Intraductal papillary neoplasms of the bile duct consist of two distinct types specifically associated with clinicopathological features and molecular phenotypes

Prognostic factors for intraductal papillary neoplasm of the bile duct following surgical resection: a systematic review and meta-analysis

Intraductal papillary neoplasm of the bile duct (IPNB) is a biliary neoplasm characterized by intraductal papillary growth and varying degrees of malignant transformation. This study aimed to identify effective prognostic factors (PFs) for predicting the prognosis of IPNB after surgical resection, addressing the gap in the higher level evidence. We systematically searched databases from their inception to October 10, 2023. Data on 12 predetermined PFs were collected and subjected to a meta-analysis. Forest plots were used to summarize the findings. Fifteen studies with a total of 2311 patients were included. Among the PFs examined, extrahepatic tumor location (HR, 2.97; 95% CI 1.68-5.23), subclassification type 2 (HR, 2.62; 95% CI 1.45-4.76), R1 resection (HR, 2.47; 95% CI 1.73-3.51), elevated CA19-9 level (HR, 3.25; 95% CI 1.91-5.54), tumor multiplicity (HR, 2.65; 95% CI 1.40-5.02), and adjacent organ invasion (HR, 3.17; 95% CI 2.01-5.00) were associated with a poorer prognosis. Additionally, the combined HR values indicated that lymph node metastasis and poor tumor differentiation were linked to a worse prognosis, although both exhibited significant heterogeneity. Our study offers valuable insights for enhancing postoperative prognostication and treatment decision-making for IPNB patients with IPNB. These findings warrant further validation in future prospective studies.

Multiple intraductal papillary neoplasms of bile duct diagnosed based on endoscopic ultrasonography and peroral cholangioscopy findings

A man in his 30s was referred to our department for evaluation of bile duct stricture and removal of an intrahepatic bile duct stone. Five years before his presentation, he underwent left hepatectomy for a giant hepatic hemangioma. There were no abnormalities in blood biochemical tests. Magnetic resonance cholangiopancreatography showed one 5 mm oval defect in region B6 and two 8 mm semicircular defects in the hilar bile duct. Endoscopic ultrasound revealed a 3.5 mm hypoechoic focal raised lesion in the hilar bile duct. Oral cholangioscopy revealed his two lesions in the hilar bile duct as white papillary elevations with mucus production. The pathological diagnosis of intraductal papillary neoplasm was determined (low-grade dysplasia, type 1, gastric type). After 1 and a half years, no expansion of the bile duct lesion was observed. Initially, it was thought to be a benign stenosis after liver resection, but based on the results of endoscopic ultrasound, we suspected a tumorous lesion, and we were able to make an accurate diagnosis, including histological type, using transoral cholangioscopy.

Clinicopathological features and surgical treatments of intraductal papillary neoplasm of the bile duct: a case report and literature review

Intraductal papillary neoplasm of bile duct (IPNB), as a precancerous lesion of cholangiocarcinoma, is a rare biliary tract tumor. A 66-year-old female patient was found to have a bile duct mass by routine examination. The liver function tests and tumor markers were normal. Imaging findings revealed a 2.6 cm mass in the common hepatic duct, accompanied by dilatation of both intrahepatic and extrahepatic bile ducts. The patient underwent open extrahepatic bile duct resection, cholecystectomy and Roux-en-Y hepaticojejunostomy. We also conducted a literature review to summarize the clinicopathological features and surgical treatments of IPNB.

Neoplastic Progression in Intraductal Papillary Neoplasm of the Bile Duct

CONTEXT.—

Intraductal papillary neoplasm of the bile duct (IPNB) is classified into types 1 and 2 based on criteria proposed in 2019. Recent studies investigated the clinicopathologic and molecular features of IPNB, which contributed to a more detailed understanding of this undercharacterized neoplasm.

OBJECTIVE.—

To summarize driver gene mutations, radiologic tumor evolution, and a potentially unique pattern of tumor progression in IPNB.

DATA SOURCES.—

Data were derived from a literature review and personal clinical and research experiences.

CONCLUSIONS.—

In contrast to de novo cholangiocarcinoma, type 1 IPNB often has mutations in APC, CTNNB1, STK11, and GNAS. These molecular features are shared with intraductal papillary mucinous neoplasm of the pancreas; however, the frequencies of individual gene abnormalities differ between these 2 neoplasms. A radiologic review of sequential images suggested that type 1 IPNB is a slow-growing neoplasm, with an ∼1-cm increase in size every 2 to 3 years, and remains in a noninvasive state for many years. A similar papillary neoplasm may develop in the biliary tree years after the complete surgical resection of IPNB. The second neoplasm has the same genetic abnormalities as the first neoplasm, indicating intrabiliary implantation rather than multifocal lesions. In contrast to type 1 IPNB, most cases of type 2 IPNB have invasive malignancy at the initial presentation. Type 2 IPNB shares many clinicopathologic and molecular features with de novo cholangiocarcinoma, questioning the distinctness of this tumor entity. The molecular mechanisms underlying malignant transformation in IPNB warrant further study.

