Biliary papillary tumors share pathological features with intraductal papillary mucinous neoplasm of the pancreas

Intraductal Implantation of Biliary Neoplasms: A Potential Cause of "Multifocal" Tumors

Multiple biliary tumors rarely develop in patients without underlying chronic hepatobiliary disease. Those lesions are regarded as multifocal neoplasms if there is no interconnecting dysplasia. This study aimed to determine whether 2 separate tumors in the biliary tract represent true multifocal independent tumorigenesis or intraluminal implantation of a single neoplasm. Two separate biliary tumors without intervening dysplasia were identified in 9 cases: biliary intraductal papillary neoplasm (IPNB; n=5) and extrahepatic cholangiocarcinoma (n=4). The 2 tumors were histologically similar in all cases. In 5 metachronous cases, the second tumor developed 2 to 13 years after the complete resection of the first tumor. In 4 synchronous cases, 2 separate neoplasms were identified in a surgical specimen. The metachronous presentation was more common in IPNB cases, whereas the synchronous development was more frequent in cholangiocarcinoma cases. The second tumors in 4 metachronous cases (4/5; 80%) and smaller lesions in all synchronous cases (4/4; 100%) were located in a lower part of the biliary. Immunophenotypes of cytokeratins and mucin core proteins were almost identical between the 2 lesions. Next-generation sequencing also confirmed that the 2 neoplasms shared gene mutations involving KRAS, GNAS, APC, BRAF, CTNNB1, SMAD4, TP53, or ARID1A in all cases. In conclusion, multiple biliary tumors without underlying chronic biliary disease are most likely due to intraductal implantation of a single neoplasm. Thick mucinous bile in IPNB and increasing use of trans-ampullary biliary interventions may contribute to this unique form of tumor extension.

A Review of Type 1 and Type 2 Intraductal Papillary Neoplasms of the Bile Duct

Intraductal papillary neoplasm of the bile duct (IPNB) is a heterogeneous disease similar to intraductal papillary mucinous neoplasm of the pancreas. These lesions have been recognized as one of the three major precancerous lesions in the biliary tract since 2010. In 2018, Japanese and Korean pathologists reached a consensus, classifying IPNBs into type l and type 2 IPNBs. IPNBs are more prevalent in male patients in East Asia and are closely related to diseases such as cholelithiasis and schistosomiasis. From a molecular genetic perspective, IPNBs exhibit early genetic variations, and different molecular pathways may be involved in the tumorigenesis of type 1 and type 2 IPNBs. The histological subtypes of IPNBs include gastric, intestinal, pancreaticobiliary, or oncocytic subtypes, but type 1 IPNBs typically exhibit more regular and well-organized histological features than type 2 IPNBs and are more commonly found in the intrahepatic bile ducts with abundant mucin. Due to the rarity of these lesions and the absence of specific clinical and laboratory features, imaging is crucial for the preoperative diagnosis of IPNB, with local bile duct dilation and growth along the bile ducts being the main imaging features. Surgical resection remains the optimal treatment for IPNBs, but negative bile duct margins and the removal of lymph nodes in the hepatic hilum significantly improve the postoperative survival rates for patients with IPNBs.

Oncocytic type has distinct immunohistochemical and recurrence-free survival than other histologic types of the intraductal papillary neoplasm of the bile duct

Although intraductal oncocytic papillary neoplasm (IOPN) was considered distinct from the intraductal papillary neoplasm of the pancreas, the oncocytic histologic type remained as a subtype of intraductal papillary neoplasms of the bile duct (IPNBs) with gastric, intestinal, and pancreatobiliary types based on the fifth edition of the WHO classification. To test the characteristics of the oncocytic type of IPNBs, the histopathologic, immunohistochemical (Hep Par-1 and CD117), and clinical characteristics of 13 oncocytic type were compared with 114 others (15 gastric, 39 pancreatobiliary, and 60 intestinal) IPNB types. The oncocytic type, which occupied about 9% of IPNBs, was more frequent in females (p < 0.05) and larger (mean, 5.3 vs. 3.6 cm; p < 0.002) than other IPNB types. Immunohistochemically, the oncocytic type had more frequent combined Hep Par-1 and CD117 expression than other IPNB types (all p < 0.05). The recurrence-free survival rate for patients with the oncocytic type (5-year survival, 100%) was significantly higher (p = 0.015) than for those with other histologic types (59.9%). The oncocytic type had distinct histopathologic, immunohistochemical, and survival outcomes from other IPNBs. Therefore, it can be separated from other IPNB types and classified as one independent entity, similar to IOPN of the pancreas.

Recent Advances in Pathology of Intrahepatic Cholangiocarcinoma

Intrahepatic cholangiocarcinoma (ICCA) is a malignant epithelial neoplasm characterized by biliary differentiation within the liver. ICCA is molecularly heterogeneous and exhibits a broad spectrum of histopathological features. It is a highly aggressive carcinoma with high mortality and poor survival rates. ICCAs are classified into two main subtypes: the small-duct type and large-duct types. These two tumor types have different cell origins and clinicopathological features. ICCAs are characterized by numerous molecular alterations, including mutations in KRAS, TP53, IDH1/2, ARID1A, BAP1, BRAF, SAMD4, and EGFR, and FGFR2 fusion. Two main molecular subtypes-inflammation and proliferation-have been proposed. Recent advances in high-throughput assays using next-generation sequencing have improved our understanding of ICCA pathogenesis and molecular genetics. The diagnosis of ICCA poses a significant challenge for pathologists because of its varied morphologies and phenotypes. Accurate diagnosis of ICCA is essential for effective patient management and prognostic determination. This article provides an updated overview of ICCA pathology, focusing particularly on molecular features, histological subtypes, and diagnostic approaches.

Papillary Neoplasms of the Gallbladder and Extrahepatic Bile Ducts: A Report of Two Cases With Associated Invasive Carcinoma

Intracholecystic papillary neoplasm (ICPN) of the gallbladder is a macroscopically visible premalignant lesion protruding into the gallbladder lumen, with infrequent association with invasive adenocarcinoma. Intraductal papillary neoplasm of the bile ducts (IPNB) is a non-invasive lesion characterized by intraductal papillary or villous architecture. Both ICPN and IPNB are rare findings in the gallbladder and biliary tract pathology. Diagnosis relies on clinical manifestations, imaging techniques, and comprehensive histological examination. Here, we present two cases: a 63-year-old male with mild abdominal pain found to have a gallbladder mass, diagnosed histologically as ICPN with associated invasive carcinoma; and a 65-year-old female with chronic jaundice and a large tumor mass in the common bile duct, histologically diagnosed as IPNB with associated invasive carcinoma. These cases highlight the importance of a careful and thorough microscopic examination to rule out differential diagnoses and to reveal any potential invasive carcinoma associated with these uncommon lesions.

Intraductal papillary neoplasm of the bile duct: A case report of a rare tumor with a brief review of literature

INTRODUCTION AND IMPORTANCE

Intraductal papillary neoplasm of the bile duct (IPNB) is a rare neoplasm, mostly found in patients from far Eastern areas where hepatolithiasis and clonorchiasis are endemic. Very few cases are reported from India.

CASE PRESENTATION

We present a case of recurrent cholangitis in a 59-year-old male, initially suspected to have IPNB based on preoperative imaging. Confirmation occurred intraoperatively, with mucin-filled bile ducts and papillary lesions in the resected hepatic duct. Treatment included left hepatectomy, extrahepatic bile duct excision, and Roux-en-Y hepaticojejunostomy. Histopathology indicated invasive pancreatobiliary-type IPNB with clear margins. The patient experienced post-hepatectomy hepatic insufficiency and superficial incisional surgical site wound infection, managed conservatively. Discharge occurred on postoperative day 21, with satisfactory recovery at the 16-month follow-up.

