Intraductal papillary neoplasm of the bile ducts: description of MRI and added value of diffusion-weighted MRI. ACTA ACUST UNITED AC. 2013;38:1082-1090. [PMID: 23508835 DOI: 10.1007/s00261-013-9989-4]

Intraductal papillary neoplasm of the bile duct: diagnostic value of MRI features in differentiating pathologic subclassifications-type 1 versus type 2

OBJECTIVES

To identify MRI features for differentiating type 2 from type 1 intraductal papillary neoplasms of bile duct (IPNB) and assessing malignant potential of IPNB.

METHODS

This retrospective study included 60 patients with surgically proven IPNB who had undergone preoperative MRI between January 2007 and December 2020. All surgical specimens were reviewed retrospectively to classify types 1 and 2 IPNBs and assess tumor grade. Significant MRI features for differentiating type 2 (n = 40) from type 1 IPNB (n = 20); and for IPNB with an associated invasive carcinoma (n = 43) from intraepithelial neoplasia (n = 17) were determined using logistic regression analysis.

RESULTS

An associated invasive carcinoma was more frequently found in type 2 than in type 1 IPNB (85.0% [34/40] vs. 45.0% [9/20], p = 0.003). At univariable analysis, MRI features including extrahepatic location, no dilatation of tumor-bearing segment of bile duct, isolated upstream bile duct dilatation, and single lesion were associated with type 2 IPNB (all p ≤ 0.012). At multivariable analysis, significant MRI findings for differentiating type 2 from type 1 IPNB were extrahepatic location and no dilatation of tumor-bearing segment of bile duct (odds ratio [OR], 7.24 and 46.40, respectively). At univariable and multivariable analysis, tumor size ≥ 2.5 cm (OR, 8.45), bile duct wall thickening (OR, 4.82), and irregular polypoid or nodular tumor shape (OR, 6.44) were significant MRI features for differentiating IPNB with an associated invasive carcinoma from IPNB with intraepithelial neoplasia.

CONCLUSION

MRI with MR cholangiopancreatography may be helpful in differentiating type 2 IPNB from type 1 IPNB and assessing malignant potential of IPNB.

CLINICAL RELEVANCE STATEMENT

Preoperative MRI with MR cholangiopancreatography may be helpful in differentiating type 2 intraductal papillary neoplasms of bile duct (IPNB) from type 1 IPNB and assessing malignant potential of IPNB.

KEY POINTS

• In terms of tumor grade, the incidence of invasive carcinoma was significantly higher in type 2 intraductal papillary neoplasm of the bile duct (IPNB) than in type 1 IPNB. • At MRI, extrahepatic location and no dilatation of tumor-bearing segment are significant features for differentiating type 2 IPNBs from type 1 IPNBs. • At MRI, large tumor size, bile duct wall thickening, and irregular polypoid or nodular tumor shape are significant features for differentiating IPNB with an associated invasive carcinoma from IPNB with intraepithelial neoplasia.

Biliary Duct Dilatation: AJR Expert Panel Narrative Review

Biliary duct dilatation is a common incidental finding in practice, but it is unlikely to indicate biliary obstruction in the absence of clinical symptoms or elevated levels on liver function tests (LFTs). However, the clinical presentation may be nonspecific, and LFTs may either be unavailable or difficult to interpret. The goal of this AJR Expert Panel Narrative Review is to highlight a series of topics fundamental to the management of biliary duct dilatation, providing consensus recommendations in a question-and-answer format. We start by covering a basic approach to interpreting LFT results, the strengths and weaknesses of the biliary imaging modalities, and how and where to measure the extrahepatic bile duct. Next, we define the criteria for biliary duct dilatation, including patients with prior cholecystectomy and advanced age, and discuss when and whether biliary duct dilatation can be attributed to papillary stenosis or sphincter of Oddi dysfunction. Subsequently, we discuss two conditions in which the duct is pathologically dilated but not obstructed: congenital cystic dilatation (i.e., choledochal cyst) and intraductal papillary neoplasm of the bile duct. Finally, we provide guidance regarding when to recommend obtaining additional imaging or testing, such as endoscopic ultrasound or ERCP, and include a discussion of future directions in biliary imaging.

MRI features of intraductal papillary mucinous neoplasm of the bile ducts, "The myth about the cyst": A systematic review

Rationale and objectives

Intraductal papillary mucinous neoplasm of the bile ducts (IPMN-B) is a true pre-cancerous lesion, which shares common features with pancreatic IPMN (IPMN-P). While IPMN-P is a well described entity for which guidelines were formulated and revised, IPMN-B is a poorly described entity.We carried out a systematic review to evaluate the existing literature, emphasizing the role of MRI in IPMN-B depiction.

Materials and methods

PubMed database was used to identify original studies and case series that reported MR Imaging features of IPMN-B. The search keywords were "IPMN OR intraductal papillary mucinous neoplasm OR IPNB OR intraductal papillary neoplasm of the bile duct AND Biliary OR biliary cancer OR hepatic cystic lesions". Risk of bias and applicability were evaluated using the QUADAS-2 tool.