Intraductal Papillary Neoplasms of the Bile Duct: Clinical Case Insights and Literature Review

BACKGROUND

Intraductal papillary neoplasms of the bile duct (IPNB) are rare precancerous lesions with implications for the development of cholangiocarcinoma (CCA). Recognizing IPNB and managing its recurrence pose challenges in clinical practice. We present two cases. Case 1: a 60-year-old man presented with an 8 × 8 × 9 cm hepatic cyst initially suspected to be a hydatid cyst. Histology post-resection revealed an IPNB with foci of adenocarcinoma. Despite negative oncologic margins, recurrence occurred eight years later as an rT2N0 lesion. Surgical resection was performed without adjuvant chemotherapy, resulting in the patient's survival at 48 months post-surgery. Case 2: a 28-year-old female with cognitive impairment was admitted with pulmonary embolism and a liver lesion diagnosed as a simple cyst. Subsequent evaluation revealed adenocarcinoma with local metastases, extensive vascular involvement, and thrombosis. Despite aggressive management, including thrombectomy and chemotherapy, the patient's condition deteriorated, leading to hepatic failure and eventual demise.

CONCLUSION

IPNB represents a rare premalignant subtype with a propensity for progression to CCA. R0 surgical resection typically offers favorable oncological outcomes with a minimal recurrence risk. Surgical intervention for localized resectable recurrence is both safe and feasible. International registries tracking IPNB recurrence are essential for advancing understanding and optimizing diagnosis, management, and treatment strategies.

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.

Clonal analysis of metachronous double biliary tract cancers

The molecular mechanisms underpinning the development of metachronous tumors in the remnant bile duct following surgical resection of primary biliary tract carcinomas (BTCs) are unknown. This study aimed to elucidate these mechanisms by evaluating the clinicopathologic features of BTCs, the alterations to 31 BTC-related genes on targeted sequencing, and the aberrant expression of p53, p16, SMAD4, ARID1A and β-catenin on immunohistochemistry. Twelve consecutive patients who underwent resection of metachronous BTCs following primary BTC resection with negative bile duct margins were enrolled. Among the 12 metachronous tumors, six exhibited anterograde growth in the lower portion and six exhibited retrograde growth in the upper portion of the biliary tree. Surgical resection of metachronous BTCs resulted in recurrence-free survival in seven, local recurrence in five, and death in two patients. Nine achieved 5-year overall survival after primary surgery. Molecular analyses revealed that recurrently altered genes were: TP53, SMAD4, CDKN2A, ELF3, ARID1A, GNAS, NF1, STK11, RNF43, KMT2D and ERBB3. Each of these was altered in at least three cases. A comparison of the molecular features between 12 paired primary and metachronous BTCs indicated that 10 (83%) metachronous tumors developed in clonal association with corresponding primary tumors either successionally or phylogenically. The remaining two (17%) developed distinctly. The successional tumors consisted of direct or evolved primary tumor clones that spread along the bile duct. The phylogenic tumors consisted of genetically unstable clones and conferred a poor prognosis. Metachronous tumors distinct from their primaries harbored fewer mutations than successional and phylogenic tumors. In conclusion, over 80% of metachronous BTCs that develop following primary BTC resection are probably molecularly associated with their primaries in either a successional or a phylogenetic manner. Comparison between the molecular features of a metachronous tumor and those of a preceding tumor may provide effective therapeutic clues for the treatment of metachronous BTC. © 2024 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Interobserver agreement of pathologic classification and grading of tumoral intraductal pre-invasive neoplasms of the bile duct

Current WHO terminology and recent publications have classified tumoral (grossly visible) intraductal pre-invasive neoplasms of bile duct (TIDN) into three categories: intraductal papillary neoplasm of bile duct (IPNB), intraductal papillary oncocytic neoplasm (IOPN), and intraductal tubulopapillary neoplasm (ITPN). A total of 227 cases of TIDN and related lesions ≥3 mm in height were examined by 10 biliary pathologists referring to these 3 categories and two pathologic gradings: two-tiered system (low- and high-grade dysplasia) and modified types 1 and 2 subclassification. Among them, IPNB was the most frequent (183 cases), followed by IOPN (28 cases), while ITPN was rare (2 cases), and interobserver agreement in this classification was "substantial" (κ-value, 0.657). The interobserver agreement of two-tiered grading system of TIDN was "slight" (κ-value, 0.201), while that of modified types 1 and 2 subclassification was "moderate" (κ-value, 0.515), and 42 % were of type 1, and 58 % were of type 2. Type 1 TIDN showed occasional stromal invasion (6.7 %), whereas type 2 TIDN was frequently associated with stromal invasion (49.6 %) (p < 0.01). In conclusion, the classification of TIDN into three categories and modified types 1 and 2 subclassification are a practically applicable classification and grading system for TIDN.

