Radiologic spectrum of cholangiocarcinoma: emphasis on unusual manifestations and differential diagnoses

Gallbladder and biliary pathology: lessons learned from multidisciplinary conference

The radiologic diagnosis of biliary disease can be challenging due to atypical or delayed presentation, rare or less common entities, and imaging overlap of benign and malignant processes. Establishing a specific diagnosis, when possible, is important to avoid progression of infections to sepsis and multiorgan failure, and for appropriate staging and management in cases of malignancy. Gallstones are the most common biliary disease, and along with stone-related complications, including cholecystitis and choledocholithiasis, constitute the majority of acute biliary pathology. Late and atypical manifestations of acute cholecystitis demonstrate imaging overlap with primary gallbladder cholangiocarcinoma, especially with cases of exuberant inflammatory reaction such as xanthogranulomatous cholecystitis. Additional challenging scenarios related to gallbladder disease, that may be benign or malignant, include adjacent fistulas and lymphadenopathy. Dropped gallstones, especially in atypical locations, may be misdiagnosed as neoplastic. Recurrent cholecystitis after cholecystectomy, whether related to subtotal cholecystectomy or to stumpitis, is another entity that can be confusing to the radiologist with a documented history of cholecystectomy. Inflammatory and autoimmune conditions, such as pseudotumors and IgG4 disease, are a less common but not infrequent cause of diagnostic dilemma. Furthermore, biliary strictures and hepatobiliary cystic lesions can be benign or malignant and could constitute a diagnostic and management challenge. The goal of this manuscript is to present the lessons learned from multidisciplinary conferences on the above entities and suggest tips and pearls to maximize the value of radiologists' contribution to patient management.

Imaging mimickers of cholangiocarcinoma: a pictorial review

Cholangiocarcinoma (CCA) is the second most common primary hepatobiliary malignancy and presents as three separate morphological subtypes; namely mass-forming, periductal-infiltrating, and intraductal-growing patterns. Each of these subtypes have distinct imaging characteristics, as well as a variety of benign and malignant mimics, making accurate diagnosis of CCA on imaging challenging. Whilst histopathological examination is required to arrive at a definitive diagnosis, it is still important for radiologists to be cognizant of these entities and provide reasonable differential diagnoses, as these potentially have a large impact on patient management. This pictorial essay illustrates the three morphological subtypes of CCA, as well as some important mimics for each subtype, that are encountered in clinical practice.

Imaging Spectrum of Intrahepatic Mass-Forming Cholangiocarcinoma and Its Mimickers: How to Differentiate Them Using MRI

Intrahepatic cholangiocarcinoma (ICC) is the second most common primary hepatic malignancy, with mass-forming growth pattern being the most common. The typical imaging appearance of mass-forming ICC (mICC) consists of irregular ring enhancement in the arterial phase followed by the progressive central enhancement on portal venous and delayed phases. However, atypical imaging presentation in the form of hypervascular mICC might also be seen, which can be attributed to distinct pathological characteristics. Ancillary imaging features such as lobular shape, capsular retraction, segmental biliary dilatation, and vascular encasement favor the diagnosis of mICC. Nevertheless, these radiological findings may also be present in certain benign conditions such as focal confluent fibrosis, sclerosing hemangioma, organizing hepatic abscess, or the pseudosolid form of hydatid disease. In addition, a few malignant lesions including primary liver lymphoma, hemangioendothelioma, solitary hypovascular liver metastases, and atypical forms of hepatocellular carcinoma (HCC), such as scirrhous HCC, infiltrative HCC, and poorly differentiated HCC, may also pose a diagnostic dilemma by simulating mICC in imaging studies. Diffusion-weighted imaging and the use of hepatobiliary contrast agents might be helpful for differential diagnosis in certain cases. The aim of this manuscript is to provide a comprehensive overview of mICC imaging features and to describe useful tips for differential diagnosis with its potential mimickers.

Diagnostic Accuracy of Magnetic Resonance Cholangiopancreatography to Detect Benign and Malignant Biliary Strictures

Background:

Magnetic resonance cholangiopancreatography (MRCP) is a noninvasive method to detect pancreaticobiliary strictures. In this study, we aimed to evaluate the diagnostic performance of MRCP and detect sensitive and specific radiologic features in distinguishing malignant and benign pathologies.

Materials and Methods:

In this study, 50 patients with biliary obstruction and a confirmed diagnosis using histopathology were included. The pathologies were evaluated using MRCP which were categorized into malignant and benign strictures. The etiology of strictures was detected using histopathology and endoscopic retrograde cholangiopancreatography. The diagnostic performance of MRCP was calculated using SPSS software. P < 0.05 was considered statistically significant.

Results:

Of 50 patients, 23 patients (46%) had malignant strictures based on MRCP and histopathology. The sensitivity and specificity of MRCP to detect malignancy were 95.7% and 96.3%, respectively. The most sensitive MRCP features to detect malignancy were upstream biliary duct dilation, abrupt tapering, and the presence of a solid mass with sensitivity 100%, 95.7%, and 78.2%, respectively. The malignancy rate was significantly higher in the strictures with length >11.5 mm or wall thickness >2.75 mm (P < 0.05).