CLINICAL DISCUSSION

IPNB is recognized as the biliary equivalent of intraductal papillary mucinous neoplasm, as these two conditions exhibit multiple commonalities in terms of clinical and histopathological characteristics. The unique aspect of our case lies in the intricacies associated with its diagnosis. Initially, imaging modalities did not yield a definitive characterization of the lesion. Notably, the endoscopist misinterpreted mucin expression emanating from the papilla as purulent material, primarily due to the patient's concurrent cholangitis. Subsequent repetitions of both CT scan and MRI provided some valuable insights that contributed to the diagnostic clarity of the IPNB.

CONCLUSION

In cases of symptoms like biliary obstruction with bile duct dilation, wall nodules, papillary/solid-cystic masses, and upstream-downstream dilation, IPNB should be considered. Striving for R0 resection is crucial for enhanced long-term patient survival.

Intraductal papillary neoplasms of the bile ducts-what can be seen with ultrasound?

Intraductal papillary neoplasm of the bile ducts is a rare tumor. Characteristic features include bile duct dilatation, cystic lesions with communication to the bile ducts, and intraluminal solid nodules arising from the bile duct wall. As in pancreatic intraductal papillary mucinous neoplasia, intestinal, pancreaticobiliary, gastric, and oncocytic types are described. Intraductal papillary neoplasm of the bile ducts has a high potential for malignancy, and patients should be surgically resected when possible. In this review, the complex imaging diagnosis is presented. The main focus is on contrast-enhanced ultrasound, an established method for many other indications whose potential on the biliary system should be better exploited. In the present article, typical contrast-enhanced ultrasound findings in intraductal papillary neoplasm of the bile ducts are demonstrated.

Intraductal papillary neoplasm of the bile duct: review of updated clinicopathological and imaging characteristics

BACKGROUND

Intraductal papillary neoplasm of the bile duct (IPNB) is a relatively rare disease and is known as one of the premalignant lesions in the biliary tract. The concept of IPNB has changed through numerous studies and is still evolving. As a lesser studied clinical entity compared with its pancreatic counterpart, intraductal papillary mucinous neoplasm, IPNB has been described in many similar terms, including biliary papillomatosis, biliary intraductal papillary-mucinous neoplasm, and papillary cholangiocarcinoma. This is based on the diversity of histopathological spectrum of IPNB.

METHODS

This review investigated previous studies including original articles, case studies, and expert opinions. Recently, two types of IPNB (types 1 and 2) have been proposed and validated based on the content first established in the WHO 2010 criteria.

RESULTS

This review provides a comprehensive analysis of existing literature, summarizing the clinical, radiological, morphological, and pathological characteristics of IPNB.

CONCLUSION

Given the ongoing ambiguity and controversies surrounding IPNB, future research, including large population-based studies and molecular investigations, is essential to enhance understanding of this disease.

Intra-ampullary papillary-tubular neoplasm

Video 1Cholangioscopic examination of the ampullary channel and extrahepatic bile duct.

Epidemiology and outcome of individuals with intraductal papillary neoplasms of the bile duct

BACKGROUND

Intraductal papillary neoplasm of the bile duct (IPNB) is a rare distinct subtype of precursor lesions of biliary carcinoma. IPNB is considered to originate from luminal biliary epithelial cells, typically displays mucin-hypersecretion or a papillary growth pattern, and results in cystic dilatation[1]. IPNB develops anywhere in the intrahepatic and extrahepatic biliary tracts, and can occur in various pathological stages from low-grade dysplasia to invasive carcinoma. IPNBs have similar phenotypic changes in the occurrence and development of all subtypes, and the prognosis is significantly better than that of traditional (non-papillary) cholangiocarcinoma.

AIM

To evaluate the clinicopathological features of IPNB to provide evidence-based guidance for treatment.

METHODS

Invasive IPNB, invasive intraductal papillary mucinous neoplasm of the pancreas (IPMN), and traditional cholangiocarcinoma data for affected individuals from 1975 to 2016 were obtained from the Surveillance, Epidemiology, and End Results (SEER) database. Annual percentage changes (APCs) in the incidence and incidence-based (IB) mortality were calculated. We identified the independent predictors of overall survival (OS) and cancer-specific survival (CSS) in individuals with invasive IPNB.

RESULTS

The incidence and IB mortality of invasive IPNB showed sustained decreases, with an APC of -4.5% (95%CI: -5.1% to -3.8%) and -3.3% (95%CI: -4.1% to -2.6%) (P < 0.001), respectively. Similar decreases in incidence and IB mortality were seen for invasive IPMN but not for traditional cholangiocarcinoma. Both OS and CSS for invasive IPNB were better than for invasive IPMN and traditional cholangiocarcinoma. A total of 1635 individuals with invasive IPNB were included in our prognosis analysis. The most common tumor sites were the pancreaticobiliary ampulla (47.9%) and perihilar tract (36.7%), but the mucin-related subtype of invasive IPNB was the main type, intrahepatically (approximately 90%). In the univariate and multivariate Cox regression analysis, age, tumor site, grade and stage, subtype, surgery, and chemotherapy were associated with OS and CSS (P < 0.05).

CONCLUSION

Incidence and IB mortality of invasive IPNB trended steadily downward. The heterogeneity of IPNB comprises site and the tumor’s mucin-producing status.

Clinicopathologic characteristics and long-term prognosis of intraductal papillary neoplasm of the bile duct: a retrospective study

BACKGROUND

Intraductal papillary neoplasm of the bile duct (IPNB) is a premalignant neoplasm that can involve both the intrahepatic and extrahepatic bile ducts. Owing to the low incidence and confusing nomenclature, its clinicopathological features remain controversial. Additionally, only a few studies have reported on the long-term prognosis of IPNB to date. Therefore, the present study aimed to clarify the clinicopathological characteristics and prognosis of IPNB.

METHODS

Medical records of patients with IPNB treated at our hospital between August 2000 and October 2021 were retrospectively reviewed. A database of demographic characteristics, test results, surgical details, pathological findings, and follow-up information was constructed for analysis. Patients were divided into intrahepatic and extrahepatic groups, and dysplasia and invasive carcinoma groups for comparison. Differences between study groups were analyzed using the χ² test, Fisher's exact test, t-test, or Mann-Whitney U test, as appropriate. Cumulative survival rates were estimated using the Kaplan-Meier method.

RESULTS

In total, 43 patients (21 men and 22 women) with IPNB were included in the study. The median age at diagnosis was 62 (54-69) years. Thirty-eight patients underwent surgery. The mean operation time was (269.5 ± 94.9) min. Five patients underwent endoscopic retrograde cholangiopancreatography for biopsy. Twenty-one and 22 patients had intrahepatic and extrahepatic lesions, respectively. The extrahepatic group had more patients with intraluminal masses (p = 0.021) and abnormal bilirubin levels (p = 0.001), but fewer patients with hepatolithiasis (p = 0.021). The operation time was longer in patients with extrahepatic lesions (p = 0.002). Twenty patients had dysplasia and 23 had invasive carcinoma. The invasive carcinoma group had a longer operation time than the dysplasia group (p = 0.004). As of March 2022, 39 patients were followed up, with a mean follow-up time of (56.2 ± 38.2) months. Fifteen patients survived without tumors, two survived with tumors, and 22 patients died. The 1-, 3-, 5-, and 10-year cumulative overall survival rates were 86.9%, 65.8%, 49.8%, and 32.0%, respectively.

CONCLUSIONS

IPNB is a rare bile duct disease that occurs mainly in patients with advanced age. Surgery is the primary treatment strategy. Intrahepatic and extrahepatic lesions, as well as dysplasia and invasive carcinoma have their own unique characteristics. The long-term prognosis of IPNB is generally poor.

Endoscopic Ultrasound in the Diagnosis of Extrahepatic Cholangiocarcinoma: What Do We Know in 2023?

