatomically classified into intrahepatic, perihilar, and distal types. The gross pathological classification of intrahepatic CCAs divides them into mass-forming, periductal-infiltrating, and intraductal-growth types; and perihilar/distal CCAs into flat- and nodular-infiltrating and papillary types. Unique preinvasive lesions appear to precede individual gross types of CCA. Biliary intraepithelial neoplasia, a flat lesion, precedes periductal-, flat-, and nodular-infiltrating CCAs, whereas intraductal papillary neoplasm of the bile duct (IPNB) precedes the intraductal-growth and papillary type of CCAs. IPNBs are heterogeneous in their histological and pathological profiles along the biliary tree. Hepatobiliary cystadenomas/adenocarcinomas are reclassified as cystic IPNBs and hepatic mucinous cystic neoplasms. Peribiliary glands may participate in the development of CCAs. These latest findings present a new challenge for understanding the pathology of CCAs.

Comparison of clinicopathological characteristics between patients with occupational and non-occupational intrahepatic cholangiocarcinoma

BACKGROUND

An outbreak of cholangiocarcinoma has been reported among workers of an offset color proof-printing department at a printing company in Japan. In this study, we compared the clinicopathological findings of this type of intrahepatic cholangiocarcinoma (occupational ICC) and non-occupational ICC.

METHODS

The clinical records of 51 patients with perihilar-type ICC who underwent liver resection, including five patients with occupational ICC were retrospectively reviewed. The clinicopathological features were compared.

RESULTS

In the occupational group, the patients were significantly younger (P < 0.01), while serum γ-glutamyl transpeptidase activity and the proportions of patients with regional dilatation of the bile ducts without tumor-induced obstruction were significantly higher (P = 0.041 and P < 0.01, respectively); the indocyanine green retention rate at 15 min was significantly lower (P = 0.020). On pathological examinations, precancerous or early cancerous lesions, such as biliary intraepithelial neoplasia and intraductal papillary neoplasm of the bile duct, were observed at various sites of the bile ducts in all occupational ICC patients; such lesions were observed in only six patients in the control group (P < 0.01).

CONCLUSIONS

The clinicopathological findings including age, liver function test results, diagnostic imaging findings, and pathological findings differed between the occupational and control groups.

Tumoral Versus Flat Intraepithelial Neoplasia of Pancreatobiliary Tract, Gallbladder, and Ampulla of Vater

Context.—The identification of a precursor lesion is important to understanding the histopathologic and genetic alterations in carcinogenesis. There are a plethora of terminologies that describe precursor lesions of the pancreatobiliary tract, ampulla of Vater, and gallbladder. The current terminologies for precursor lesions may make it difficult to understand the tumor biology. Here, we propose the concept of tumoral and flat intraepithelial neoplasia to improve our understanding of precursor lesions of many epithelial organs, including the pancreatobiliary tract, ampulla of Vater, and gallbladder.

Objective.—To understand the dichotomous pattern of tumoral and flat intraepithelial neoplasia in carcinogenesis of pancreatobiliary tract, ampulla of Vater, and gallbladder.

Data Sources.—Review of relevant literatures indexed in PubMed.

Conclusions.—Tumoral intraepithelial neoplasia presents as an intraluminal or intraductal, mass-forming, polypoid lesion or a macroscopic, visible, cystic lesion without intracystic papillae. Microscopically, tumoral intraepithelial neoplasia shows various proportions of papillary and tubular architecture, often with a mixed pattern, such as papillary, tubular, and papillary-tubular. The malignant potential depends on the degree of dysplasia and the cell phenotype of the epithelium. Flat intraepithelial neoplasia presents as a flat or superficial, spreading, mucosal lesion that is frequently accompanied by an invasive carcinoma. Tumoral and flat intraepithelial neoplasias are not homogeneous entities and may exhibit histopathologic spectrum changes and different genetic profiles. Although intraepithelial neoplasia showed a dichotomous pattern in the tumoral versus flat types, they can coexist. Tumoral and flat intraepithelial neoplasia can be interpreted as part of a spectrum of changes in the carcinogenesis pathway of each organ.