Results

884 Records were Identified through database searching. 12 studies satisfied the inclusion criteria, resulting in MR features of 288 patients. All the studies were retrospective. Classic features of IPMN-B are under-described. Few studies note worrisome features, concerning for an underlying malignancy. 50 % of the studies had a high risk of bias and concerns regarding applicability.

Conclusions

The MRI features of IPMN-B are not well elaborated and need to be further studied. Worrisome features and guidelines regarding reporting the imaging findings should be established and published. Radiologists should be aware of IPMN-B, since malignancy diagnosis in an early stage will yield improved prognosis.

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.

Imaging of Hepatobiliary Cancer

The liver and biliary tree are common sites of primary and secondary malignancies. MRI followed by CT is the mainstay for the imaging characterization of these malignancies with the dynamically acquired contrast enhanced phases being the most important for diagnosis. The liver imaging reporting and data system classification provides a useful framework for reporting lesions in patents with underlying cirrhosis or who are at high risk for developing hepatocellular carcinoma. Detection of metastases is improved with the use of liver specific MRI contrast agents and diffusion weighted sequences. Aside from hepatocellular carcinoma, which is often diagnosed noninvasively, other primary hepatobiliary tumors may require biopsy for definite diagnosis, especially when presenting with nonclassic imaging findings. In this review, we examine the imaging findings of common and less common hepatobiliary tumors.

Intraductal papillary mucinous neoplasm of the intrahepatic bile duct: a review of literature and a rare case report

Background

Intraductal papillary neoplasm of the bile duct is a rare variant of bile duct tumors, which is characterized by papillary or villous growth inside the bile duct. Having papillary and mucinous features such as those found in pancreatic intraductal papillary mucinous neoplasm (IPMN) is extremely rare. We report a rare case of intraductal papillary mucinous neoplasm of the intrahepatic bile duct.

Case report

A 65-year-old male Caucasian with multiple comorbidities presented to the emergency room with moderate constant pain at the right upper quadrant (RUQ) abdomen for the last several hours. On physical examination, he was found to have normal vital signs, with icteric sclera and pain on deep palpation at the RUQ region. His laboratory results were significant for jaundice, elevated liver function tests and creatinine, hyperglycemia, and leukocytosis. Multiple imaging studies revealed a 5 cm heterogeneous mass in the left hepatic lobe that demonstrated areas of internal enhancement, mild gall bladder wall edema, dilated gall bladder with mild sludge, and 9 mm common bile duct (CBD) dilatation without evidence of choledocholithiasis. He underwent a CT-guided biopsy of this mass, which revealed intrahepatic papillary mucinous neoplasm. This case was discussed at the hepatobiliary multidisciplinary conference, and the patient underwent an uneventful robotic left partial liver resection, cholecystectomy, and lymphadenectomy.

Conclusion

IPMN of the biliary tract may represent a carcinogenesis pathway different from that of CBD carcinoma arising from flat dysplasia. Complete surgical resection should be performed whenever possible because of its significant risk of harboring invasive carcinoma.

Intraductal papillary neoplasm of the bile duct presenting with hepatogastric fistula: a case report and literature review

Intraductal papillary neoplasm of the bile duct (IPNB) is an uncommon entity characterized by papillary growth within the bile duct lumen. IPNB is regarded as a biliary counterpart of intraductal papillary mucinous neoplasm of the pancreas, which sometimes complicates with fistula formation to adjacent organs, mainly due to high-pressure related erosion from mucin-filled ducts. However, fistula formation from IPNB is quite rare. Here we report a case of IPNB complicated with hepatogastric fistula. Abdominal computed tomography (CT) and magnetic resonance imaging (MRI) revealed disproportional dilatation of left intrahepatic duct with intraluminal soft tissue nodules and fistulous connections to gastric high body. Endoscopy revealed ulcers with two fistulous orifices at upper gastric body. The patient underwent left hepatectomy with gastric wedge resection. Histopathology examination revealed IPNB with invasive cholangiocarcinoma, directly invading to gastric wall leading to hepatogastric fistula. In summary, we have presented the clinical, imaging and pathological findings, along with a comprehensive review of relevant literature, in order to enhance the understanding of this rare condition.

Hepatobiliary mucinous cystic neoplasms and mimics

This review will provide an overview of hepatobiliary mucinous cystic neoplasms and their mimics such as complex appearing benign cysts, intraductal papillary neoplasm of bile ducts, choledochal cysts, infectious cysts, and other cystic neoplasms. Preoperative imaging, particularly abdominal MRI with MRCP, plays a key role in differentiating these entities which differ widely in management. Familiarity with the differentiating imaging features of mucinous cystic neoplasms and their mimics allows radiologists to provide management-guiding reports.