Gene Rearrangement and Expression of PRKACA and PRKACB Govern Morphobiology of Pancreatobiliary Oncocytic Neoplasms

Intraductal oncocytic papillary neoplasms (IOPNs) are distinct from intraductal papillary mucinous neoplasms based on characteristic morphologic and genetic features represented by fusion genes involving PRKACA or PRKACB (PRKACA/B). However, pancreatic and biliary tumors with partial oncocytic features are often encountered clinically, and their molecular features are yet to be clarified. This study included 80 intraductal papillary neoplasms: 32 tumors with mature IOPN morphology (typical), 28 with partial or subclonal oncocytic features (atypical), and 20 without oncocytic features (control). We analyzed PRKACA/B fusion genes, including ATP1B1::PRKACA, DNAJB1::PRKACA, and ATP1B1::PRKACB, by reverse-transcription PCR; mRNA expression of fusion genes and nonrearranged PRKACA/B genes by quantitative reverse-transcription PCR; mutations in KRAS, BRAF, and GNAS by targeted sequencing or droplet digital PCR; and the expression of cyclic adenosine monophosphate (cAMP)-dependent protein kinase catalytic subunits α (PRKACA) and β (PRKACB), phosphorylated cAMP response element-binding protein, and aberrations of p16, p53, SMAD4, STK11, and β-catenin by immunohistochemistry. PRKACA/B fusion genes were detected in 100% (32/32) of typical, 46% (13/28) of atypical, and 0% (0/20) of control (P < .05). Expression of PRKACA, PRKACB, and phosphorylated cAMP response element-binding protein was upregulated in neoplasms with PRKACA/B fusion genes (P < .05). mRNA expression of the PRKACA/B fusion genes and protein expression of PRKACA or PRKACB tended to be higher in typical than in atypical cases (mRNA, P = .002; protein expression, P = .054). In some atypical neoplasms with mixed subtypes, PRKACA/B fusion genes were superimposed exclusively on oncocytic components. Typical IOPNs harbored fewer KRAS and GNAS mutations than control samples and fewer alterations in p53 and STK11 than atypical samples (P < .05). In conclusion, PRKACA/B fusion genes not only are the characteristic drivers of IOPNs but also play a crucial role in the development of subclonal oncocytic neoplasms. Moreover, oncocytic morphology is strongly associated with upregulation of PRKACA/B, which may provide clues for potential therapeutic options.

Expert Consensus on Pathological Diagnosis of Intrahepatic Cholangiocarcinoma (2022 version)

Intrahepatic cholangiocarcinoma (iCCA) can originate from the large bile duct group (segment bile ducts and area bile ducts), small bile duct group (septal bile ducts and interlobular bile ducts), and terminal bile duct group (bile ductules and canals of Hering) of the intrahepatic biliary tree, which can be histopathological corresponding to large duct type iCCA, small duct type iCCA and iCCA with ductal plate malformation pattern, and cholangiolocarcinoma, respectively. The challenge in pathological diagnosis of above subtypes of iCCA falls in the distinction of cellular morphologies, tissue structures, growth patterns, invasive behaviors, immunophenotypes, molecular mutations, and surgical prognoses. For these reasons, this expert consensus provides nine recommendations as a reference for standardizing and refining the diagnosis of pathological subtypes of iCCA, mainly based on the 5th edition of the World Health Organization Classification of Tumours of the Digestive System.

Tumoral Intraductal Neoplasms of the Bile Ducts Comprise Morphologically and Genetically Distinct Entities

CONTEXT.—

Tumoral (grossly visible) intraductal neoplasms of the bile ducts are still being characterized.

OBJECTIVE.—

To investigate their morphologic, immunohistochemical, and molecular features.

DESIGN.—

Forty-one cases were classified as gastric-, intestinal-, pancreatobiliary-type intraductal papillary neoplasm (IPN), intraductal oncocytic papillary neoplasm (IOPN), or intraductal tubulopapillary neoplasm (ITPN) on the basis of histology. All neoplasms were subjected to targeted next-generation sequencing.

RESULTS.—

The mean age at diagnosis was 69 years (42-81 years); male to female ratio was 1.3. Most neoplasms (n = 23, 56%) were extrahepatic/large (mean size, 4.6 cm). The majority (n = 32, 78%) contained high-grade dysplasia, and 68% (n = 28) revealed invasion. All gastric-type IPNs (n = 9) and most ITPNs/IOPNs showed consistent colabeling for CK7/MUC6, which was less common among others (P = .004). Intestinal-type IPNs (n = 5) showed higher rates of CK20 expression than others (P < .001). Overall, the most commonly mutated genes included TP53 and APC, while copy number variants affected ELF3 and CDKN2A/B. All gastric-type IPNs contained an alteration affecting the Wnt signaling pathway; 7 of 9 (78%) showed aberrations in the MAPK pathway. Mutations in APC and KRAS were common in gastric-type IPNs as compared with others (P = .01 for both). SMAD4 was more frequently mutated in intestinal-type IPNs (P = .02). Pancreatobiliary-type IPNs (n = 14) exhibited frequent alterations in tumor suppressor genes including TP53, CDKN2A/B, and ARID2 (P = .04, P = .01 and P = .002, respectively). Of 6 IOPNs analyzed, 3 (50%) revealed ATP1B1-PRKACB fusion. ITPNs (n = 6) showed relatively few recurrent genetic aberrations. Follow-up information was available for 38 patients (median, 58.5 months). The ratio of disease-related deaths was higher for the cases with invasion (56% versus 10%).