Extrahepatic cholangiocarcinoma (CCA) is a rare and aggressive type of cancer, presenting as a mass or as a biliary stricture. This review summarizes the utility of endoscopic ultrasound (EUS) in the detection, staging, and determination of the differential diagnosis, especially when no cause of bile duct dilatation is revealed by cross-sectional imaging. The EUS detection rate for distal CCAs is higher than that for the proximal CCAs. The accuracy of T staging varies between 60 and 80%, and vascular involvement is correctly assessed by conventional EUS. EUS-tissue acquisition from the primary tumors is reserved for unresectable or metastatic CCA, especially in distal strictures or mass CCAs. For proximal lesions, EUS could be performed as an adjunctive to ERCP sampling when the latter is inconclusive. EUS is not appropriate for assessing the malignant features of lymph nodes in CCAs. Lymph node EUS-tissue acquisition should be performed only if it changes the surgical decision. Perhaps the development of EUS-fine needle biopsy and the detection of molecular genetic alteration will increase the diagnostic yield in CCAs.

Intraductal Papillary Neoplasm of the Bile Duct: A Rare Disease and Presentation

Intraductal papillary neoplasm of the bile duct (IPNB) is a rare disease that occurs anywhere along the bile duct. The disease predominantly occurs in Far East Asia and is very rarely diagnosed and documented in western countries. IPNB presents similarly to obstructive biliary pathology; however, patients can be asymptomatic. Surgical resection of IPNB lesions is crucial for patient survival because IPNB is precancerous and can transform into cholangiocarcinoma. Although potentially curative by excision with negative margins, patients who are diagnosed with IPNB need close monitoring for de novo recurrence of IPNB or other pancreatic-biliary neoplasms. In this case, we present an asymptomatic non-Hispanic Caucasian male who was diagnosed with IPNB.

Intraductal tubulopapillary neoplasms of the bile ducts: identity, clinicopathologic characteristics, and differential diagnosis of a distinct entity among intraductal tumors

Among the mass-forming preinvasive (tumoral intraepithelial) neoplasms of the biliary tract, intraductal tubulopapillary neoplasms (ITPN-Bs) are increasingly being recognized as a separate category. By being intramucosal polypoid proliferations of dysplastic/neoplastic cells, they are highly similar to other members of the "intraductal neoplasms (IDNs)" category (namely, intraductal papillary neoplasms [IPNBs], and intraductal oncocytic papillary neoplasms [IOPNs]); however, they are distinguished by MUC6-expressing nonmucinous cells that lack intestinal differentiation and form striking tubular configuration. Their molecular/genetic profile is also proving to be different with frequent alterations in cell cycle and chromatin remodeling genes, which are quite uncommon in other IDNs and cholangiocarcinomas. Despite the conceptual overlaps, they are also very different from intracholecystic nonmucinous tubular neoplasms (ICTN) of the gallbladder with the latter being associated with Wnt/beta-catenin pathway alterations, and almost never invasive. In contrast, ITPN-Bs are invasive in an estimated 80% of the cases, although even invasive examples often exhibit a protracted course. Invasive carcinomas arising from ITPN-Bs are overall similar to cholangiocarcinomas (including small duct and large duct patterns) but also often have peculiar characteristics such as more nodular-compact (blunt invasion) pattern. Like other IDNs, the ITPN-Bs have also been classified in the past as intraductal-spreading type of cholangiocarcinomas (and they are still regarded as such in some publications). In small biopsies, they are prone to be mistaken as ordinary adenocarcinomas because of their tubular pattern and pancreatobiliary cytology although their relatively monotonous cytology and zones of back-to-back tubule formation can help in their correct identification. Clinical presentation of ITPN-Bs is generally similar to other intraductal neoplasms; however, in the intrahepatic component, they tend to be more nodular than cystic, and their snake-like intraductal growth pattern is often more striking. In the management (diagnosis and treatment) of these tumors that are in essence adenoma-carcinoma sequence, the invasive and noninvasive components ought to be evaluated separately. Minimally invasive examples are commonly curable, and even those more extensively invasive may have a surprisingly good prognosis. In summary, biliary ITPNs form a distinct category not only clinicopathologically, immunophenotypically, and molecular-wise but regarding their biological behavior as well.

Intraductal papillary neoplasm of the bile duct: Cytomorphologic and molecular features

BACKGROUND

Intraductal papillary neoplasm of the bile duct (IPNB) is a rare premalignant neoplasm that can progress to invasive adenocarcinoma. In this retrospective study, cases of IPNB were reviewed to examine cytomorphologic and molecular features.

METHODS

IPNB cytology cases with histopathologic confirmation were retrieved from the pathology archives. The cytomorphologic features such as cellularity, architecture, cell type, and cellular details were analyzed.

RESULTS

The cohort included 13 cases (six brushings, six fine-needle aspirations [FNA], and one combined brushing and FNA). The lesions involved common bile duct in nine cases (69%) and hepatic duct in four cases (31%). Original cytological diagnoses included adenocarcinoma (five, 38%), suspicious for adenocarcinoma (one, 8%), neoplasm (three, 23%), atypical (three, 23%), and reactive (one, 8%). The cytomorphologic features included moderate/high cellularity (12, 92%), papillary and/or complex papillary architecture (10, 77%), columnar cells (11, 85%), vacuolated cytoplasm (12, 92%), enlarged nuclei (13, 100%), and fine granular chromatin (12, 92%). Background mucin, necrosis and acute inflammation were seen in four (31%), four (31%), and two (15%) cases, respectively. KRAS testing was performed in nine cases with mutant KRAS found in five (56%).

CONCLUSIONS

Our study demonstrated that IPNB cytology specimens were relatively cellular with a wide spectrum of cytomorphology; however, most cases harbored adenocarcinoma or high-grade dysplasia. The characteristic cytomorphologic features included papillary/complex papillary clusters of columnar cells with vacuolated cytoplasm, enlarged nuclei, and fine granular chromatin in relatively cellular specimens. KRAS mutations identified may have potential diagnostic and therapeutic implications.

Dense GM-CSFRα-expressing immune infiltration is allied with longer survival of intrahepatic cholangiocarcinoma patients

Background

Intrahepatic cholangiocarcinoma (iCCA) is a cancer arising from intrahepatic bile duct epithelium. An iCCA incidence is increasing worldwide; however, the outcome of the disease is dismal. The linkage between chronic inflammation and iCCA progression is well established, but the roles of granulocyte-macrophage colony-stimulating factor (GM-CSF) remain unrevealed. Thus, a better understanding of GM-CSF functions in CCA may provide an alternative approach to CCA treatment.

Methods

Differential GM-CSF and GM-CSFRα mRNA expressions in CCA tissues were investigated by Gene Expression Profiling Interactive Analysis (GEPIA) based on The Cancer Genome Atlas (TCGA) database. The protein expressions and localizations of GM-CSF and its cognate receptor (GM-CSFRα) in iCCA patients' tissues were demonstrated by the immunohistochemistry (IHC) techniques. The survival analyses were performed using Kaplan-Meier survival analysis with log-rank test and Cox proportional hazard regression model for multivariate analysis. The GM-CSF productions and GM-CSFRα expressions on CCA cells were assessed by ELISA and flow cytometry. The effects of GM-CSF on CCA cell proliferation and migration were evaluated after recombinant human GM-CSF treatment. The relationship between GM-CSF or GM-CSFRα level and related immune cell infiltration was analyzed using the Tumor Immune Estimation Resource (TIMER).