Conclusion:

MRCP is a sensitive method to differentiate malignant lesions from benign pathologies. A long and thick stricture with the presence of a solid mass, upstream biliary duct dilation, and abrupt tapering is highly suggestive of malignancy.

Imaging features of intrahepatic cholangiocarcinoma mimicking a liver abscess: an analysis of 8 cases

Background

In rare cases, intrahepatic cholangiocarcinoma can present as a pyogenic liver abscess and are often misdiagnosed. This study aimed to analyze the imaging features of intrahepatic cholangiocarcinoma mimicking a pyogenic liver abscess.

Methods

The clinical data and imaging results of eight patients with pathologically confirmed intrahepatic cholangiocarcinoma mimicking a liver abscess were retrospectively collected.

Results

The mean age was 58 years with a range of 46–68 years. Fever and leukocytosis were present in six patients. All the eight lesions were a single mass. Air–liquid levels were present in two patients. Only one patient showed hepatic lobar atrophy and hepatic capsule retraction. The double target sign of liver abscess was not noticed in the CT/MRI images of all eight patients. The inner wall of the lesion was rough and irregular, with multiple dot/patchy and wall nodule enhancements. The abscess wall and the marginal parenchyma were supplied by the hepatic artery in four patients, and the intralesional arteries were rough and disrupted. Bile duct dilatation was seen adjacent to the lesion. In seven patients, diffusion-weighted images showed irregular patchy restricted diffusion in the marginal parenchyma of the necrotic area in addition to the prominent restricted diffusion in the necrotic area. Two patients with cholangiolithiasis showed patchy slight CT hypodensity, slight T1 hypointensity, slight T2 hyperintensity, and patchy delayed enhancement. Multiple lymph nodes enlargement in the hepatic hilar area and the retroperitoneal space were seen in five patients.

Conclusion

Intrahepatic cholangiocarcinoma mimicking a pyogenic liver abscess have unique imaging features and require careful image examination to avoid misdiagnosis.

Magnetic Resonance Imaging of Nonhepatocellular Malignancies in Chronic Liver Disease

Hepatocellular carcinoma (HCC) is the most common liver malignancy associated with chronic liver disease. Nonhepatocellular malignancies may also arise in the setting of chronic liver disease. The imaging diagnosis of non-HCC malignancies may be challenging. Non-HCC malignancies in patients with chronic liver disease most commonly include intrahepatic cholangiocarcinoma and combined hepatocellular-cholangiocarcinoma, and less commonly hepatic lymphomas and metastases. On MR imaging, non-HCC malignancies often demonstrate a targetoid appearance, manifesting as rim arterial phase hyperenhancement, peripheral washout, central delayed enhancement, and peripheral restricted diffusion. When applying the Liver Imaging Reporting and Data System algorithm, observations with targetoid appearance are categorized as LR-M.

Cholangiocarcinoma - Part 2, Tumoral and Nontumoral Mimics and Imaging Features Helpful in Differentiation

Each of the 3 morphological subtypes of cholangiocarcinoma has a different set of imaging differentials. Emulators of mass-forming cholangiocarcinoma include other primary and secondary hepatic malignancies, benign tumors and tumor-like mimics such as abscess, hemangioma and confluent hepatic fibrosis. Benign inflammatory biliary strictures constitute the major differential of periductal-infiltrative type and intraductal calculi are the main consideration for intraductal-growth type. CT and MRI are the standard imaging tools for characterization of cholangiocarcinoma and differentiating it from close mimics. Here we will describe the various tumoral and non-tumoral mimics of cholangiocarcinoma and discuss specific imaging features useful in differentiation.

Italian Clinical Practice Guidelines on Cholangiocarcinoma - Part I: Classification, diagnosis and staging

Cholangiocarcinoma (CCA) is the second most common primary liver cancer, characterized by a poor prognosis and resistance to chemotherapeutics. The progressive increase in CCA incidence and mortality registered worldwide in the last two decades and the need to clarify various aspects of clinical management have prompted the Italian Association for the Study of the Liver (AISF) to commission the drafting of dedicated guidelines in collaboration with a group of Italian scientific societies. These guidelines have been formulated in accordance with the Italian National Institute of Health indications and developed by following the GRADE method and related advancements.