Successful treatment of biliary intraepithelial neoplasia in the common bile duct via local excision: A case report

Biliary intraepithelial neoplasia (BilIN), a precursor lesion of bile duct adenocarcinomas, rarely occurs in the extrahepatic bile duct, and therefore uniform treatment guidelines are lacking. The present study reports a case of BilIN in the common bile duct (CBD) in a 77-year-old man, who presented with upper abdominal malaise without jaundice. Imaging modalities revealed a CBD luminal tumor and dilated intrahepatic and extrahepatic bile ducts. To the best of our knowledge, local excision of the lesion was performed for the first time for this type of tumor in the present study. Pathological examination gave a definite diagnosis of high-grade BilIN in the CBD. No evidence of recurrence was observed during a 3-year follow-up period. This case report suggests that local excision is able to successfully treat BilIN in the CBD.

Cholangiocarcinoma with intraductal tubular growth pattern versus intraductal papillary growth pattern

Intraductal neoplasms of the bile duct are macroscopically characterized by exophytic or polypoid growth patterns and have a favorable prognosis. Although some tumors with a predominantly tubular microscopic pattern have been reported, they have not been well characterized clinicopathologically. The purpose of the present study was to compare the newly recognized cholangiocarcinoma with an intraductal tubular growth pattern and cholangiocarcinoma with an intraductal papillary growth pattern and to investigate the pathological and prognostic significance of the former. This study analyzed 161 patients with tumors with exophytic or polypoid growth patterns from a large series of 733 cholangiocarcinoma cases surgically resected from January 1998 to May 2013. The study patients were divided into two groups: those whose tumors showed a predominantly tubular growth pattern (n=52) and those whose tumors exhibited a predominantly papillary growth pattern (n=109). Tubular growth pattern was associated with combined vascular resection and the absence of macroscopic mucin. Several histological indexes were significantly higher for the tubular growth pattern than the papillary one, including tubular adenocarcinoma, depth of invasion, microscopic lymphatic invasion, venous invasion, perineural invasion, and necrosis. Although the survival curves overlapped (P=0.693), the rate of liver metastasis was significantly higher for the tubular growth pattern than for the papillary one (P=0.012). Genomic DNA analysis focusing on somatic mutations in codons 12 and 13 of KRAS and codon 600 of BRAF revealed only one (4%) KRAS and no BRAF mutation among the 25 tubular cases examined. In conclusion, the tubular growth pattern exhibited differences in some histologic indexes, in addition to a higher hepatic metastasis rate and a lower KRAS mutation frequency, compared with the papillary growth pattern, but no difference in prognosis was observed. The distinctiveness of this tubular neoplasm should be further examined in the future.

Distal bile duct carcinomas and pancreatic ductal adenocarcinomas: postulating a common tumor entity

The set definition of distal cholangiocarcinomas and adenocarcinomas of the pancreatic head is challenged by their close anatomical relation, similar growth pattern, and corresponding therapeutic outcome. They show a mutual development during embryologic organ formation and share phenotypic characteristics. This review will highlight the similarities with regard to the common origin of their primary organs, histopathological similarities, and modern clinical management. Thus, we propose to subsume those entities under a common superfamily.

Clinical and biological significance of precursor lesions of intrahepatic cholangiocarcinoma

Cholangiocarcinoma (CC) is primarily a malignant tumor of older adults most prevalent in Southeast Asia, where liver fluke infestation is high. However the etiology in western countries is unknown. Although the incidence of extrahepatic cholangiocarcinoma has remained constant, incidence of intrahepatic CC (ICC) which differs in morphology, pathogenesis, risk factors, treatment and prognosis is increasing. While this increase is associated with hepatitis C virus infection, chronic nonalcoholic liver disease, obesity, and smoking, the pathogenesis of ICC and molecular alterations underlying the carcinogenesis are not completely elucidated. Benign biliary lesions such as biliary intraepithelial neoplasia, intraductal papillary neoplasm of the bile duct, von Meyenburg complex or bile duct hamartoma, and bile duct adenoma have been associated with ICC. For each of these entities, evidence suggests or supports a role as premalignant lesions. This article summarized the important biological significance of the precursor lesions of ICC and the molecular mechanisms that may be involved in intrahepatic cholangiocarcinogenesis.