Results

GEPIA analysis indicated GM-CSF and GM-CSFRα expressions were higher in CCA tissues than in normal counterparts, and high GM-CSFRα was related to the longer disease-free survival of the patients (p < 0.001). IHC analysis revealed that CCA cells differentially expressed GM-CSF, while GM-CSFRα was expressed on cancer-infiltrating immune cells. The patient whose CCA tissue contained high GM-CSF expressed CCA, and moderate to dense GM-CSFRα-expressing immune cell infiltration (ICI) acquired longer overall survival (OS) (p = 0.047), whereas light GM-CSFRα-expressing ICI contributed to an increased hazard ratio (HR) to 1.882 (95% CI [1.077-3.287]; p = 0.026). In non-papillary subtype, an aggressive CCA subtype, patients with light GM-CSFRα-expressing ICI had shorter median OS (181 vs. 351 days; p = 0.002) and the HR was elevated to 2.788 (95% CI [1.299-5.985]; p = 0.009). Additionally, TIMER analysis demonstrated GM-CSFRα expression was positively correlated with neutrophil, dendritic cell, and CD8+ T cell infiltrations, though it was conversely related to M2-macrophage and myeloid-derived suppressor cell infiltration. However, the direct effects of GM-CSF on CCA cell proliferation and migration were not observed in the current study.

Conclusions

Light GM-CSFRα-expressing ICI was an independent poor prognostic factor for iCCA patients. Anti-cancer functions of GM-CSFRα-expressing ICI were suggested. Altogether, the benefits of acquired GM-CSFRα-expressing ICI and GM-CSF for CCA treatment are proposed herein and require elucidation.

Pathology of Cholangiocarcinomas

Cholangiocarcinomas (CCA) are heterogeneous tumors that arise from epithelial cells of the biliary tract. They represent the second primary liver malignancy, after hepatocellular carcinoma. Recent epidemiological data show an increased incidence of intrahepatic CCA without any identified causes. According to their location on the biliary tract, intrahepatic, perihilar (p) and distal (d) CCA can be individualized. Intrahepatic CCA (iCCA) are subdivided into small duct type iCCA and large duct type iCCA, according to the level or size of the biliary duct affected. These two subgroups are characterized by distinct risk factors, gross aspect, histopathological and molecular features, and therapeutic management. The role of biopsy in iCCA is to confirm the diagnosis and to eliminate various differential diagnostics, in particular, metastases. In p/d CCA, biopsy requires more invasive approaches, and tissue samples are difficult to obtain, leading to a high rate of false negatives. In this review, we will discuss the different classifications of CCA (anatomical and macroscopic). We will describe the various microscopic and phenotypic subtypes of CCA. Finally, we will deal with their mode of extension, the role of biopsy and pre-neoplastic lesions.

Development of extrahepatic bile ducts and mechanisms of tumorigenesis: Lessons from mouse models

The biliary system is a highly branched tubular network consisting of intrahepatic bile ducts (IHBDs) and extrahepatic bile ducts (EHBDs). IHBDs are derived from hepatic progenitor cells, while EHBDs originate directly from the endoderm through a separate branching morphogenetic process. Traits that are important for cancer are often found to overlap in developmental and other processes. Therefore, it has been suggested that intrahepatic cholangiocarcinomas (iCCAs) and extrahepatic cholangiocarcinomas (eCCAs) have different developmental mechanisms. While much evidence is being gathered on the mechanism of iCCAs, the evidence for eCCA is still very limited. The main reason for this is that there are very few appropriate animal models for eCCA. We can gain important insights from these animal models, particularly genetically engineered mouse models (GEMMs). GEMMs are immunocompetent and mimic human CCA subtypes with a specific mutational pattern, allowing the development of precancerous lesions, that is, biliary intraepithelial neoplasia (BilIN) and intraductal papillary neoplasm of the bile duct (IPNB). This review provides a summary of the pathogenesis and mechanisms of eCCA that can be revealed by GEMMs. Furthermore, we discuss several clinical questions, such as whether BilIN and IPNB really become malignant, whether the peribiliary gland is the origin of eCCAs, and others.

Clinicopathological Features and Long-Term Outcomes of Intraductal Papillary Neoplasms of the Bile Duct of the Liver: Single-Institution Experience with 146 Patients

BACKGROUND

Intraductal papillary neoplasm of the bile duct (IPNB) has a wide range of histopathology and intra- and extrahepatic tumor locations.

METHODS

This retrospective single-center study evaluated the clinicopathological features and long-term outcomes of 146 patients with IPNB of the liver (IPNB-L) who underwent hepatic resection between January 2002 and June 2019.

RESULTS

The 146 patients included 97 (66.4%) men and 49 (33.6%) women, of mean age 64.3 ± 8.0 years. Seventy-two (49.3%) patients were incidentally diagnosed, with no specific symptoms, and 18 (12.3%) were found to have hepatolithiasis. Sixty-one (41.8%) and two (1.4%) patients underwent concurrent bile duct resection and pancreaticoduodenectomy, respectively, and 130 (89.0%) underwent R0 resection. Low-grade and high-grade intraepithelial neoplasia, and invasive carcinoma were identified in 26 (17.8%), 50 (34.2%), and 70 (47.9%) patients, respectively. Five-year tumor recurrence and patient survival rates were 8.4% and 93.9%, respectively, in patients with high-grade neoplasia; and 41.5% and 72.3%, respectively, in patients with invasive carcinoma. CA19-9 > 37 U/mL and R1 resection were independent risk factors for tumor recurrence and reduced survival in patients with carcinoma. The combination of hypermetabolic fluorodeoxy-glucose-positron emission tomography (FDG-PET) or elevated CA19-9 showed a sensitivity of 91.8% and a specificity of 61.9% for the prediction of IPNB-L with high-grade neoplasia and carcinoma.

CONCLUSIONS

IPNB-L is a rare type of intrahepatic biliary neoplasm that can range histologically from benign disease to invasive carcinoma. Surgical curability is the most important prognostic factor, thus aggressive resection is highly recommended to achieve R0 resection.

A case of undifferentiated carcinoma of the gallbladder with severe inflammation and difficult preoperative chemotherapy

Undifferentiated carcinoma (UC) is relatively rare among gallbladder cancers, and the prognosis is poor compared to gallbladder adenocarcinoma. We report a 64-year-old man with gallbladder UC who underwent radical surgery and achieved long-term survival. He presented with a chief complaint of abdominal distension and loss of appetite. An abdominal computed tomography (CT) scan revealed a gallbladder tumor with a major axis of 120 mm that appeared to directly infiltrate the hepatic bed. No major vascular infiltration was noted, but the left and right intrahepatic bile ducts were dilated. On admission, the serum CRP level was 16.5 mg/dL; cholangitis and cholecystitis were suspected. He was hospitalized, treated with antibiotics, and underwent bile duct drainage; however, inflammation recurred and chemotherapy was not possible. Thus, three right liver areas, the caudate lobe, and the gallbladder were extirpated. Histopathologic examination showed a 130 × 90 mm tumor with extensive infiltration, hemorrhage, and necrosis in the liver. In the area occupied by the tumor, multinucleated cell proliferation, and polygonal and spindle-shaped tumor cells were noted. Based on the above findings, a diagnosis of UC was established. Postoperatively, gemcitabine and cisplatin were continued as adjuvant chemotherapy. No tumor recurrence has been detected after 24 months of follow-up care.

A Review of Mucinous Cystic and Intraductal Neoplasms of the Pancreatobiliary Tract

CONTEXT.—

Although most pancreatic and bile duct neoplasms are solid, mucinous cystic neoplasms and intraductal neoplasms have been increasingly recognized even when clinically silent, thanks to the increased use of sensitive imaging techniques. Cystic and intraductal neoplasms of the pancreas are often resectable and curable and constitute about 5% of all pancreatic neoplasms. Owing to their preinvasive nature and different biology, recognition of these entities remains a major priority. Mucinous cystic neoplasms are histologically and clinically distinct from other cystic pancreatic neoplasms. Pancreatic intraductal neoplasms encompass 3 major entities: intraductal papillary mucinous neoplasm, intraductal oncocytic papillary neoplasm, and intraductal tubulopapillary neoplasm. Intraductal papillary neoplasms of bile ducts are also preinvasive mass-forming neoplasms with both similarities and differences with their pancreatic counterparts. All of these pancreatobiliary neoplasms have diverse and distinctive clinicopathologic, genetic, and prognostic variations.