Imaging Features of Premalignant Biliary Lesions and Predisposing Conditions with Pathologic Correlation

Biliary malignancies include those arising from the intrahepatic and extrahepatic bile ducts as well as the gallbladder and hepatopancreatic ampulla of Vater. The majority of intrahepatic and extrahepatic malignancies are cholangiocarcinomas (CCAs). They arise owing to a complex interplay between the patient-specific genetic background and multiple risk factors and may occur in the liver (intrahepatic CCA), hilum (perihilar CCA), or extrahepatic bile ducts (distal CCA). Biliary-type adenocarcinoma constitutes the most common histologic type of ampullary and gallbladder malignancies. Its prognosis is poor and surgical resection is considered curative, so early detection is key, with multimodality imaging playing a central role in making the diagnosis. There are several risk factors for biliary malignancy as well as predisposing conditions that increase the risk; this review highlights the pertinent imaging features of these entities with histopathologic correlation. The predisposing factors are broken down into three major categories: (a) congenital malformations such as choledochal cyst and pancreaticobiliary maljunction; (b) infectious or inflammatory conditions such as parasitic infections, hepatolithiasis, primary sclerosing cholangitis, and porcelain gallbladder; and (c) preinvasive epithelial neoplasms such as biliary intraepithelial neoplasm, intraductal papillary neoplasm of the bile duct, intra-ampullary papillary tubular neoplasm, and intracholecystic papillary neoplasm of the gallbladder. Recognizing the baseline features of these premalignant biliary entities and changes in their appearance over time that indicate the advent of malignancy in high-risk patients can lead to early diagnosis and potentially curative management. An invited commentary by Volpacchio is available online. Online supplemental material is available for this article. ^©RSNA, 2022.

Spectrum of MRI Features of Mucin-producing Neoplasms in the Abdomen and Pelvis

Mucin-producing neoplasms in the abdomen and pelvis are a distinct entity, separate from simple fluid-containing neoplasms and loculated fluid collections. Mucin is a thick gelatinous substance and-owing to its high water content-has imaging features that can be mistaken for those of simple fluid-containing neoplasms with multiple imaging modalities. However, mucin-producing neoplasms arise from specific organs in the abdomen and pelvis, with unique imaging appearances, knowledge of which is important to guide accurate diagnosis and management. With its large field of view and high soft-tissue resolution, MRI has advantages over other imaging modalities in characterizing these neoplasms. The authors focus on the spectrum of MRI features of such mucin-producing neoplasms and illustrate how-despite a varied organ origin-some of these neoplasms share similar MRI and histopathologic features, thereby helping narrow the differential diagnosis. One common finding in these tumors is that the presence of internal complexity and solid enhancing components increases as the degree of malignant transformation increases. Lack of internal complexity generally indicates benignity. These tumors have a varied range of prognosis; for example, a low-grade appendiceal mucinous neoplasm is indicative of a good prognosis, while a mucinous tumor of the rectum is known to manifest at an early age with aggressive behavior and poorer prognosis compared with its nonmucinous counterpart. Online supplemental material is available for this article. ^©RSNA, 2022.

Magnetic Resonance Diffusion-Weighted Imaging for Detecting Fundal Intracholecystic Papillary Neoplasm inside Rokitansky-Aschoff Sinuses: A Comparison of Two Cases and a Literature Review

Rokitansky-Aschoff sinuses (RAS) are a common imaging finding in gallbladder adenomyomatosis (ADM), often presenting as fundal cystic spaces. Intracholecystic papillary neoplasm (ICPN) is a relatively uncommon pre-invasive tumor of the gallbladder epithelium that rarely involves RAS mucosa. We compare two cases that showed similar fundal cystic spaces resembling RAS, in which Magnetic Resonance Diffusion-Weighted Imaging (MR-DWI) was valuable for detecting (or ruling out) an underlying malignant ICPN. Evidence from the literature overall supports the role of MR-DWI for detecting intracholecystic malignant tissue.

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.

Imaging of Intrahepatic Cholangiocarcinoma

Cholangiocarcinoma is the second most common primary hepatic malignancy and is a heterogeneous tumor of biliary epithelium. We discuss the risk factors, anatomic classification of cholangiocarcinoma (CC) as well as the different morphologic subtypes of CC. Imaging findings of CC on different modalities are described, focusing on intrahepatic CC. Recently recognized imaging features that carry prognostic significance, such as a worse prognosis in tumors that have more desmoplastic stroma, are detailed. Other benign and malignant entities that should be considered in the differential diagnosis of CC will also be discussed.

Intraductal papillary neoplasm of the bile duct - A comprehensive review

BACKGROUND

Intraductal papillary neoplasm of the bile ducts is a rare tumor type. Management decisions are currently based upon a small case series. The authors have large own experience with IPNB.

OBJECTIVE

The review aims at reporting on clinicopathological features of IPNB in order to provide guidance for management.

METHODS

We searched PubMed, Medline, Microsoft Academic and Embase databases to identify studies of relevance. The analysis of own experience was also included.

