Intraductal Papillary Neoplasm of the Bile Duct: Clinical, Imaging, and Pathologic Features. AJR Am J Roentgenol. 2018;211:67-75. [PMID: 29629808 DOI: 10.2214/ajr.17.19261]

Intrahepatic intraductal papillary cystic neoplasm of the bile duct: A case report

Introduction and importance

Intraductal papillary neoplasm of the bile duct (IPNB) is a tumour with a very low incidence in the Western world, characterised by a high risk of malignant transformation and unknown prognosis. It is a new entity which was adopted by the WHO in 2010 as a precursor lesion of cholangiocarcinoma. Intrahepatic bile duct is the most common site of origin for IPNB.

Case presentation

Hereby, we present a case of an asymptomatic 63- year-old man, referred to our department after routine ultrasonography showing a multifocal cystic lesion on the left hepatic lobe. Further screening modalities (CT, MRI abdo) confirmed a complex cystic liver lesion with atypical features. The patient underwent left hepatectomy. Histopathology showed a cystic type intrahepatic IPNB, which was completely resected (R0). The follow up in 2 yrs post-operation showed no signs of recurrence.

Clinical discussion

The diagnosis and management of IPNB remain challenging. A multimodality imaging approach is essential in order to diagnose IPNB, assess tumour location and extent and plan the optimal treatment strategy.

Conclusion

Complete surgical resection (R0) with close postoperative follow-up offers long-term survival.

Intraductal Papillary Neoplasm of the Bile Duct: A Rare Case of Intrahepatic Space-Occupying Lesion

Intraductal papillary neoplasm of the bile duct (IPNB) is a rare tumor and is considered one of the precursor lesions for cholangiocarcinoma. Though relatively common in the far east countries, it is uncommon in the Indian population. A 67-year-old gentleman presented with vague upper abdominal pain with no history of fever, jaundice, melena, or hematemesis. An abdominal ultrasound showed a solid cystic lesion in the left lobe of the liver with upstream dilatation of bile ducts. Computed tomography and magnetic resonance imaging showed similar findings. With a differential diagnosis of intrahepatic cholangiocarcinoma, intraductal papillary neoplasm, and biliary cystadenoma, he underwent robotic-assisted left hepatectomy. Histopathology was suggestive of IPNB. Following surgery, he had an uneventful recovery and was advised for follow-up visits every six months. A clinical, radiological, and pathological profile of this rare tumor has been described here with a review of the existing literature.

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

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

Hepatic Mucinous Cystic Neoplasm Versus Simple Biliary Cyst: Assessment of Distinguishing Imaging Features Using CT and MRI

OBJECTIVE. The purpose of our study was to identify the imaging features that differentiate a hepatic mucinous cystic neoplasm (MCN) from a simple biliary cyst. MATERIALS AND METHODS. Surgically resected hepatic MCNs and simple biliary cysts over a 20-year period (October 29, 1997-January 23, 2018) with preoperative CT, MRI, or both were retrospectively identified. Included cases underwent histopathologic confirmation of diagnosis based on the 2010 World Health Organization criteria and blinded imaging review. Various imaging features, including cyst shape and septal enhancement, were assessed for performance. For septate cysts, the relationship of the septation to the cyst wall-that is, arising from the wall without an indentation versus arising from an external macrolobulation-was recorded. Statistical analysis was performed for the imaging features with the chi-square test. RESULTS. The study group comprised 22 hepatic MCNs and 56 simple biliary cysts. A unilocular hepatic cystic lesion was highly predictive of a simple biliary cyst (positive predictive value = 95.2%). The imaging feature of septations arising only from macro-lobulations was 100% specific for a simple biliary cyst on CT (p = 0.001). The presence of septations arising from the cyst wall without indentation was 100% sensitive for hepatic MCN but was only 56.3% specific on CT. Septal enhancement reached 100% sensitivity for hepatic MCN on MRI (p = 0.018). CONCLUSION. The presence of septations, relationship of the septations to the cyst wall, and septal enhancement were sensitive imaging features in the detection of hepatic MCN. The imaging feature of septations arising only from macrolobulations in the cyst wall was specific for simple biliary cysts on CT and helped differentiate simple biliary cysts from hepatic MCNs.