CONCLUSIONS.—

Tumoral intraductal neoplasms of the bile ducts, similar to their counterparts in the pancreas, are morphologically and genetically heterogeneous.

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.

Biliary Tract Cancer: Molecular Biology of Precursor Lesions

Biliary tract cancer is a devastating malignancy of the bile ducts and gallbladder with a dismal prognosis. The study of precancerous lesions has received considerable attention and led to a histopathological classification which, in some respects, remains an evolving field. Consequently, increasing efforts have been devoted to characterizing the molecular pathogenesis of the precursor lesions, with the aim of better understanding the mechanisms of tumor progression, and with the ultimate goal of meeting the challenges of early diagnosis and treatment. This review delves into the molecular mechanisms that initiate and promote the development of precursor lesions of intra- and extrahepatic cholangiocarcinoma and of gallbladder carcinoma. It addresses the genomic, epigenomic, and transcriptomic landscape of these precursors and provides an overview of animal and organoid models used to study them. In conclusion, this review summarizes the known molecular features of precancerous lesions in biliary tract cancer and highlights our fragmentary knowledge of the molecular pathogenesis of tumor initiation.

Intraductal papillary neoplasm of the bile duct: The new frontier of biliary pathology

Intraductal papillary neoplasms of the bile duct (IPNBs) represent a rare variant of biliary tumors characterized by a papillary growth within the bile duct lumen. Since their first description in 2001, several classifications have been proposed, mainly based on histopathological, radiological and clinical features, although no specific guidelines addressing their management have been developed. Bile duct neoplasms generally develop through a multistep process, involving different precursor pathways, ranging from the initial lesion, detectable only microscopically, i.e. biliary intraepithelial neoplasia, to the distinctive grades of IPNB until the final stage represented by invasive cholangiocarcinoma. Complex and advanced investigations, mainly relying on magnetic resonance imaging (MRI) and cholangioscopy, are required to reach a correct diagnosis and to define an adequate bile duct mapping, which supports proper treatment. The recently introduced subclassifications of types 1 and 2 highlight the histopathological and clinical aspects of IPNB, as well as their natural evolution with a particular focus on prognosis and survival. Aggressive surgical resection, including hepatectomy, pancreaticoduodenectomy or both, represents the treatment of choice, yielding optimal results in terms of survival, although several endoscopic approaches have been described. IPNBs are newly recognized preinvasive neoplasms of the bile duct with high malignant potential. The novel subclassification of types 1 and 2 defines the histological and clinical aspects, prognosis and survival. Diagnosis is mainly based on MRI and cholangioscopy. Surgical resection represents the mainstay of treatment, although endoscopic resection is currently applied to nonsurgically fit patients. New frontiers in genetic research have identified the processes underlying the carcinogenesis of IPNB, to identify targeted therapies.

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.

Molecular comparison of concurrent components of high-grade dysplasia, adenocarcinoma, and sarcomatoid carcinoma in a case of sarcomatoid carcinoma of the gallbladder

Detailed genetic and immunohistochemical features of a sarcomatoid carcinoma of the gallbladder were reported. Studied was a resected gallbladder tumor involving the transverse colon, which was consisted of 3 histopathological neoplastic components, i.e., high-grade dysplasia, adenocarcinoma, and sarcomatoid carcinoma. The targeted amplicon sequencing showed somatic mutations in TP53 (p.S90fs) and ARID1A (c.4993 + 1G > T) in all of the 3 components. Copy numbers of CDKN2A and SMAD4 were decreased in the adenocarcinoma and the sarcomatoid component. Immunohistochemistry showed loss of expression of p53 and ARID1A in all components. p16 expression was lost in the adenocarcinoma and the sarcomatoid component, while SMAD4 expression was lost only in the latter. These results suggest that this sarcomatoid carcinoma may have developed by progression from high-grade dysplasia via adenocarcinoma with sequential accumulation of molecular aberrations involving p53, ARID1A, p16, and SMAD4. This information should serve to understand the molecular mechanism of this very intractable tumor.

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.

Serine/Threonine Kinase 11 Plays a Canonical Role in Malignant Progression of KRAS -Mutant and GNAS -Wild-Type Intraductal Papillary Mucinous Neoplasms of the Pancreas

OBJECTIVE

We aimed to elucidate the clinicopathobiological significance of Serine/Threonine Kinase 11 (STK11) in pancreatic intraductal papillary mucinous neoplasms (IPMNs).