RESULTS

We analyzed 59 retrospective series and 25 cases from authors' clinical experience. The main sign was jaundice and cholangitis, 33% and 48%, respectively. CT's were performed in 63-76% and MR in 40-56%. Intraductal mass was found in 31-32% and duct dilatation in 27-30%. Endoscopic Retrograde Cholangio-Pancreatography (ERCP) was performed in 48-62%. IPNB with invasive carcinoma was found in 35.7-60% and IPNB with intraepithelial neoplasia in 36-60%. Histopathological confirmation before surgery was rare. The main treatment of IPNB is resection, in our material, both, hepatectomy and hepatectomy plus bile duct resections were performed in 40% of patients. The percentage of postoperative complications was 20%. The 5-year survival rate of all IPNB's patients was 53.6%; in patients with associated invasive carcinoma - 22.2% and without invasive carcinoma - 100% (p ​= ​0.001).

CONCLUSIONS

Early surgery is advisable for radiologically suspected IPNB. The results of treatment depend on histopathology. They are worse at intraductal invasive carcinoma than at neoplasm with neoplasia.

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.

Intraductal papillary neoplasm of bile duct: all rare in one

A 45-year-old woman was referred from Department of Dermatology to Surgery outpatient department with pruritus since 6 months and an episode of jaundice that lasted for 15 days about 6 months ago. She was referred with a contrast-enhanced MRI finding that showed a small lesion in the lower end of common bile duct. Endoscopy-guided biopsy was performed twice at our hospital, the second revealed low grade dysplasia. Consequently, she underwent pancreaticoduodenectomy. Intraoperatively, there were both vascular and biliary anatomical variations that were missed on preoperative images. On histopathological examination, it turned out to be a mixed variety of intraductal papillary neoplasm of bile duct (IPNB). As all findings were rare in one, hence, we present this case of IPNB that presented to us with variable clinical, radiological, surgical and pathological findings.

Peribiliary glands: development, dysfunction, related conditions and imaging findings

Peribiliary glands are minute structures that are distributed along the intrahepatic large bile ducts, extrahepatic bile duct, and cystic duct. These glands regulate many physiological functions, such as enzyme secretion. Pancreatic exocrine tissues and enzymes are often observed in peribiliary glands; thus, peribiliary glands are involved in enzyme secretion. As such, these glands can be affected by conditions such as IgG4-related sclerosing cholangitis based on commonalities with their pancreatic counterparts. Cystic changes in peribiliary glands can occur de novo, as part of a congenital syndrome, or secondary to insults such as alcoholic cirrhosis. Biliary tree stem/progenitor cells have recently been identified in peribiliary glands. These cells are involved in turnover and regeneration of biliary epithelia as well as in sclerosing reactions in some pathological conditions, such as primary sclerosing cholangitis and hepatolithiasis. Notably, hepatolithiasis is involved in mucin secretion by the peribiliary glands. Additionally, these cells are associated with the manifestation of several neoplasms, including intraductal papillary neoplasm, cystic micropapillary neoplasm, and cholangiocarcinoma. Normal peribiliary glands themselves are particularly small structures that cannot be recognized using any available imaging modalities; however, these glands are closely associated with several diseases, as mentioned above, which have typical imaging features. Therefore, knowledge of the basic pathophysiology of peribiliary glands is helpful for understanding biliary diseases associated with the peribiliary glands.

Early detection of intrahepatic cholangiocarcinoma

Cholangiocarcinoma (CC) is a malignant tumor which arises from the biliary epithelium and most cases represent adenocarcinoma. CC can be classified into intrahepatic CC (ICC), perihilar CC, and distal CC, based on the site of anatomic origin. The incidence of ICC is increasing in both Western and Eastern countries, while that of extrahepatic cholangiocarcinoma remains fairly stable. ICC infiltrates into adjacent nerves and lymphatic vessels, resulting in progressive disease with a poor prognosis; thus, early detection of ICC is critical for achieving better outcomes and providing better patient care. However, it is difficult for clinicians to detect an ICC, especially in its early stage. Different from hepatocellular carcinoma, the lack of surveillance system for the high-risk group of CC does not allow for a reliable screening examination. In this context, for early detection and diagnosis of ICC, radiologists need to know predisposing conditions that can lead to the development of ICC, such as chronic biliary or hepatic inflammation, primary sclerosing cholangitis, congenital biliary diseases, and other conditions. In this article, we discuss and illustrate the radiologic features of ICC with special attention to early disease stages and of predisposing conditions of ICC.

Intraductal papillary neoplasm of the bile duct: Assessment of invasive carcinoma and long-term outcomes using MRI

BACKGROUND & AIMS

Imaging characteristics for discriminating the malignant potential of intraductal papillary neoplasm of the bile duct (IPNB) still remain unclear. This study aimed to define the magnetic resonance (MR) imaging findings that help to differentiate IPNB with an associated invasive carcinoma from IPNB with intraepithelial neoplasia and to investigate their significance with respect to long-term outcomes in patients with surgically resected IPNB.