OBJECTIVE.—

To review the clinical, pathologic, and molecular features of mucinous cystic and intraductal neoplasms of the pancreatobiliary tract.

DATA SOURCES.—

Literature review, diagnostic manuals, and guidelines.

CONCLUSIONS.—

This review will briefly describe well-known clinical and pathologic features and will focus on selected recently described aspects of morphology, grading, classification, and genomic alterations of cystic and intraductal neoplasms of the pancreatobiliary tract.

Integrative analysis reveals early and distinct genetic and epigenetic changes in intraductal papillary and tubulopapillary cholangiocarcinogenesis

OBJECTIVE

A detailed understanding of the molecular alterations in different forms of cholangiocarcinogenesis is crucial for a better understanding of cholangiocarcinoma (CCA) and may pave the way to early diagnosis and better treatment options.

DESIGN

We analysed a clinicopathologically well-characterised patient cohort (n=54) with high-grade intraductal papillary (IPNB) or tubulopapillary (ITPN) neoplastic precursor lesions of the biliary tract and correlated the results with an independent non-IPNB/ITPN associated CCA cohort (n=294). The triplet sample set of non-neoplastic biliary epithelium, precursor and invasive CCA was analysed by next generation sequencing, DNA copy number and genome-wide methylation profiling.

RESULTS

Patients with invasive CCA arising from IPNB/ITPN had better prognosis than patients with CCA not associated with IPNB/ITPN. ITPN was localised mostly intrahepatic, whereas IPNB was mostly of extrahepatic origin. IPNB/ITPN were equally associated with small-duct and large-duct type intrahepatic CCA. IPNB exhibited mutational profiles of extrahepatic CCA, while ITPN had significantly fewer mutations. Most mutations were shared between precursor lesions and corresponding invasive CCA but ROBO2 mutations occurred exclusively in invasive CCA and CTNNB1 mutations were mainly present in precursor lesions. In addition, IPNB and ITPN differed in their DNA methylation profiles and analyses of latent methylation components suggested that IPNB and ITPN may have different cells-of-origin.

CONCLUSION

Integrative analysis revealed that IPNB and ITPN harbour distinct early genetic alterations, IPNB are enriched in mutations typical for extrahepatic CCA, whereas ITPN exhibited few genetic alterations and showed distinct epigenetic profiles. In conclusion, IPNB/ITPN may represent a distinctive, intermediate form of intrahepatic and extrahepatic cholangiocarcinogenesis.

Diagnostic and prognostic impact of fluorodeoxyglucose-positron emission tomography in diagnosing intraductal papillary neoplasms of the bile duct of the liver

Purpose

Malignant intraductal papillary neoplasm of the bile duct of the liver (IPNB-L) cannot readily be diagnosed through preoperative CT or MRI, but fluorodeoxyglucose (FDG)-PET is a viable alternative. This study evaluated the diagnostic and prognostic impacts of FDG-PET in patients with IPNB-L.

Methods

This was a retrospective single-center study of 101 IPNB-L patients who underwent hepatectomy between 2010 and 2019.

Results

Mean age was 64.4 ± 8.3 years and 76 (75.2%) were male. Anatomical hepatic resection was performed in 99 (98.0%). Concurrent bile duct resection and pancreaticoduodenectomy were performed in 41 (40.6%) and 1 (1.0%), respectively. R0 and R1 resections were performed in 88 (87.1%) and 13 (12.9%), respectively. Low-grade intraepithelial neoplasia and high-grade neoplasia/invasive carcinoma were diagnosed in 19 (18.8%) and 82 (81.2%), respectively. Median FDG-PET maximal standardized uptake values (SUVmax) in low-grade neoplasia and high-grade neoplasia/carcinoma were 3.6 (range, 1.7–7.6) and 5.2 (range, 1.5–18.7) (P = 0.019), respectively. Receiver operating characteristic curve analysis of SUVmax showed area under the curve of 0.674, with sensitivity of 84.2% and specificity of 47.4% at SUVmax cutoff of 3.0. This cutoff had no significant influence on tumor recurrence (P = 0.832) or patient survival (P = 0.996) in patients with IPNB-L of high-grade neoplasia or invasive carcinoma.

Conclusion

IPNB-L is a rare type of biliary neoplasm and encompasses a histological spectrum ranging from benign disease to invasive carcinoma. An FDG-PET SUVmax cutoff of 3.0 appears to effectively discern high-grade neoplasia/carcinoma from low-grade neoplasia, which will assist with the surgical strategy for these cases.

Choledochoscopy: An update

Choledochoscopy, or cholangioscopy, is an endoscopic procedure for direct visualization within the biliary tract for diagnostic or therapeutic purposes. Since its conception in 1879, many variations and improvements are made to ensure relevance in diagnosing and managing a range of intrahepatic and extrahepatic biliary pathologies. This ranges from improved visual impression and optical guided biopsies of indeterminate biliary strictures and clinically indistinguishable pathologies to therapeutic uses in stone fragmentation and other ablative therapies. Furthermore, with the evolving understanding of biliary disorders, there are significant innovative ideas and techniques to fill this void, such as nuanced instances of biliary stenting and retrieving migrated ductal stents. With this in mind, we present a review of the current advancements in choledo-choscopy with new supporting evidence that further delineates the role of choledochoscopy in various diagnostic and therapeutic interventions, complications, limitations and put forth areas for further study.

Recurrent intraductal papillary neoplasm of the bile duct due to intraductal dissemination: a case report and literature review

Background

Intraductal papillary neoplasm of the bile duct (IPNB) is a subtype of biliary tumor. The 5-year survival rate of patients with IPNB who underwent curative resection is 81%. However, IPNB is known to often recur in other parts of the bile duct. Nevertheless, its mechanism remains poorly understood. Herein, we report the case of a patient with recurrent IPNB, which was considered to be attributed to intraductal dissemination in the common bile duct at 12 months after curative resection. We also made a review of the existing literature.

Case presentation

A 69-year-old man was referred to our hospital for the evaluation and dilation of an intrahepatic bile duct (IHBD) mass. Computed tomography (CT) findings confirmed a mass in the left hepatic duct. Left trisectionectomy, extrahepatic bile duct resection with biliary reconstruction, and regional lymph node dissection were performed. Intraoperative examination of the resection margin at the common bile duct and posterior segmental branch of the hepatic duct was negative for the presence of malignant cells. Histologically, the tumor showed intraductal papillary growth of the mucinous epithelium and was diagnosed as non-invasive IPNB. It had a papillary structure with atypical epithelial cells lined up along the neoplastic fibrovascular stalks. Immunohistochemically, this was as a gastric-type lesion. At 12 postoperative months, CT revealed a 1.5-cm mass in the lower remnant common bile duct. We performed subtotal stomach-preserving pancreaticoduodenectomy. The tumor exhibited papillary growth and was microscopically and immunohistochemically similar to the first tumor. At approximately 16 months after the patient’s second discharge, CT showed an abdominal mass at the superior mesenteric plexus, which was diagnosed as recurrent IPNB. Chemotherapy is ongoing, and the patient is still alive. In this case, as described in many previous reports, IPNB recurred below the primary lesion in the bile duct.

Conclusion

Based on our review of previous reports on IPNB recurrence, intraductal dissemination was considered one of the mechanisms underlying recurrence after multicentric development. Considering the high frequency and oncological conversion of recurrence in IPNB, regular follow-up examination is essential to achieve better prognosis in patients with recurrent IPNB.