Clinical and pathological features of intraductal papillary neoplasm of the biliary tract and gallbladder

BACKGROUND

Intraductal papillary neoplasms of the biliary tract (IPNB) and intracholecystic papillary neoplasms (ICPN) are rare tumours characterized by intraluminal papillary growth that can be associated with invasive carcinoma. Their natural history remains poorly understood. This study examines clinicopathological features and outcomes.

METHODS

Patients who underwent surgery for IPNB/ICPN (2008-2014) were identified. Descriptive statistics and survival data were generated.

RESULTS

Of 23 patients with IPNB/ICPN, 10 were male, and the mean age was 68 years. The most common presentations were abdominal pain (n = 10) and jaundice (n = 9). Tumour locations were: intrahepatic (n = 5), hilar (n = 3), the extrahepatic bile duct (n = 8) and the gallbladder (n = 7). Invasive cancer was found in 20/23 patients. Epithelial subtypes included pancreatobiliary (n = 15), intestinal (n = 7) and gastric (n = 1). The median follow-up was 30 months. The 5-year overall (OS) and disease-free survivals (DFS) were 51% and 57%, respectively. Decreased OS (P = 0.09) and DFS (P = 0.05) were seen in patients with tumours expressing MUC1 on immunohistochemistry (IHC).

CONCLUSION

IPNB/ICPN are rare precursor lesions that can affect the entire biliary epithelium. At pathology, the majority of patients have invasive carcinoma, thus warranting a radical resection. Patients with tumours expressing MUC1 appear to have worse OS and DFSs.

Pathologic classification of cholangiocarcinoma: New concepts

Herein, we propose a new pathologic classification of cholangiocarcinoma (CCA) based on recent progress in studies of preinvasive CCA lesions and the relationship of CCA to hepatic progenitor cells, as well as a new concept with respect to the pathologic similarities between biliary and pancreatic neoplasms. Depending on anatomical location, CCA is classifiable as intrahepatic (iCCA), perihilar (pCCA), and distal CCA (dCCA). iCCA is classifiable as the conventional type and the bile ductular type, whereas pCCA and dCCA mainly present as conventional adenocarcinoma. In addition, these three CCAs may present as the intraductal neoplasm type or rare variants. Bile ductular CCA resembles proliferating bile ductules and expressing hepatic progenitor cell phenotypes. Four types of preinvasive lesions are proposed: flat, papillary, tubular lesion, and cystic lesion. These lesions are eventually followed by invasive CCA. Interestingly, these preinvasive lesions have pancreatic counterparts. This CCA classification may introduce a new field of CCA research.

An immunohistochemical marker panel including claudin-18, maspin, and p53 improves diagnostic accuracy of bile duct neoplasms in surgical and presurgical biopsy specimens

Biliary tract cancers have an extremely poor outcome, and specific diagnostic markers and effective treatments are needed urgently. In this study, we assessed the capacity of panel of immunohistochemical markers including claudin-18, maspin, and p53 to distinguish biliary tract carcinoma and biliary intraepithelial neoplasia (BilIN) from non-neoplastic epithelium. We performed a retrospective study of 66 biliary tract cancer specimens and 63 specimens with non-neoplastic lesions. Of the surgical specimens, 96.7 % with adenocarcinoma/BilIN were detected as neoplastic, and all 63 specimens histologically diagnosed as non-neoplastic lesion were detected as non-neoplastic with high sensitivity (91.1 %) and specificity (100 %). Of presurgical endobiliary forceps biopsy specimens, all with adenocarcinoma/BilIN and only 1 of the 19 with a non-neoplastic lesion were distinguished as neoplastic with high sensitivity (100 %) and specificity (94.7 %). Moreover, this panel provided good separation of neoplasm from malignancy-undetermined atypical epithelium (18/21, 85.7 %). This panel achieves a more reliable distinction of biliary tract cancers and BilINs from non-neoplastic epithelia in both surgical and biopsy specimens than immunohistochemical analysis with single antibodies and is useful in supporting a diagnosis of adenocarcinoma and BilIN.