BACKGROUND

STK11 is a tumor suppressor involved in certain IPMNs; however, its significance is not well known.

METHODS

In 184 IPMNs without Peutz-Jeghers syndrome, we analyzed expression of STK11 and phosphorylated-AMPKa in all cases, and p16, p53, SMAD4, and β-catenin in 140 cases by immunohistochemistry; and we analyzed mutations in 37 genes, including whole coding exons of STK11, CDKN2A, TP53, and SMAD4, and hotspots of KRAS, BRAF, and GNAS in 64 cases by targeted sequencing. KRAS and GNAS were additionally analyzed in 86 STK11-normal IPMNs using digital-PCR.

RESULTS

Consistent loss or reduction of STK11 expression was observed in 26 of 184 (14%) IPMNs. These STK11-aberrant IPMNs were 17 of 45 (38%) pancreatobiliary, 8 of 27 (30%) oncocytic, 1 of 54 (2%) gastric, and 0 of 58 (0%) intestinal subtypes ( P = 8.5E-11), and 20 of 66 (30%) invasive, 6 of 74 (8%) high-grade, and 0 of 44 (0%) low-grade ( P = 3.9E-06). Sixteen somatic STK11 mutations (5 frameshift, 6 nonsense, 1 splicing, and 4 missense) were detected in 15/26 STK11-aberrant IPMNs ( P = 4.1E-06). All STK11-aberrantIPMNs were GNAS -wild-type and 96% of them were KRAS or BRAF -mutant.Morphologically, STK11-aberrant IPMNs presented "fern-like" arborizing papillae with thin fibrovascular core. Phosphorylated-AMPKa was down-regulated in STK11-aberrant IPMNs (92%, P = 6.8E-11). Patients with STK11-aberrant IPMNs showed poorer survival than patients with STK11-normal IPMNs ( P = 3.6E-04 overall; P = 6.1E-04 disease-free).

CONCLUSION

STK11 may play a canonical role in malignant progression and poor survival of patients with IPMNs. Aberrant STK11-driven phosphorylated AMPK downregulation may provide therapeutic opportunities with mTOR inhibitors/AMPK activators.

Development of intraductal papillary neoplasm of the bile duct in patients with occupational cholangiocarcinoma

This study aimed to investigate the clinicopathological findings of intraductal papillary neoplasm of the bile duct (IPNB) in patients with occupational cholangiocarcinoma caused by exposure to 1,2-dichloropropane and/or dichloromethane to elucidate the development of IPNB to cholangiocarcinoma. The clinicopathological findings of 17 IPNB lesions according to the size (1.5-20 mm in diameter) and their comparison between type 1 (n = 9) and type 2 IPNBs (n = 8) were investigated. An IPNB of <5 mm in size was classified as micro IPNB (n = 7), while those ≥5 mm in size were classified as ordinary IPNB (n = 10). Both types 1 and 2 IPNBs were observed in micro IPNB, and their proportions were not different between micro and ordinary IPNBs. The clinicopathological characteristics of types 1 and 2 IPNBs were fundamentally similar to those previously reported. IPNB with invasive carcinoma was only found in ordinary IPNB although the proportions of low-grade and high-grade epithelium were not different between micro IPNB and ordinary IPNB. All IPNB exhibited γH2AX and S100P, indicating the occurrence of DNA injury and malignant transformation in micro and ordinary IPNBs. These results indicate that the carcinogens may induce micro IPNB with types 1 or 2 at the initiation and then develop ordinary IPNB with types 1 or 2, subsequently, progressing to IPNB with invasive carcinoma in patients with occupational cholangiocarcinoma.

Risk Assessment and Cholangiocarcinoma: Diagnostic Management and Artificial Intelligence

Intrahepatic cholangiocarcinoma (iCCA) is the second most common primary liver tumor, with a median survival of only 13 months. Surgical resection remains the only curative therapy; however, at first detection, only one-third of patients are at an early enough stage for this approach to be effective, thus rendering early diagnosis as an efficient approach to improving survival. Therefore, the identification of higher-risk patients, whose risk is correlated with genetic and pre-cancerous conditions, and the employment of non-invasive-screening modalities would be appropriate. For several at-risk patients, such as those suffering from primary sclerosing cholangitis or fibropolycystic liver disease, the use of periodic (6-12 months) imaging of the liver by ultrasound (US), magnetic Resonance Imaging (MRI)/cholangiopancreatography (MRCP), or computed tomography (CT) in association with serum CA19-9 measurement has been proposed. For liver cirrhosis patients, it has been proposed that at-risk iCCA patients are monitored in a similar fashion to at-risk HCC patients. The possibility of using Artificial Intelligence models to evaluate higher-risk patients could favor the diagnosis of these entities, although more data are needed to support the practical utility of these applications in the field of screening. For these reasons, it would be appropriate to develop screening programs in the research protocols setting. In fact, the success of these programs reauires patient compliance and multidisciplinary cooperation.