METHODS

This retrospective study included 120 patients with surgically resected IPNB who underwent preoperative MR imaging with MR cholangiography before surgery from January 2008 and December 2017 in two tertiary referral centers. Clinical and MR imaging features of IPNB with intraepithelial neoplasia (n = 34) and IPNB with an associated invasive carcinoma (n = 86) were compared. Regarding significant features for discriminating IPNB with or without an associated invasive carcinoma, recurrence-free survival (RFS) rates were evaluated.

RESULTS

Significant MR imaging findings for differentiating IPNB with an associated invasive carcinoma from IPNB with intraepithelial neoplasia were intraductal visible mass, tumor size ≥2.5 cm, multiplicity of the tumor, bile duct wall thickening, and adjacent organ invasion (all p ≤0.002). The 1-, 3-, and 5-year RFS rates for surgically resected IPNB were 93.8%, 79.1%, and 70.0%, respectively. RFS rates were significantly lower in patients with each significant MR imaging finding of IPNB with an associated invasive carcinoma than in those without significant MR imaging findings (all p ≤0.039).

CONCLUSIONS

MR imaging with MR cholangiography may be helpful in differentiating IPNB with an associated invasive carcinoma from IPNB with intraepithelial neoplasia. Significant MR imaging findings of IPNB with an associated invasive carcinoma have a negative impact on RFS.

LAY SUMMARY

Significant magnetic resonance imaging findings that differentiated between an intraductal papillary neoplasm of the bile duct (IPNB) with an associated invasive carcinoma and an IPNB with intraepithelial neoplasia were intraductal visible mass, tumor size ≥2.5 cm, multiplicity of the tumor, bile duct wall thickening, and adjacent organ invasion. Significant magnetic resonance imaging findings of invasive IPNB have a negative impact on recurrence-free survival.

Uncommon Intraluminal Tumors of the Gallbladder and Biliary Tract: Spectrum of Imaging Appearances

Intraluminal pathologic conditions of the bile ducts and gallbladder are common, most frequently consisting of calculi and adenocarcinoma. In recent years, intraductal papillary neoplasm of the bile ducts (IPN-B), which is analogous to intraductal papillary mucinous neoplasm of the pancreas, has been recognized as a distinct pathologic entity and a precursor lesion to adenocarcinoma of the bile ducts. Intraductal tubulopapillary neoplasm (ITPN) of the bile duct was subsequently described as a distinct pathologic entity. With increased awareness and advances in imaging techniques, these lesions are diagnosed with increased frequency at preoperative imaging. A similar neoplasm in the gallbladder is referred to as intracholecystic papillary neoplasm. These lesions are often diagnosed at a preinvasive stage and have a better prognosis than invasive cholangiocarcinoma when treated with curative resection, underscoring the importance of an accurate imaging diagnosis. The most common causes of polypoid lesions of the gallbladder are cholesterol polyps and adenomyomatosis. These lesions need to be differentiated from the less common but clinically important adenocarcinoma of the gallbladder. Imaging is crucial to identify polyps that are at high risk for malignancy so that the appropriate management choice between imaging follow-up and cholecystectomy can be made by the treating physicians. Other less common gallbladder tumors, such as gallbladder adenomas, lymphoma, and metastases to the gallbladder, can manifest as intraluminal tumors; and awareness of these lesions is also important. In this article, the recent literature is reviewed; and the imaging appearances, histopathologic findings, and management of uncommon intraluminal tumors of the bile ducts and gallbladder and their mimics are discussed. ^©RSNA, 2019.

Skewness of apparent diffusion coefficient (ADC) histogram helps predict the invasive potential of intraductal papillary neoplasms of the bile ducts (IPNBs)

OBJECTIVE

This retrospective study was to explore the value of whole lesion apparent diffusion coefficient (ADC) histogram in distinguishing invasive and noninvasive intraductal papillary neoplasms of the bile ducts (IPNBs).

METHOD AND MATERIALS

Fifty-two patients of IPNB underwent MRI at 1.5T with diffusion-weighted imaging (DWI, b = 500 s/mm²) before surgical resections. ADC histogram metrics were generated by using the software MR OncoTreat. The mean, standard deviation, median, skewness, kurtosis as well as the 10th, 25th, 75th, and 90th percentiles were compared between pathologically defined invasive (n = 35) and noninvasive (n = 17) IPNBs. Such conventional imaging characters as lesion location, bile duct wall dilation, and mural nodularity were also assessed. Multivariate regression analysis as well as receiver operating characteristics (ROC) analysis were then conducted to determine the predictive factors and to evaluate potential diagnostic performances.