Mucin-producing Cystic Hepatobiliary Neoplasms: Updated Nomenclature and Clinical, Pathologic, and Imaging Features

Cystic hepatobiliary neoplasms with mucin-producing epithelium-mucinous cystic neoplasm of the liver (MCN) and intraductal papillary neoplasm of the bile duct (IPNB)-are rare and distinct entities that have unique clinical, pathologic, and imaging features. They are differentiated pathologically by the presence of subepithelial ovarian-like hypercellular stroma (OLS), which is the defining histopathologic feature of MCN. MCN is commonly a benign, large, solitary, symptomatic, multiloculated cystic mass without biliary communication that occurs in middle-aged women. On the other hand, IPNBs are a heterogeneous spectrum of tumors, which are commonly associated with invasive carcinoma, occur in older patients, and can be differentiated from MCN by communication with the biliary tree, intraductal masses, associated biliary ductal dilatation, and absent OLS. Understanding of these rare neoplasms has grown and evolved over time and continues to today, but uncertainty and controversy persist, related to the rarity of these tumors, relatively recent designation as separate entities, inherent clinicopathologic heterogeneity, overlapping imaging features, and the fact that many prior studies likely included MCN and cystic IPNB together as a single entity. Confusion regarding these neoplasms is evident by historical inconsistencies and nonstandardized nomenclature through the years. Awareness of these entities is important for the interpreting radiologist to suggest a particular diagnosis or generate a meaningful differential diagnosis in the appropriate setting, and is of particular significance as MCN and cystic IPNB have overlapping imaging features with other more common hepatobiliary cystic masses but have different management and prognosis. Online supplemental material is available for this article. Work of the U.S. Government published under an exclusive license with the RSNA.

A clinicopathological reappraisal of intraductal papillary neoplasm of the bile duct (IPNB): a continuous spectrum with papillary cholangiocarcinoma in 181 curatively resected cases

BACKGROUND

Intraductal papillary neoplasm of the bile-duct (IPNB) has recently been further subclassified into "so-called IPNBs" (Type-1) and "narrow-sense papillary cholangiocarcinomas" (Type-2), but their differential diagnosis is challenging. This study aimed to reevaluate Type-1 and Type-2 IPNBs.

METHODS

Consecutive patients who underwent papillary bile-duct tumor resection were included. Using six pathological features (location, mucin secretion, histological architecture, histological type, presence of a low/intermediate-dysplasia component, and proportion of the invasive component), all papillary tumors were scored. Tumors scoring 5-6 were classified as Type-1, 0-1 as Type-2, and 2-4 as Type-Unclassifiable.

RESULTS

The 181 papillary bile-duct tumor patients were divided into three groups, consisting of 12 Type-1, 46 Type-2, and 123 Type-Unclassifiable-gray-zone lesions between Type-1 and Type-2 that constituted the largest proportion of papillary tumors. Type-1 tumors were pathologically the least advanced, while the other types showed gradual advancement. The 5-year survival rate was better for patients with Type-1 tumors than for those with Type-Unclassifiable or Type-2 tumors.

CONCLUSION

The scoring system worked well to delineate a continuous spectrum of pathologic features ranging from Type-1, through Type-Unclassifiable, to Type-2, the latter two being challenging to differentially diagnose. Type-1 is regarded as an early neoplasm of Type-Unclassifiable and Type-2.

Current status of diagnosis and therapy for intraductal papillary neoplasm of the bile duct

Bile duct epithelial tumours showing papillary neoplasm in the bile duct lumen are present in the intrahepatic and extrahepatic bile ducts. Clinicopathological images of these tumours are distinctive and diverse, including histological images with a low to high grade dysplasia, infiltrating and noninfiltrating characteristics, excessive mucus production, and similarity to intraductal papillary mucinous neoplasm (IPMN) of the pancreas. The World Health Organization Classification of Tumours of the Digestive System in 2010 named these features, intraductal papillary neoplasm of the bile duct (IPNB), as precancerous lesion of biliary carcinoma. IPNB is currently classified into type 1 that is similar to IPMN, and type 2 that is not similar to IPMN. Many of IPNB spreads superficially, and diagnosis with cholangioscopy is considered mandatory to identify accurate localization and progression. Prognosis of IPNB is said to be better than normal bile duct cancer.

Resection for a Recurrent Mucus-Producing Cholangiocarcinoma After Surgery: a Case Report

Introduction

Intraductal papillary neoplasm of the bile duct (IPNB) is a variant of bile duct carcinoma characterized by intraductal growth. There are few case reports and papers discussing treatment policy and prognosis for cases of postoperative relapse.

Case Presentation

The case subject was a female in her 40s. Due to IPNB with the primary tumor in hepatic left lobe, the patient underwent hepatic left lobe, caudate lobe, and bile duct resection, and biliary tract reconstruction at another institution. Four years later, near the cholangiojejunostomy, a localized recurrence was indicated. Though systemic metastasis was examined with CT, FDG-PET, distant metastasis was not confirmed. As it was believed that resection of the recurrent focal could lead to a long-term survival, the recurrent focal was resected. The resected specimen was a cystic mass with a film, and in a pathologic examination, lymph node tissue was not confirmed in the specimen, while intracystic papilloma of attached liver tissue without continuity was confirmed. The patient has not seen a relapse for 5 years and 5 months after the second surgery.

Conclusion

In a case of localized recurrence after the IPNB surgery, resection should be actively considered.

Intracholecystic papillary neoplasm arising in the cystic duct and extending into common bile duct: a case report

An 83-year-old man without specific symptoms was referred to our hospital for further evaluation and treatment of apparent double primary tumors of the cystic duct and common bile duct. Computed tomography showed contrast-enhanced solid tumors in the cystic duct and common bile duct. Magnetic resonance imaging showed that the bile duct tumor was isointense on T1-weighted images and had low intensity on T2-weighted images. In addition, the bile duct tumor showed high intensity on diffusion-weighted images. Endoscopic ultrasonography revealed the tumor of the common bile duct and endoscopic retrograde cholangiopancreatography demonstrated a filling defect in the bile duct. The cystic duct was not identified on endoscopic ultrasonography or endoscopic retrograde cholangiopancreatography. Transpapillary biopsy of the bile duct tumor showed adenocarcinoma. The patient was diagnosed with double primary tumors of the cystic duct and the common bile duct and underwent subtotal stomach-preserving pancreaticoduodenectomy. Microscopic examination with molecular profiling of the tumors revealed a high-grade noninvasive intracholecystic papillary neoplasm of the cystic duct extending into the common bile duct and forming a tubulopapillary neoplasm with invasion of the common bile duct.

Intraductal papillary mucinous neoplasm of biliary ducts: Literature review and a case report with emphasis on radiological manifestation

Intraductal papillary mucinous neoplasm of the biliary tract (B-IPMN) is an intraductal growing mucin producing tumor that is precursor of cholangiocarcinoma. Dilation of both upstream and downstream biliary ducts is the radiological key feature that is respectively caused by intraductal obstructive growth and massive mucin production. Although B-IPMN is rare, if the radiologist is familiar with its manifestation, can lead to early diagnosis when surgical resection can be curative. Here, we report a long standing pathologically proved case of B-IPMN with emphasis on radiological manifestation during a long time of 13 years across different imaging modalities.

Cystic biliary tumors of the liver: diagnostic criteria and common pitfalls

With major advancements and frequent use of abdominal imaging techniques, hepatic cysts are increasingly encountered in clinical practice. Although the majority of cysts are benign, a small subset represents neoplastic precursors to cholangiocarcinoma. These cystic precursors include intraductal papillary neoplasms of the bile duct (IPNB) and mucinous cystic neoplasms of the liver (MCN-L), and bear striking pathologic resemblance to corresponding cystic neoplastic precursors within the pancreas. This review examines the salient clinical, gross, microscopic and molecular features of IPNBs and MCN-Ls, and, in particular, provides histopathologic comparison to their pancreatic counterparts. Considering these neoplasms may be diagnostically challenging, we also discuss other hepatic lesions within the differential diagnosis, and the potential for molecular methods to improve their preoperative evaluation and the early detection of cholangiocarcinoma.