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.

Cholangiocarcinoma: Molecular Abnormalities and Cells of Origin

Cholangiocarcinomas (CCAs) are a group of heterogeneous epithelial malignancies that can originate at the level of any location of the biliary tree. These tumors are relatively rare but associated with a high rate of mortality. CCAs are morphologically and molecularly heterogeneous and for their location can be distinguished as intracellular and extracellular, subdivided into perihilar and distal. Recent epidemiological, molecular, and cellular studies have supported that the consistent heterogeneity observed for CCAs may result from the convergence of various key elements mainly represented by risk factors, heterogeneity of the associated molecular abnormalities at genetic and epigenetic levels and by different potential cells of origin. These studies have consistently contributed to better defining the pathogenesis of CCAs and to identify in some instances new therapeutic targets. Although the therapeutic progress were still limited, these observations suggest that a better understanding of the molecular mechanisms underlying CCA in the future will help to develop more efficacious treatment strategies.

Intraductal oncocytic papillary neoplasm arising in Peutz-Jeghers Syndrome bile duct: a unique case report

BACKGROUND

Peutz-Jeghers syndrome (PJS) is a rare, autosomal dominant disorder caused by germline mutations of STK11/LKB1, with an increased risk of tumors at multiple sites. Intraductal oncocytic papillary neoplasm (IOPN) is a unique subtype of intraductal papillary neoplasm of the bile duct (IPNB) defined by a premalignant neoplasm with intraductal papillary or villous growth of biliary-type epithelium. IOPN has a distinct mutation profile compared with both IPNB and intraductal papillary mucinous neoplasm (IPMN).

CASE PRESENTATION

We herein describe the case of a 44-year-old woman who presented as polyps in the intestinal lumen of sigmoid colon and a 3.1 × 2.1 cm mass in the left lobe of liver. Gross feature revealed a cystic papillary mass and the neoplasm had a clear boundary with the surrounding liver tissue. Histology revealed complex papillary structures, a small amount of fine fibrovascular cores and immunohistochemistry showed extensive positive for MUC5AC, MUC6, CD117. Therefore, histological and immunohistochemical examination of the liver tumor suggested the diagnosis of IOPN. Next-generation sequencing (NGS) revealed other than STK11 germline mutation, the tumor also harbors GNAS somatic mutation at codon 478 and EGFR amplification.

CONCLUSION

To our knowledge, this is the first report of IOPN arising in PJS. This case enlarges the spectrum of PJS related tumors and genetic rearrangements in IOPN.

Comparison of the Malignant Predictors in Intrahepatic and Extrahepatic Intraductal Papillary Neoplasm of the Bile Duct

Background: Intraductal papillary neoplasm of the bile duct (IPNB) is a precancerous lesion of cholangiocarcinoma, for which surgical resection is the most effective treatment. We evaluated the predictors of malignancy in IPNB according to anatomical location and the prognosis without surgery. Methods: A total of 196 IPNB patients who underwent pathologic confirmation by surgical resection or endoscopic retrograde cholangiography or percutaneous transhepatic cholangioscopic biopsy were included. Clinicopathological findings of IPNB with invasive carcinoma or mucosal dysplasia were analyzed according to anatomical location. Results: Of the 116 patients with intrahepatic IPNB (I-IPNB) and 80 patients with extrahepatic IPNB (E-IPNB), 62 (53.4%) and 61 (76.3%) were diagnosed with invasive carcinoma, respectively. Multivariate analysis revealed that mural nodule > 12 mm (p = 0.043) in I-IPNB and enhancement of mural nodule (p = 0.044) in E-IPNB were predictive factors for malignancy. For pathologic discrepancy before and after surgery, IPNB has a 71.2% sensitivity and 82.3% specificity. In the non-surgical IPNB group, composed of nine I-IPNB and seven E-IPNB patients, 43.7% progressed to IPNB with invasive carcinoma within 876 days. Conclusions: E-IPNB has a higher rate of malignancy than I-IPNB. The predictive factor for malignancy is mural nodule > 12 mm in I-IPNB and mural nodule enhancement in E-IPNB.

Up-to-Date Pathologic Classification and Molecular Characteristics of Intrahepatic Cholangiocarcinoma