RESULTS

The inter-operator reliability was good to excellent (ICC: 0.693-979). Mean median, kurtosis, and the 10th, 25th, 75th, 90th percentiles were all greater in noninvasive group than invasive ones (P: 0.00-002). Skewness was lower in noninvasive group than invasive ones (- 1.0 ± 0.6 vs. - 0.3 ± 0.6, P = 0.00). After multivariate regression, skewness (AUC = 0.822, 95%CI 0.70-0.91) and mural nodularity (accuracy = 0.808) were the only two independent factors in predicting invasive IPNBs. The diagnostic performance improved (AUC = 0.867, 95%CI 0.742-0.946) when combining skewness and mural nodularity, however, the difference did not reach statistical significance (P = 0.16).

CONCLUSION

The ADC histogram has capability of distinguishing invasive and noninvasive IPNBs, in which skewness was an independent predictive factor.

Intraductal Papillary Neoplasm of the Bile Duct: Clinical, Imaging, and Pathologic Features

OBJECTIVE

We outline the concept of intraductal papillary neoplasm of the bile duct (IPNB), discuss the morphologic features of IPNB and the differential diagnoses, and describe the radiologic approaches used in multidisciplinary management.

CONCLUSION

The concept of IPNB has been evolving. Because the imaging features of IPNB can be variable, different mimickers according to IPNB subtype can be considered. A multimodality approach is essential to obtain an optimal diagnosis and establish treatment plans.

Cholangiocarcinoma: classification, diagnosis, staging, imaging features, and management

Cholangiocarcinoma is a relatively uncommon malignant neoplasm with poor prognosis. The distinction between extrahepatic and intrahepatic subtypes is important as epidemiological features, biologic and pathologic characteristics, and clinical course are different for both entities. This review study focuses on the role imaging plays in the diagnosis, classification, staging, and post-treatment assessment of cholangiocarcinoma.

Cross-Sectional Imaging of Intrahepatic Cholangiocarcinoma: Development, Growth, Spread, and Prognosis

OBJECTIVE

Intrahepatic cholangiocarcinoma (ICC) is a malignant tumor that arises from the intrahepatic bile ducts. Although the pathologic and imaging features of ICC have been clearly identified, recent updates have addressed the pathologic classification and imaging features of ICC using new imaging techniques. First, a proposed new pathologic ICC subclassification includes perihilar large duct and peripheral small duct ICCs. Second, advanced MR-based imaging features of ICC, such as hepatobiliary phase imaging using hepatocytespecific contrast material and DWI, have recently been described. These imaging features are important when differentiating ICCs from hepatocellular carcinomas. Finally, some imaging features of ICC, such as prominent arterial enhancement or degree of delayed enhancement, exhibit potential as prognostic imaging biomarkers.

CONCLUSION

Comprehensive and updated knowledge of ICC is necessary for accurate diagnosis and could facilitate prediction of clinical outcomes for patients with ICC.

Uncommon liver tumors: Case report and literature review

BACKGROUND

Beside hepatocellular carcinoma, metastasis, and cholangiocarcinoma, the imaging findings of other relatively uncommon hepatic lesions are less discussed in the literature. Imaging diagnosis of these lesions is a daily challenge. In this article, we review the imaging characteristics of these neoplasms.

METHODS

From January 2003 to December 2014, 4746 patients underwent liver biopsy or hepatic surgical resection in our hospital. We reviewed the pathological database retrospectively. Imaging of these lesions was reviewed.

RESULTS

Imaging findings of uncommon hepatic lesions vary. We discuss the typical imaging characteristics with literature review. Clinical and pathological correlations are also described. Primary hepatic lymphoma consists only of 1% of the extranodal non-Hodgkin lymphoma, and is defined as the one involving only the liver and perihepatic lymph nodes within 6 months after diagnosis. Combined hepatocellular and cholangiocarcinoma (cHCC-CC) shares some overlapping imaging characteristics with both HCC and cholangiocarcinoma because of being an admixture of them. Angiosarcoma is the most common hepatic mesenchymal tumor and is hypervascular in nature. Inflammatory pseudotumor is often heterogeneous on ultrasonography and with enhanced septations and rims in the portovenous phase after contrast medium. Angiomyolipoma (AML) typically presents with macroscopic fat components with low signal on fat-saturated magnetic resonance imaging (MRI) and presence of drainage vessels. Intraductal papillary neoplasm of the bile duct (IPNB) is thought of as a counterpart to the pancreatic intraductal papillary mucinous neoplasm. Most of the IPNBs secrete mucin and cause disproportional dilatation of the bile ducts. Mucinous cystic neoplasm (MCN) contains proteinaceous and colloidal components without ductal communication and characterizes with hyperintensity on T1-weighted imaging. Other extremely rare lesions, including epithelioid hemangioendothelioma and inflammatory pseudotumor-like follicular dendritic cell sarcoma, are also discussed. Hepatoblastoma and mesenchymal hamartoma, mostly in children, are also briefly reviewed as well.

CONCLUSION

It is important for radiologists to be familiar with the typical imaging features of the uncommon hepatic neoplasms. If imaging findings are not typical or diagnostic, further biopsy is required.