The outcome of ipsilateral hemihepatectomy in mucin-producing bile duct tumors

Background

Mucin-producing bile duct tumors (MPBTs) are unusual, and we present our experience with nine surgically proven cases.

Methods

Between November 2002 and November 2012, 9 patients with surgically proven MPBTs (including history of relevant hepatobiliary surgery in 6 patients) were encountered. Their clinical, imaging, and surgical findings were reviewed.

Results

The most common symptom is intermittent jaundice, which occurs in seven patients. The diagnostic specificity was 77.8% by preoperative Magnetic Resonance Cholangiopancreatography (MRCP). All the patients underwent ipsilateral hemihepatectomy or remnant hemihepatectomy, accompanied caudate lobectomy in one case and concomitant Roux-en-Y choledochojejunostomy in four cases. Postoperative course was uneventful. One patient, who had intra-abdominal recurrence 59 months after surgery, was received reoperation without recurrence at the last follow-up. The remaining eight patients were alive without disease recurrence.

Conclusion

Based on our follow up of 9 cases that were surgically treated for MPBTs, we conclude that ipsilateral hemihepatectomy is a safe surgical procedure with an observed recurrence risk of 11.1% and all long-term survival.

Pathological diagnosis of flat epithelial lesions of the biliary tract with emphasis on biliary intraepithelial neoplasia

Flat epithelial lesions of the biliary tract cannot be detected by the image analysis, and the diagnosis entirely depends on pathological examination. The biliary tract is often affected by inflammatory conditions, and the resultant changes of the biliary epithelium make it difficult to differentiate them from neoplasia. Thus, the pathological diagnosis of biliary flat epithelial lesions can be challenging. In the biliary tract, there are several forms of intraepithelial neoplasia of the flat type, and biliary intraepithelial neoplasia (BilIN) is known as one of such lesions that represent the multistep cholangiocarcinogenesis. In this article, the diagnostic criteria and the differential diagnosis of biliary flat epithelial lesions, particularly focusing on BilIN, were presented and discussed to provide help to advance clinical and research applications of the BilIN system.

Clinicopathological significance of S100 protein expression in cholangiocarcinoma

BACKGROUND AND AIM

Cholangiocarcinoma arising in the large bile ducts undergoes a multistep carcinogenesis process in chronic biliary diseases, and biliary intraepithelial neoplasia is known as a precursor lesion. This study examined the expression of S100 proteins in the multistep cholangiocarcinogenesis to clarify their clinicopathological significance.

METHODS

Immunohistochemical analysis was performed for the expression of S100A2, S100A4, S100A6, and S100P. Bile concentrations of S100P were measured using enzyme-linked immunosorbent assay.

RESULTS

The immunohistochemical expression of the S100 proteins was increased in biliary intraepithelial neoplasia as well as invasive adenocarcinoma of perihilar cholangiocarcinoma. Among the proteins, S100P expression was most drastically increased during the multistep carcinogenesis process. In cases with perihilar and extrahepatic cholangiocarcinoma, the immunohistochemical expression of S100A2 in cholangiocarcinoma cells significantly correlated with the histological grade, lymph node metastasis, clinical stage, and a poor survival rate of the patients. The bile levels of S100P were increased significantly in patients with cholangiocarcinoma compared with those in patients with lithiasis. Receiver operating characteristic curve analysis showed that S100P bile concentration was an indicator of cholangiocarcinoma with a sensitivity of 93% and a specificity of 70%.

CONCLUSIONS

These results suggest that S100P may be useful for the detection of cholangiocarcinoma as tissue and bile biomarkers, and the immunohistochemical expression of S100A2 is a potential prognostic marker in cholangiocarcinoma patients.