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.

Premalignant lesions of the extrahepatic biliary tract. A territory to be explored hand in hand with cholangioscopy

The biliary mucosa, both intrahepatic and extrahepatic, is lined by a single layer of columnar cells with oval nuclei near the base and a slightly eosinophilic cytoplasm. Although normal biliary ducts have no goblet cells, there are periductal mucous glands lined by mucus-producing cuboidal cells, with mucin from these glands draining to the lumen of bile ducts.

Intraductal Papillary Neoplasm of the Bile Ducts: Case Reports with Review of the Literature

Intraductal papillary neoplasm of the bile duct (IPNB) is a rare variant of bile duct tumors, which is a counterpart of pancreatic intraductal papillary mucinous neoplasm (IPMN). These tumors need to be differentiated from other common bile duct tumors such as cholangiocarcinoma, as IPNB carries a better prognosis. A combination of enhancing intraluminal papillary filling defect, demonstrating washout and associated upstream and downstream biliary dilation, should raise the suspicion of IPNB.

Clinicopathological characteristics of intraductal papillary neoplasm of the bile duct: a Japan-Korea collaborative study

BACKGROUND

The prevalent location and incidence of intraductal papillary neoplasm of the bile duct (IPNB) and invasive carcinoma associated with them have varied markedly among studies due to differences in diagnostic criteria and tumor location.

METHODS

IPNBs were classified into two types: Type 1 IPNB, being histologically similar to intraductal papillary mucinous neoplasm of the pancreas, and Type 2 IPNB, having a more complex histological architecture with irregular papillary branching or foci of solid-tubular components. Medical data were evaluated.

RESULTS

Among 694 IPNB patients, 520 and 174 had Type 1 and Type 2, respectively. The levels of AST, ALT, ALP, T. Bil, and CEA were significantly higher in patients with Type 2 than in those with Type 1. Type 1 IPNB was more frequently located in the intrahepatic bile duct than Type 2, whereas Type 2 was more frequently located in the distal bile duct than Type 1 IPNB (P < 0.001). There were significant differences in 5-year cumulative survival rates (75.2% vs 50.9%; P < 0.0001) and 5-year cumulative disease-free survival rates (64.1% vs 35.3%; P < 0.0001) between the two groups.

CONCLUSION

Type 1 and Type 2 IPNBs differ in their clinicopathological features and prognosis. This classification may help to further understand IPNB.

[Cholangiocarcinoma-diagnosis, classification, and molecular alterations]

BACKGROUND

The entity cholangiocarcinoma comprises various malignant epithelial neoplasms of different morphology, etiology, and pathogenesis.

AIM

In this review, the etiology, pathogenesis, diagnostic criteria, classification, and molecular alterations of intra- and extrahepatic cholangiocarcinomas are summarized.

MATERIAL AND METHODS

This review is based on the currently available literature and personal knowledge.

RESULTS AND DISCUSSION

Cholangiocarcinomas are morphologically and molecularly diverse neoplasms that can develop ubiquitously in the biliary tract. Since there is a significant histological and immunohistochemical overlap with frequent liver metastases, a definite diagnosis can often only be rendered in the clinical context. Cholangiocarcinomas are subclassified into intrahepatic (iCCA), perihilar (pCCA), and distal (dCCA) tumors according to macro-anatomical criteria. Recent studies show that there are distinctive molecular differences in particular between iCCA and extrahepatic CCA (eCCA, including pCCA and dCCA). In addition, morphologically well-characterized precursor lesions have been identified, which in various frequencies can be assigned not only to the anatomical classification, but also to certain etiologies. An exact classification is therefore essential, especially with regard to the development of innovative, targeted therapeutic approaches.

Long-term survival after palliative argon plasma coagulation for intraductal papillary mucinous neoplasm of the bile duct

Intraductal papillary mucinous neoplasm of the bile duct (IPNB) is an epithelial tumor that can cause obstructive jaundice and cholangitis due to mucin production. Although the effectiveness of argon plasma coagulation in IPNB treatment has been demonstrated, the long-term effect of the therapy is largely unknown. Here, we have presented a patient with IPNB who underwent argon plasma coagulation with a follow-up period of more than 2 years. A 74-year-old woman was referred to our department for treatment of obstructive jaundice. Endoscopic retrograde cholangiopancreatography revealed marked dilation of intrahepatic and extrahepatic bile ducts and thick mucin drainage from the ampulla of Vater. IPNB was diagnosed pathologically from biopsy specimens. Surgery was not recommended because of the extensive intrahepatic spread of the lesion. Endoscopic sphincterotomy, endoscopic papillary large balloon dilation, and insertion of a metallic stent could not resolve the obstructive jaundice. Finally, argon plasma coagulation with percutaneous cholangioscopy was performed 3 times over 1 month. After treatment, obstructive jaundice was resolved and the patient's clinical condition has been stable for more than 2 years, except for a single episode of transient cholangitis. In conclusion, argon plasma coagulation may be an alternative to surgery for the palliation of jaundice with IPNB.

Clinicopathologic analysis of intraductal papillary neoplasm of bile duct: Korean multicenter cohort study

BACKGROUND

IPNB is very rare disease and most previous studies on IPNB were case series with a small number due to low incidence. The aim of this study is to validate previously known clinicopathologic features of intraductal papillary neoplasm of bile duct (IPNB) based on the first largest multicenter cohort.

METHODS

Among 587 patients previously diagnosed with IPNB and similar diseases from each center in Korea, 387 were included in this study after central pathologic review. We also reviewed all preoperative image data.

RESULTS

Of 387 patients, 176 (45.5%) had invasive carcinoma and 21 (6.0%) lymph node metastasis. The 5-year overall survival was 80.9% for all patients, 88.8% for IPNB with mucosal dysplasia, and 70.5% for IPNB with invasive carcinoma. According to the "Jang & Kim's modified anatomical classification," 265 (68.5%) were intrahepatic, 103 (26.6%) extrahepatic, and 16 (4.1%) diffuse type. Multivariate analysis revealed that tumor invasiveness was a unique predictor for survival analysis. (p = 0.047 [hazard ratio = 2.116, 95% confidence interval 1.010-4.433]).

CONCLUSIONS

This is the first Korean multicenter study on IPNB through central pathologic and radiologic review process. Although IPNB showed good long-term prognosis, relatively aggressive features were also found in invasive carcinoma and extrahepatic/diffuse type.

Multi-serum glycobiomarkers improves the diagnosis and prognostic prediction of cholangiocarcinoma

BACKGROUND

Aberrant glycosylation has been reported to play important roles in progression of cholangiocarcinoma (CCA) and hence the aberrant expressed glycans are beneficial markers for diagnosis and prognostic prediction of CCA.

METHODS

Five CCA-associated glycobiomarkers-carbohydrate antigen 19-9 (CA19-9), carbohydrate antigen-S27 (CA-S27), CCA-associated carbohydrate antigen (CCA-CA), WFA-positive MUC1 (WFA⁺-MUC1), and WFA-positive M2BP (WFA⁺-M2BP), in the sera from CCA patients (N = 138) were determined in comparison with non-CCA control subjects (N = 246).

RESULTS

Receiver operating characteristic analysis suggested the significance of each glycobiomarker in discriminating CCA from non-CCA with area under curve of 0.580-0.777. High levels of CA19-9, CCA-CA, CA-S27, or WFA⁺-MUC1 were associated with poor prognosis and poor survival of CCA patients. Combination of these glycobiomarkers and graded as a GlycoBiomarker (GB)-score could increase the power of the tests in diagnosis than an individual marker with 81% of sensitivity, specificity and accuracy.