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.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Gastric subtype of intraductal papillary neoplasm of the bile duct: The pathologic spectrum

BACKGROUND AND AIMS

Intraductal papillary neoplasms of bile duct (IPNBs) remain a challenging entity to manage.

METHODS

The pathologic spectrum of 34 gastric subtype of IPNB (gIPNB) cases was examined in consideration of the type 1 and 2 subclassification proposed by Japan-Korea consensus and compared with gastric subtype of pancreatic intraductal papillary mucinous neoplasm (gIPMN) (44 cases).

RESULTS

Type 1 gIPNBs (17 cases) showed regular papillary foveola with variable tubular pyloric glands. Eight of the type 1 gIPNBs showed low-grade dysplasia. Type 2 cases (n = 17) showed complicated papillary and tubular structures and high-grade dysplastic foveola and pyloric glands. Foveolas were predominant in 15 cases, while pyloric glands were predominant in 10 cases, and considerable areas of foveolas and pyloric glands in the remaining: these three were found similarly in type 1 and 2 gIPNB. gIPMNs showed central foveola with a peripheral pyloric gland. Such a pattern was recognizable in type 1 but vague in type 2. Type 1 was frequently found in the intrahepatic bile ducts and showed abundant mucin, as in gIPMNs, while type 2 also occurred in the extrahepatic bile ducts and were pathologically more malignant.

CONCLUSION

Type 1 lesions shared features of gIPMN, while type 2 lesions differed from gIPMN and were more pathologically malignant.

Magnetic Resonance Imaging Findings of Biliary Adenofibroma

Biliary adenofibroma is a rare tumor with a bile duct origin characterized by a complex tubulocystic non-mucin secreting biliary epithelium with abundant fibrous stroma. The MRI features of biliary adenofibroma are not well established. The authors encountered two patients with biliary adenofibroma and reviewed the literature focusing on the MRI findings. A well-circumscribed multicystic tumor with septal enhancement and no intrahepatic bile duct communication may be the characteristic MRI findings of biliary adenofibroma.

Intraductal papillary neoplasm of the bile duct (IPNB): CT and MRI appearance with radiology-pathology correlation

PURPOSE

Intraductal papillary neoplasm of the bile duct (IPNB) is a precursor to invasive carcinoma and is a distinct pathologic diagnosis. The purpose of this study was to evaluate imaging features of IPNB on cross-sectional imaging studies with histopathologic correlation.

MATERIALS AND METHODS

In this IRB approved, HIPAA compliant retrospective observational analysis of 23 pathology proven IPNB tumors 22 imaging studies were reviewed, 14 CT and 8 MRI scans. Features evaluated in consensus by two subspecialty-trained abdominal radiologists included: presence of specific lesion/mass within the bile duct, location within the biliary tree, size, morphology, enhancement characteristics, and bile duct caliber.

RESULTS

Majority of the subjects (16/18, 90%) had definite intraluminal mass, of which 7 (39%) had a polypoid mass with upstream diffuse biliary ductal dilation and 5 (28%) had a plaque-like mass with focal stricture and upstream biliary ductal dilatation. 6/18 (33%) subjects had low grade dysplasia, most commonly intestinal subtype, 7/18 (39%) subjects presented with invasive component, commonly pancreaticobiliary subtype, and 5/18 (28%) presented with high grade dysplasia.

CONCLUSION

IPNB has increased predilection for extrahepatic bile ducts, commonly presenting as either an intraluminal polypoidal mass with associated upstream biliary ductal dilation or a focal plaque like mass with associated ductal stricture at the site of the tumor.

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

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

[Surgical approach to benign bile duct alterations]

BACKGROUND

Benign biliary diseases comprise entities, which present with very similar pathognomonic symptoms despite fundamental etiological differences. Obstructions of intrahepatic and extrahepatic bile ducts due to stones, tumors or parasites as well as stenoses and cystic alterations belong to the group of benign biliary diseases.