Diffusion-weighted MR imaging of non-complicated hepatic cysts: Value of 3T computed diffusion-weighted imaging

Purpose

To investigate the utility of computed 3T diffusion-weighted imaging (c-DWI) for the diagnosis of non-complicated hepatic cysts with a focus on the T2 shine-through effect.

Materials and methods

In 50 patients with non-complicated hepatic cysts we acquired one set of DWIs (b-value 0 and 1000 s/mm²) at 1.5T, and two sets at 3T (b-value 0 and 1000 s/mm², TE 70 ms; b-value 0 and 600 s/mm², TE 60 ms). We defined the original DWIs acquired with b = 1000 s/mm² at 1.5T and 3T as “o-1.5T-1000” and “o-3T-1000”. c-DWIs were calculated with 3T DWI at b-values of 0 and 600 s/mm². c-DWI with b = 1000 and 1500 s/mm² were defined as “c-1000” and “c-1500”. Radiologists evaluated the signal intensity (SI) of the cysts using a 3-point score where 1 = not visible, 2 = discernible, and 3 = clearly visible. They calculated the contrast ratio (CR) between the cysts and the surrounding liver parenchyma on each DWIs and recorded the apparent diffusion coefficient (ADC) with a b-value = 0 and 1000 s/mm² on 1.5T- and 3T DWIs.

Results

Compared with o-1.5T-1000 DWI, the visual scores of all but the c-1500 DWIs were higher (p = 0.07 for c-1500- and p < 0.01 for the other DWIs). The CR at b = 1000 s/mm² was higher on o-3T-1000- than on o-1.5T-1000- (p < 0.01) but not higher than on c-1500 DWIs (p = 0.96). The CR at b = 0 s/mm² on 3T images with TE 70 ms was higher than on 1.5T images (p < 0.01). The ADC value was higher for 3T- than 1.5T images (p < 0.01).

Conclusions

Non-complicated hepatic cysts showed higher SI on o-3T-1000- than o-1.5T-1000 DWIs due to the T2-shine through effect. This high SI was suppressed on c-1500 DWIs.

Systematic Review and Meta-analysis of Current Experience in Treating IPNB: Clinical and Pathological Correlates

OBJECTIVE

To systematically review studies reporting clinicopathological features of intraductal papillary neoplasm of the bile duct (IPNB) to provide evidence-based guidance for management.

BACKGROUND

IPNB is a rare tumor type. Management decisions are currently based upon anecdotal evidence and small case series. To data, there has been no systematic review of IPNB literature.

METHODS

MEDLINE, EMBASE, and the Cochrane Database of Systematic Reviews were searched and data were extracted from relevant studies. Meta-analysis was used to pool study estimates. Evidence of association was determined by comparing pooled crude odds ratios (OR) derived from abstracted data.

RESULTS

Fifty-seven retrospective case series were included. At least 43% of 476 specimens contained invasive disease. Invasive tumors were found at significantly higher frequency in pancreaticobiliary than intestinal, gastric or oncocytic-type IPNB [pooled OR 2.5, 95% confidence interval (CI) 1.5-4.2, P < 0.001]. A significantly higher proportion of pancreaticobiliary tumors compared with intestinal tumors expressed MUC-1 [86.4% (95% CI 75.1%-94.7%) vs 13.2% (95% CI 4.6%-25.2%), respectively P < 0.001]. IPNB identified in centers from Asia were more likely to be intrahepatic and were less frequently invasive compared with those from Western centers. Pooled estimates of absolute survival after IPNB resection were 96% (95% CI 93%-99%) at 1 year, 79% (95% CI 69%-88%) at 3 years, and 65% (95% CI 46%-76%) at 5 years.

CONCLUSIONS

Early surgery is advisable for radiologically suspected IPNB as it is frequently invasive. The pathobiology of IPNB demonstrates geographic variation. Pancreaticobiliary IPNB expresses MUC1 and is more frequently associated with invasive disease than other IPNB subtypes.

"Biliary Diseases with Pancreatic Counterparts": Cross-sectional Imaging Findings

On the basis of the similarities in the histopathologic findings and the clinical-biologic behaviors of select biliary and pancreatic conditions, a new disease concept, "biliary diseases with pancreatic counterparts," has been proposed. Both nonneoplastic and neoplastic pathologic conditions of the biliary tract have their counterparts in the pancreas. Immunoglobulin G4 (IgG4)-related sclerosing cholangitis is the biliary manifestation of IgG4-related sclerosing disease, and type 1 autoimmune pancreatitis is its pancreatic counterpart. People with chronic alcoholism can develop peribiliary cysts and fibrosis as well as pancreatic fibrosis and chronic pancreatitis simultaneously. Pancreatic ductal adenocarcinoma, intraductal papillary mucinous neoplasm, and mucinous cystic neoplasm are considered pancreatic counterparts for the biliary neoplasms of extrahepatic cholangiocarcinoma, intraductal papillary neoplasm of the biliary tract, and hepatic mucinous cystic neoplasm, respectively. The anatomic proximity of the biliary tract and the pancreas, the nearly simultaneous development of both organs from the endoderm of the foregut, and the presence of pancreatic exocrine acini within the peribiliary glands surrounding the extrahepatic bile ducts are suggested as causative factors for these similarities. Interestingly, these diseases show "nearly" identical findings at cross-sectional imaging, an observation that further supports this new disease concept. New information obtained with regard to biliary diseases can be used for evaluation of pancreatic abnormalities, and vice versa. In addition, combined genetic and molecular studies may be performed to develop novel therapeutic targets. For both biliary and pancreatic diseases, imaging plays a pivotal role in initial diagnosis, evaluation of treatment response, efficacy testing of novel drugs, and long-term surveillance.