CONCLUSIONS

According to the GB-score, these glycobiomarkers not only increased diagnostic power but also discriminated survival of patients indicating the diagnostic and prognostic values of GB-score.

Prognostic Factors for Surgically Resected Intraductal Papillary Neoplasm of the Bile Duct: A Retrospective Cohort Study

BACKGROUND

To date, postoperative prognostic factors for intraductal papillary neoplasm of the bile duct (IPNB) have not been well-established. This study aimed to examine the histopathologic features and postoperative prognosis of the two IPNB subclassifications, as well as factors affecting prognosis, based on the authors' experience at a single institution.

METHODS

The study enrolled 83 patients who underwent surgical resection for pathologically diagnosed IPNB at the authors' institution. The clinicopathologic features and postoperative outcomes for these patients were examined. The study also investigated postoperative prognostic factors for IPNB using uni- and multivariate analyses.

RESULTS

More than half of the tumors (64%) diagnosed as IPNB were early-stage cancer (UICC Tis or T1). However, none were diagnosed as benign. The multivariate analysis showed that lymph node metastasis (hazard ratio [HR], 5.78; p = 0.002) and bile duct margin status with carcinoma in situ (D-CIS; HR, 5.10; p = 0.002) were independent prognostic factors, whereas MUC6 expression showed only a marginal influence on prediction of prognosis (HR, 0.32; p = 0.07). The tumor recurrence rate and the proportion of locoregional recurrence were significantly greater among the patients with D-CIS than among those with negative bile duct margins, including those patients with low-grade dysplasia. The patients with D-CIS showed a significantly poorer prognosis than those with negative bile duct margins (5-year survival, 38% versus 87%; p = 0.0002).

CONCLUSIONS

Evaluation of resected IPNBs showed cancer in all cases. Avoiding positive biliary stumps during surgery, including resection of carcinoma in situ, would improve the prognosis for patients with IPNB.

Branch-type intraductal papillary neoplasm of the bile duct treated with laparoscopic anatomical resection: a case report

Background

Intraductal papillary neoplasm of the bile duct (IPNB) is characterized by an intraluminal, growing papillary tumor covered by neoplastic biliary epithelial cells with a fine fibrovascular core. IPNB was introduced as a precancerous and early neoplastic lesion in the 2010 World Health Organization classification of tumors of the digestive system. IPNB eventually invades the bile duct wall and progresses to invasive cholangiocarcinoma. IPNB resembles intraductal papillary mucinous neoplasm of the pancreas (IPMN), particularly the main pancreatic duct type.

IPNB cases, possibly corresponding to branch-type IPMN, have been recently reported, and these cases involved the peribiliary glands significantly and showed gross cystic dilatation. Small branch-type intrahepatic IPNB often mimics simple liver cysts, making the diagnosis of IPNB difficult. Some literature recommended surgical resection for treatment. Laparoscopic resection is a good treatment option for small tumor. We herein present the case of branch-type IPNB that was treated with laparoscopic anatomical liver resection 5 years after being detected.

Case presentation

A 64-year-old woman was undergoing follow-up for primary aldosteronism. In 2012, follow-up computed tomography (CT) incidentally revealed a 7-mm cystic lesion in segment 8 of the liver. From 2012 to 2017, the cystic lesion kept increasing in size, reaching 17 mm. In 2017, CT also revealed a 13-mm mural nodule in the cyst wall. Therefore, the patient was referred to our department for possible malignancy.

We suspected a branch-type IPNB; however, the mass was small and diagnosis could not be made without performing biopsy. Accordingly, surgical resection was performed for diagnosis and treatment. Because branch-type IPNB might show horizontal spread through the intrahepatic bile duct, we believed that anatomical resection of the liver was appropriate considering the malignant potential of the lesion. Therefore, laparoscopic anatomical resection of segment 8 of the liver was performed. The resected tumor measured 17 mm and was histologically diagnosed as a high-grade IPNB.

Conclusion

Branch-type IPNBs are rare but can potentially lead to malignant tumors. Surgical resection is the treatment of choice, with laparoscopic anatomical resection being a good treatment option for this small tumor.

Biliary intraductal tubule-forming neoplasm: a whole exome sequencing study of MUC5AC-positive and -negative cases

AIMS

Biliary intraductal tubular neoplasms that are non-mucinous and negative for mucin 5AC (MUC5AC) are called intraductal tubulopapillary neoplasms (ITPNs). Intraductal tubular neoplasms with mucinous cytoplasm and MUC5AC positivity also occur and their nature remains unclear, although some pathologists may classify these as 'intraductal papillary neoplasms of the bile duct (IPNBs) of gastric type'. This study aimed to elucidate genetic features of biliary intraductal tubular neoplasms.

METHODS AND RESULTS

Six resected cases of biliary intraductal neoplasm with >70% tubular configuration were characterised by clinicopathological examination and whole exome sequencing, and the findings obtained were compared between MUC5AC-negative (n = 2) and -positive cases (n = 4). The intraductal tumours consisted of the pancreatobiliary-type epithelium with high-grade dysplasia arranged in back-to-back tubules. Both of the two MUC5AC-negative cases were non-invasive neoplasms and developed in the liver, whereas all MUC5AC-positive cases had invasive carcinoma and were present in the intrahepatic (n = 2), perihilar (n = 1) and distal bile ducts (n = 1). In an exome-sequencing study, MUC5AC-negative cases harboured mutations in CTNNB1, SF3B1, BAP1 and BRCA1 (one case each). KRAS mutations were observed in three of four MUC5AC-positive cases (75%) but none of the MUC5AC-negative neoplasms. Compared to published data, known driver genes of other intraductal neoplasms of the pancreatobiliary system (e.g. APC, CTNNB1, STK11, GNAS and PIK3CA) were wild-type in all but one MUC5AC-negative case with CTNNB1 mutation. Chromatin modifiers (ARID1A, BAP1 and KMT2C) were also altered in MUC5AC-positive cases, similar to usual cholangiocarcinomas.

CONCLUSIONS

This exome-sequencing study suggested that MUC5AC-negative biliary ITPNs are genetically distinct from pancreatic ITPNs and IPNBs. They may also biologically differ from MUC5AC-positive tubular neoplasms despite morphological resemblance.

Characterization of Intraductal Papillary Neoplasm of the Bile Duct with Respect to the Histopathologic Similarities to Pancreatic Intraductal Papillary Mucinous Neoplasm

Intraductal papillary neoplasms of the bile duct (IPNBs) are known to show various pathologic features and biological behaviors. Recently, two categories of IPNBs have been proposed based on their histologic similarities to pancreatic intraductal papillary mucinous neoplasms (IPMNs): type 1 IPNBs, which share many features with IPMNs; and type 2 IPNBs, which are variably different from IPMNs. The four IPNB subtypes were re-evaluated with respect to these two categories. Intestinal IPNBs showing a predominantly villous growth may correspond to type 1, while those showing papillay-tubular or papillay-villous growth correspond to type 2. Regarding gastric IPNB, those with regular foveolar structures with varying numbers of pyloric glands may correspond to type 1, while those with papillary-foveolar structures with gastric immunophenotypes and complicated structures may correspond to type 2. Pancreatobiliary IPNBs that show fine ramifying branching may be categorized as type 1, while others containing many complicated structures may be categorized as type 2. Oncocytic type, which displays solid growth or irregular papillary structures, may correspond to type 2, while papillary configurations with pseudostratified oncocytic lining cells correspond to type 1. Generally, type 1 IPNBs of any subtype develop in the intrahepatic bile ducts, while type 2 IPNBs develop in the extrahepatic bile duct. These findings suggest that IPNBs arising in the intrahepatic ducts are biliary counterparts of IPMNs, while those arising in the extrahepatic ducts display differences from prototypical IPMNs. The recognition of these two categories of IPNBs with reference to IPMNs and their anatomical location along the biliary tree may deepen our understanding of IPNBs.