Intrahepatic cholangiocarcinoma (iCCA) is an aggressive primary liver malignancy with an increasing incidence worldwide. Recently, histopathologic classification of small duct type and large duct type iCCA has been introduced. Both these types of tumors exhibit differences in clinicopathological features, mutational profiles, and prognosis. Small duct type iCCA is composed of non-mucin-producing cuboidal cells, whereas large duct type iCCA is composed of mucin-producing columnar cells, reflecting different cells of origin. Large duct type iCCA shows more invasive growth and poorer prognosis than small duct type iCCA. The background liver of small duct type iCCA often shows chronic liver disease related to hepatitis B or C viral infection, or alcoholic or non-alcoholic fatty liver disease/steatohepatitis, in contrast to large duct type iCCA that is often related to hepatolithiasis and liver fluke infection. Cholangiolocarcinoma is a variant of small duct type iCCA composed of naïve-looking cuboidal cells forming cords or ductule-like structures, and shows better prognosis than the conventional small duct type. Fibrous tumor stroma, one of the characteristic features of iCCA, contains activated fibroblasts intermixed with innate and adaptive immune cells. The types of stroma (mature versus immature) are related to tumor behavior and prognosis. Low tumor-infiltrating lymphocyte density, KRAS alteration, and chromosomal instability are related to immune-suppressive tumor microenvironments with resistance to programmed death 1/ programmed death ligand 1 blockade. Data from recent large-scale exome analyses have revealed the heterogeneity in the molecular profiles of iCCA, showing that small duct type iCCA exhibit frequent BAP1, IDH1/2 hotspot mutations and FGFR2 fusion, in contrast to frequent mutations in KRAS, TP53, and SMAD4 observed in large duct type iCCA. Multi-omics analyses have proposed several molecular classifications of iCCA, including inflammation class and proliferation class. The inflammation class is enriched in inflammatory signaling pathways and expression of cytokines, while the proliferation class has activated oncogenic growth signaling pathways. Diverse pathologic features of iCCA and its associated multi-omics characteristics are currently under active investigation, thereby providing insights into precision therapeutics for patients with iCCA. This review provides the latest knowledge on the histopathologic classification of iCCA and its associated molecular features, ranging from tumor microenvironment to genomic and transcriptomic research.

Multigene Panel Sequencing Reveals Cancer-Specific and Common Somatic Mutations in Colorectal Cancer Patients: An Egyptian Experience

This study aims at identifying common pathogenic somatic mutations at different stages of colorectal carcinogenesis in Egyptian patients. Our cohort included colonoscopic biopsies collected from 120 patients: 20 biopsies from patients with inflammatory bowel disease, 38 from colonic polyp patients, and 62 from patients with colorectal cancer. On top of this, the cohort included 20 biopsies from patients with non-specific mild to moderated colitis. Targeted DNA sequencing using a customized gene panel of 96 colorectal related genes running on the Ion Torrent NGS technology was used to process the samples. Our results revealed that 69% of all cases harbored at least one somatic mutation. Fifty-seven genes were found to carry 232 somatic non-synonymous variants. The most frequently pathogenic somatic mutations were localized in TP53, APC, KRAS, and PIK3CA. In total, 16 somatic mutations were detected in the CRC group and in either the IBD or CP group. In addition, our data showed that 51% of total somatic variants were CRC-specific variants. The average number of CRC-specific variants per sample is 2.4. The top genes carrying CRC-specific mutations are APC, TP53, PIK3CA, FBXW7, ATM, and SMAD4. It seems obvious that TP53 and APC genes were the most affected genes with somatic mutations in all groups. Of interest, 85% and 28% of the APC and TP53 deleterious somatic mutations were located in Exon 14 and Exon 3, respectively. Besides, 37% and 28% of the total somatic mutations identified in APC and TP53 were CRC-specific variants, respectively. Moreover, we identified that, in 29 somatic mutations in 21 genes, their association with CRC patients was unprecedented. Ten detected variants were likely to be novel: six in PIK3CA and four variants in FBXW7. The detected P53, Wnt/βcatenin, Angiogenesis, EGFR, TGF-β and Interleukin signaling pathways were the most altered pathways in 22%, 16%, 12%, 10%, 9% and 9% of the CRC patients, respectively. These results would contribute to a better understanding of the colorectal cancer and in introducing personalized therapies for Egyptian CRC patients.

Pathological, molecular, and clinical characteristics of cholangiocarcinoma: A comprehensive review

Cholangiocarcinomas are a heterogeneous group of highly aggressive cancers that may arise anywhere within the biliary tree. There is a wide geographical variation with regards to its incidence, and risk-factor associations which may include liver fluke infection, primary sclerosing cholangitis, and hepatolithiasis amongst others. These tumours are classified into intrahepatic, perihilar and distal based on their anatomical location. Morphologically, intrahepatic cholangiocarcinomas are further sub-classified into small and large duct variants. Perihilar and distal cholangiocarcinomas are usually mucin-producing tubular adenocarcinomas. Cholangiocarcinomas develop through a multistep carcinogenesis and are preceded by dysplastic and in situ lesions. While clinical characteristics and management of these tumours have been extensively elucidated in literature, their ultra-structure and tumour biology remain relatively unknown. This review focuses on the current knowledge of pathological characteristics, molecular alterations of cholangiocarcinoma, and its precursor lesions (including biliary intraepithelial neoplasia, intraductal papillary neoplasms of the bile duct, intraductal tubulopapillary neoplasms and mucinous cystic neoplasm).

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.