Pathological aspects of so called "hilar cholangiocarcinoma"

Cholangiocarcinoma (CC) arising from the large intrahepatic bile ducts and extrahepatic hilar bile ducts share clinicopathological features and have been called hilar and perihilar CC as a group. However, “hilar and perihilar CC” are also used to refer exclusively to the intrahepatic hilar type CC or, more commonly, the extrahepatic hilar CC. Grossly, a major distinction can be made between papillary and non-papillary tumors. Histologically, most hilar CCs are well to moderately differentiated conventional type (biliary) carcinomas. Immunohistochemically, CK7, CK20, CEA and MUC1 are normally expressed, being MUC2 positive in less than 50% of cases. Two main premalignant lesions are known: biliary intraepithelial neoplasia (BilIN) and intraductal papillary neoplasm of the biliary tract (IPNB). IPNB includes the lesions previously named biliary papillomatosis and papillary carcinoma. A series of 29 resected hilar CC from our archives is reviewed. Most (82.8%) were conventional type adenocarcinomas, mostly well to moderately differentiated, although with a broad morphological spectrum; three cases exhibited a poorly differentiated cell component resembling signet ring cells. IPNB was observed in 5 (17.2%), four of them with an associated invasive carcinoma. A clear cell type carcinoma, an adenosquamous carcinoma and two gastric foveolar type carcinomas were observed.

Precancerous lesions of the biliary tree

The neoplasms of the biliary tree include the carcinomas of the intra- and extrahepatic bile ducts, the gallbladder and the ampulla. Two types of precancerous lesions precede these adenocarcinomas: the flat and non-tumour forming type that is called biliary intraepithelial neoplasia, and the papillary and tumour-forming type that has been named intraductal papillary neoplasm of the bile duct. Rarely also biliary mucinous cystic neoplasm can give rise to invasive biliary adenocarcinomas. This review discusses the pathological, molecular, epidemiological, clinical and prognostic features of the precancerous biliary lesions, separated according to their origin in the bile ducts, the ampulla and the gall bladder.

Histological characteristics of biliary intraepithelial neoplasia-3 and intraepithelial spread of cholangiocarcinoma

The increasing grades of biliary intraepithelial neoplasia (BilIN) reflect multistep carcinogenesis of cholangiocarcinoma, BilIN-3 representing the carcinoma in situ stage. A different form of in situ growth form of cancer cells is the intraepithelial spreading of cholangiocarcinoma cells. We examined the histological characteristics of carcinoma in situ in the biliary tract on 64 partial hepatectomy specimens with a diagnosis of hepatolithiasis. We distinguished two forms of carcinoma in situ: BilIN-3 and intraepithelial spread of carcinoma (IES). BilIN-3 is defined by epithelial atypia gradually decreasing towards the transition to adjacent normal biliary epithelium. In IES, the lesion shows an abrupt transition to normal biliary epithelium, in which the intraepithelial carcinoma then tends to spread. BilIN-3 and IES were observed in 17 (94 %) and seven (39 %), respectively, in cases of invasive cholangiocarcinoma (n = 18), and neither of them was observed in cases without invasive cholangiocarcinoma (n = 46). Most lesions of BilIN-3 and IES microscopically showed a flat or pseudopapillary pattern. The less frequent micropapillary configuration was noted more often in BilIN-3. BilIN-3 was not observed in septal and small intrahepatic bile ducts, while IES was regularly observed in such bile ducts. Immunohistochemical analysis showed p53 to be expressed significantly more frequently in IES (29 %) than in BilIN-3 (8 %). In conclusion, carcinoma in situ in the biliary tract is morphologically heterogeneous, and it is important to distinguish BilIN-3 and intraepithelial carcinoma spreading as distinct lesions, to better understand their biology.

S100P immunostaining identifies a subset of peripheral-type intrahepatic cholangiocarcinomas with morphological and molecular features similar to those of perihilar and extrahepatic cholangiocarcinomas

AIMS

S100P is a calcium-binding protein that is frequently expressed in pancreatic adenocarcinoma and perihilar cholangiocarcinoma. The aim of this study was to investigate the pathological significance of the expression of S100P in peripheral intrahepatic cholangiocarcinoma (ICC).