Bile duct tumors

Bile duct tumors are benign or malignant lesions which may be associated to risk factors or potentially malignant lesions. They constitute an heterogenous entities group with a different biological behavior and prognosis according to location and growth pattern. We revise the role of the radiologist in order to detect, characterize and stage these tumors, specially the importance of their classification when deciding an appropriate management and treatment.

Imaging bile duct tumors: pathologic concepts, classification, and early tumor detection

Cholangiocarcinoma is the most common primary malignancy of the bile ducts which has several predisposing factors such as hepatolithiasis and primary sclerosing cholangitis, and can develop from precancerous conditions such as biliary intraepithelial neoplasia and intraductal papillary neoplasm of the bile duct. As surgical resection of early stage cholangiocarcinoma or precancerous lesions may provide better prognosis, early detection of those lesions is very important. Imaging studies play important roles in the diagnosis of bile duct tumors followed by appropriate management. Indeed, not only diagnosis of cholangiocarcinoma but also appropriate categorization of bile duct tumors based on their morphologic features and location on cross-sectional imaging studies, including computed tomography and magnetic resonance imaging, is important to predict their biologic behaviors, and choose relevant treatment strategies. We herein review the classification system of the bile duct tumors with their radiologic and pathologic findings as well as role of imaging in the early detection of bile duct tumors.

Intraductal papillary neoplasms of the bile duct

Intraductal papillary neoplasm of the bile duct (IPNB) is a rare variant of bile duct tumors characterized by papillary growth within the bile duct lumen and is regarded as a biliary counterpart of intraductal papillary mucinous neoplasm of the pancreas. IPNBs display a spectrum of premalignant lesion towards invasive cholangiocarcinoma. The most common radiologic findings for IPNB are bile duct dilatation and intraductal masses. The major treatment of IPNB is surgical resection. Ultrasonography, computed tomography, magnetic resonance image, and cholangiography are usually performed to assess tumor location and extension. Cholangioscopy can confirm the histology and assess the extent of the tumor including superficial spreading along the biliary epithelium. However, pathologic diagnosis by preoperative biopsy cannot always reflect the maximum degree of atypia, because IPNBs are often composed of varying degrees of cytoarchitectural atypia. IPNBs are microscopically classified into four epithelial subtypes, such as pancreatobiliary, intestinal, gastric, and oncocytic types. Most cases of IPNB are IPN with high-grade intraepithelial neoplasia or with an associated invasive carcinoma. The histologic types of invasive lesions are either tubular adenocarcinoma or mucinous carcinoma. Although several authors have investigated molecular genetic changes during the development and progression of IPNB, these are still poorly characterized and controversial.

Intraductal papillary neoplasm of the bile duct

Intraductal papillary neoplasm of the bile duct (IPNB) is a variant of bile duct carcinoma that is characterized by intraductal growth and better outcomes compared with common cholangiocarcinoma. IPNBs are mainly found in patients from Far Eastern areas, where hepatolithiasis and clonorchiasis are endemic. According to the immunohistochemical profiles of the mucin core proteins, IPNBs are classified into four types: pancreaticobiliary, intestinal, gastric, and oncocytic. Approximately 40%-80% of IPNBs contain a component of invasive carcinoma or tubular or mucinous adenocarcinoma, suggesting that IPNB is a disease with high potential for malignancy. It is difficult to make an accurate preoperative diagnosis because of IPNB’s low incidence and the lack of specificity in its clinical manifestation. The most common abnormal preoperative imaging findings of IPNB are intraductal masses and the involvement of bile duct dilation. Simultaneous proximal and distal bile duct dilation can be detected in some cases, which has diagnostic significance. Cholangiography and cholangioscopy are needed to confirm the pathology and demonstrate the extent of the lesions. However, pathologic diagnosis by biopsy cannot reflect the actual stage in many cases because different foci may be of different stages and because mixed pathologic findings may exist in the same lesion. Surgical resection is the major treatment. Systematic cholangioscopy with staged biopsies and frozen sections is recommended during resection to ensure that no minor tumors are left and that curative resection is achieved. Staging, histologic subtype, curative resection and lymph node metastasis are factors affecting long-term survival.