Current challenges to underpinning the genetic basis for cholangiocarcinoma

AREAS COVERED

This review provides an overview regarding the current scenario and knowledge of the CCA genomic landscape and the potentially actionable molecular aberrations in each CCA subtype.

EXPERT OPINION

The establishment and advances of high-throughput methodologies applied to genetic and epigenetic profiling are changing many cancer types' therapeutic landscape , including CCA.The large body of data generated must be interpreted appropriately and eventually implemented in clinical practice. The following advancements toward precision medicine in CCA management will require designing better clinical trials with improved methods to stratify biliary tumor patients.

Pathological characterization of intracholecystic papillary neoplasm: A recently proposed preinvasive neoplasm of gallbladder

Intracholecystic papillary neoplasm (ICPN) is a recently proposed gallbladder neoplasm. Its prevalence and pathologies remain to be clarified. A total of 38 ICPN cases (28 ICPNs identified among 1904 cholecystectomies (1.5%) and in 100 surgically resected primary gallbladder neoplasms (28%) in Fukui Prefecture Saiseikai Hospital, Japan, and other 10 ICPNs) were examined pathologically and immunohistochemically. They were composed of 21 males and 17 females with a mean age of 75 years old, and presented intraluminal growth of papillary lesions with fine fibrovascular stalks. ICPNs were relatively frequent in the fundus (n = 11) and body (n = 9). Grossly, the conglomerated sessile type (n = 30) was more frequent than the isolated polypoid type (n = 8). All cases were classified as high-grade dysplasia, and they were further divided into 22 cases presenting irregular structures and 16 cases presenting regular structures. The former showed frequent complicated lesions and stromal invasion (54.5%) compared to the latter (12.5%). Twenty-four cases showed predominantly either of four subtypes (11 gastric, 7 intestinal, 4 biliary and 2 oncocytic subtype), while the remaining14 cases showed mixture of more than two subtypes. In conclusion, ICPN presented unique preinvasive neoplasm with characteristic histopathologies. Irregular histologies and complicated lesions of ICPN were related to stromal invasion.

Inhibition of FGF10-ERK signal activation suppresses intraductal papillary neoplasm of the bile duct and its associated carcinomas

Evidence regarding intraductal papillary neoplasm of the bile duct (IPNB) as a type of precancerous lesion of cholangiocarcinoma is limited. Moreover, a reproducible in vivo model is lacking, and IPNB pathogenesis remains unclear. Here, we use a doxycycline-inducible tetracycline (Tet)-on mice model to control fibroblast growth factor 10 (FGF10) expression, which regulates branching and tubule formation. FGF10-induced IPNB mimics the multifocal and divergent human IPNB phenotypes via the FGF10-FGF receptor 2 (FGFR2)-RAS-extracellular-signal-regulated kinase (ERK) signaling pathway. A paracrine/autocrine growth factor is sufficient to initiate and maintain IPNB originating from the peribiliary glands, including biliary stem/progenitor cells. With Kras^G12D, p53, or p16 mutations or both, Fgf10-induced IPNB shows stepwise carcinogenesis, causing associated invasive carcinoma. Fgf10-induced papillary changes and progression are suppressed by the inhibition of the FGF10-FGFR2-RAS-ERK signaling pathway, demonstrating that the signal is a therapeutic target for IPNB and associated carcinoma.

Reappraisal of pathological features of intraductal papillary neoplasm of bile duct with respect to the type 1 and 2 subclassifications

The pathological spectrum of intraductal papillary neoplasm of bile duct (IPNB) remains to be clarified. A total of 186 IPNBs were pathologically examined using the type 1 and 2 subclassifications proposed by Japanese and Korean biliary pathologists incorporating a two-tiered grading system (low-grade and high-grade dysplasia), with reference to four subtypes (intestinal [i], gastric [g], pancreatobiliary [pb], and concocytic [o] subtype). IPNBs were classifiable into type 1 composed of low-grade dysplasia and 'high-grade dysplasia with regular structures' (69 IPNBs), and type 2 of 'high grade dysplasia with irregular structures and complicated lesions' (117 IPNBs). Type 1 was more common in the intrahepatic bile duct (78%), whereas type 2 was frequently located in the extrahepatic bile duct (58%). Mucin hypersecretion was more common in type 1 (61%) than in type 2 (37%). IPNBs were classifiable into the four subtypes: 86 iPNBs, 40 gIPNBs, 31 pbIPNBs, and 29 oIPNBs. The four subtypes were histologically evaluable with reference to the type 1 and 2 subclassifications. iIPNB and pbIPNBs were frequently classified as type 2, whereas types 1 and 2 were observed at similar rates in gIPNB and oIPNB. Stromal invasion was almost absent in type 1, irrespective of subtype, but was found in 66 of 117 type 2 IPNBs (P < .01), and postoperative outcome was favorable in IPNBs without invasion compared with IPNBs with invasion (P < .05). The type 1 and 2 subclassifications with reference to the four subtypes may provide useful information for understanding IPNB.

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 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.