METHODS AND RESULTS

Immunohistochemical staining was used to investigate S100P expression in 112 cases of peripheral ICC. The results were compared with those for perihilar and extrahepatic cholangiocarcinomas. Patients with S100P-positive peripheral ICC were more likely to have elevated serum levels of carcinoembryonic antigen (CEA) and CA19-9 than those with S100P-negative peripheral ICCs. All cases of peripheral ICC associated with intrahepatic lithiasis and all cases with intraductal/periductal growth patterns were positive for S100P. S100P-positive peripheral ICCs were highly associated with 'bile duct' morphology rather than cholangiolar differentiation. Nearly all cases of perihilar and extrahepatic cholangiocarcinoma were positive for S100P. Similarly to perihilar and extrahepatic cholangiocarcinomas, S100P-positive peripheral ICCs showed more frequent expression of CEA and MUC2, and were more likely to be N-cadherin-negative, than S100P-negative cases. Notably, K-RAS mutations were only detected in S100P-positive peripheral ICCs, with a frequency similar to that in perihilar and extrahepatic cholangiocarcinomas. Patients with S100P-positive peripheral ICC were more likely to have poor prognoses than those with S100P-negative tumours.

CONCLUSIONS

S100P immunostaining identifies a subset of peripheral ICC that probably originates from larger bile ducts. This subset of peripheral ICCs shares common morphological and molecular features with perihilar and extrahepatic cholangiocarcinomas.

Preneoplastic conditions underlying bile duct cancer

BACKGROUND

Malignancies arising from the biliary tract can arise from the epithelial lining of the biliary tract and surrounding tissues. Conditions that predispose to malignancy as well as preneoplastic changes in biliary tract epithelia have been identified. In this overview, we discuss preneoplastic conditions of the biliary tract and emphasize their clinical relevance.

RESULTS

Chronic biliary tract inflammation predisposes to cancer in the biliary tract. Biliary tract carcinogenesis involves a multistep process as a consequence of chronic biliary epithelial injury or inflammation. Reminiscent of other gastrointestinal epithelial malignancies such as gastric, colon, and pancreatic cancer, biliary tract cancers may evolve via multistep progression from epithelial hyperplasia and dysplasia to malignant transformation. The potential role of initiating cells is also becoming recognized.

CONCLUSIONS

In spite of improved risk factor recognition, and advances in diagnostic tools, the early diagnosis of pre-malignant or malignant biliary tract conditions is extremely challenging, and there is a paucity of evidence on which to base their management. As a result, the role of pre-emptive surgery remains largely undefined.

Distinctive expression of CD133 between intraductal papillary neoplasms of the bile duct and bile duct adenocarcinomas

AIM

  Intraductal papillary neoplasm of the bile duct (IPNB), a novel entity of biliary disease, is recently advocated as the counterpart of pancreatic intraductal papillary mucinous neoplasm (IPMN) because both are in common with a large amount of mucin production and papillary growth. Based on our recent finding that expression of CD133, a cancer stem cell marker, is lacking in pancreatic IPMN, we herein focused on CD133 expression of IPNB in comparison with intrahepatic cholangiocellular carcinoma (IHCCC) or hilar bile duct cancer (HBDC).

METHODS

  Expression of CD133 protein was immunohistochemically determined in patients with IPNB (n = 7), IHCCC (n = 16) or HBDC (n = 8). In addition, morphological and immunohistochemical mucin expression patterns were characterized in IPNB, and clinicopathological features including prognosis were compared between IPNB and other biliary tumors.

RESULTS

  The IPNB group included significantly more females than the other two groups, and had a longer survival time. While no CD133 expression was observed in IPNB tumor, 16.4% of cancer cells in IHCCC and 17.2% of cells in HBDC expressed CD133. Among seven patients with IPNB, six (86%) were morphologically the pancreatobiliary type and four of six showed mucin expression pattern of the typical pancreatobiliary type (MUC1+/MUC2-/MUC5AC+).

CONCLUSION

  Loss of CD133 expression supports the hypothesis that IPNB is a counterpart of pancreatic IPMN with a differing carcinogenesis from conventional bile duct adenocarcinomas.