OBJECTIVE

This article provides a systematic overview of the indications and differential treatment of benign biliary diseases with special emphasis on the surgical treatment.

MATERIAL AND METHODS

The presented recommendations are in accordance with national and international guidelines, current scientific papers and expert opinions.

RESULTS

Essentially the surgical options for benign biliary diseases consist of revision, reconstruction through bilioenteric anastomosis, resection and complete organ replacement in the sense of liver transplantation. The location of the affected segment of the biliary tree, the symptoms, the progress of the disease and suspected malignancy essentially determine the level of escalation in the described treatment level scheme.

CONCLUSION

The treatment of benign biliary diseases is complex and requires achievement of unimpaired, unobstructed bile drainage. It serves the purpose of resolving cholestasis and thereby avoiding recurrent cholangitis and long-term complications, such as biliary cirrhosis and malignant transformation; however, in some cases of premalignant lesions of the bile ducts the strategy resembles cancer surgery, including resection of the affected tissue.

Imaging findings for mucinous tumors of the abdomen and pelvis

This article aims to describe the imaging findings for mucinous tumors of the abdomen and pelvis, which have a similar appearance on imaging tests regardless of the organ in which they develop. Due to the high water content of mucus, the appearance of these tumors is generally similar to that of water on ultrasonography, computed tomography, and magnetic resonance imaging. Another common feature of mucin-producing tumors is that calcifications are often present. The rupture of these lesions and accumulation of mucinous material in the peritoneal cavity gives rise to pseudomyxoma peritonei. It is important to identify mucinous tumors because they have a different prognosis and clinical course than non-mucinous tumors and require different management. Depending on their anatomic location and their imaging characteristics, the treatment approach varies from follow-up to radical surgery together with chemotherapy or radiotherapy or both.

CT imaging comparison between intraductal papillary neoplasms of the bile duct and papillary cholangiocarcinomas

OBJECTIVES

To identify imaging features that assist in discriminating intraductal papillary neoplasms of the bile duct (IPNBs) from papillary cholangiocarcinomas (PCCs).

METHODS

This study was approved by the institutional review board. Using the recently proposed histological diagnostic criteria for biliary papillary neoplasms, IPNBs and PCCs were selected from 537 biliary neoplasms consecutively resected in a 12.5-year period. Clinical and imaging features were compared between the two groups.

RESULTS

The histology review identified 19 IPNBs and 48 PCCs, representing an estimated prevalence of IPNBs among biliary neoplasms of 4%. Approximately one half of IPNBs were incidentally found on imaging conducted for other purposes. In terms of tumor location, 15/19 IPNBs (79%) developed in intrahepatic bile ducts, and 41/48 PCCs (85%) in the distal bile duct. Cystic appearance was highly suggestive for IPNBs (p < 0.001). Using these two parameters, 78% of papillary bile duct neoplasms could be classified into IPNBs or PCCs. Other imaging findings favoring IPNBs included frond-like mural nodule, downstream bile duct dilatation, and the lack of abnormal enhancement in the adjacent bile duct. Interestingly, two patients with non-invasive or microinvasive IPNB had undergone abdominal imaging studies > 3 years before, and a retrospective review of the previous images identified small nodular or cystic lesions, suggesting a less progressive nature of IPNBs than currently thought.

CONCLUSIONS

Imaging findings useful for discriminating IPNBs from PCCs appear to be tumor location, shape of tumor, appearance of mural nodules, duct dilatation at unaffected duct, and abnormal enhancement of the adjacent bile duct.

KEY POINTS

• Intrahepatic location and cystic dilatation of the affected bile duct are the strong discriminators between IPNBs and PCCs. • The shape of the mural nodule and appearance of the neighboring bile duct are helpful for distinguishing IPNBs and PCCs. • The less aggressive behavior of IPNBs compared with PCCs may facilitate less invasive management in patients with IPNB.