Rare Clinical and Radiologic Case of Cholangiocarcinoma Mimicking Pyogenic Abscess, Hepatic Echinococcal Cysts, and Metastases

Cholangiocarcinoma is a biliary carcinoma with a wide spectrum of imaging, histological, and clinical features. In immunocompromised patients, pyogenic abscesses are relatively common and an echinococcal hepatic cysts are very rare. The authors experienced a very rare case of cholangiocarcinoma showing multiple hypodense masses with wall enhancement mimicking pyogenic liver abscess, echinococcal hepatic cyst, and cystic metastases. An 83-year-old man, complaining of fatigue and poor oral intake, presented to our outpatient clinic. Abdominal computed tomography (CT) revealed multiple, variable-sized hypodense masses with peripheral rim enhancement throughout the liver. Dynamic liver magnetic resonance images also showed findings similar to those of a CT scan. We performed ultrasound-guided biopsy of the mass which revealed cholangiocarcinoma.

Pearls and pitfalls in magnetic resonance imaging of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the most common primary hepatic malignancy, which usually arises in cirrhotic liver. When the typical enhancement pattern, consisting of late arterial hyperenhancement followed by washout, is present in nodules larger than 1 cm, HCC can be confidently diagnosed without the need for tissue biopsy. Nevertheless, HCC can display an atypical enhancement pattern, either as iso or hypovascular lesion, or hypervascular lesion without washout. Not only the enhancement pattern of HCC could be atypical, but also a variety of histological types of HCC, such as steatotic, scirrhous, fibrolamellar, or combined hepatocellular-cholangiocellular carcinoma could raise diagnostic dilemmas. In addition, distinct morphological types of HCC or different growth pattern can occur. Awareness of these atypical and rare HCC presentations on magnetic resonance imaging is important for accurate differentiation from other focal liver lesions and timely diagnosis, which allows optimal treatment of patients.

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.

Infiltrative non-mass-like hepatocellular carcinoma initially presenting with isolated malignant portal vein thrombosis: A case report and review of the literature

Hepatocellular carcinoma (HCC) shows a rising incidence and mortality rates worldwide. HCC is divided into several distinct subtypes, both morphologically and histopathologically. Among these subtypes, infiltrative HCC may be the most challenging subtype to diagnose, given its characteristic myriad of tumor nodules blended with normal hepatocytes without a distinct mass-like lesion. Herein, we report an unusual case of an infiltrative HCC initially presenting with isolated malignant portal vein thrombosis and provide a brief review of the literature regarding the infiltrative HCC subtype. Additionally, we demonstrate how sonoelastography could aid in detecting the appropriate biopsy area in the infiltrative HCC subtype. To our knowledge, there have not been previously reported cases describing the use of sonoelastography in the evaluation of the appropriate area for the targeted liver biopsy.

Ecografía en cirugía general

La ecografía es un estudio de imágenes diagnósticas con una amplia historia de uso en todas las especialidades de la Medicina; su advenimiento ha ayudado al enfoque diagnóstico e, incluso, al abordaje terapéutico de los pacientes. Desde su origen en el siglo XIX con mediciones de la velocidad del sonido en el agua, hasta el desarrollo de las máquinas de ultrasonografía sustentadas en los avances de la tecnología, la física y la ingeniería, se ha utilizado de manera notable en la Medicina. No hay duda de que, en el campo de la Cirugía General, ha sido útil para el manejo de los pacientes con enfermedad abdominal. La tecnología ecográfica permite identificar las características de un órgano normal y, cuando este patrón se afecta, orienta sobre la causa o determina la enfermedad que puede estar produciendo la alteración. En la presente revisión, se hace un recuento histórico del nacimiento de la ecografía, su aplicación en el campo de la medicina y su utilidad para el cirujano general en diversas circunstancias de la práctica quirúrgica.

Cancer risk in primary sclerosing cholangitis: Epidemiology, prevention, and surveillance strategies

Primary sclerosing cholangitis (PSC) is a rare cholestatic liver disease characterized by progressive fibroinflammatory destruction of the intra- and/or extrahepatic biliary ducts. While its features and disease course can be variable, most patients with PSC have concurrent inflammatory bowel disease and will eventually develop liver cirrhosis and end-stage liver disease, with liver transplantation representing the only potentially curative option. Importantly, PSC is associated with a significantly increased risk of malignancy compared to the general population, mainly cholangiocarcinoma, gallbladder carcinoma, hepatocellular carcinoma, and colorectal cancer, with nearly 50% of deaths in patients with PSC being due to cancer. Therefore, robust surveillance strategies are needed, though uncertainty remains regarding how to best do so. In this review, we discuss the epidemiology, prevention, and surveillance of cancers in patients with PSC. Where evidence is limited, we present pragmatic approaches based on currently available data and expert opinion.

[Role of magnetic resonance imaging in preoperative assessement of hilar cholangiocarcinoma]

Magnetic resonance cholangiopancreatography is a non-invasive imaging, highly performant in detecting and locating biliary stenosis and in predicting its malignancy. The combination of two and three-dimensional MRI sequences is recommended to assess a biliary obstacle. Cholangiopathies are the main differential diagnosis of cholangiocarcinomas. In addition to bile duct abnormalities beyond the stenosis, the predictive signs of malignancy are: asymmetric irregular luminal narrowing (longer than 3mm and thicker than 13mm), abrupt discontinuation of stenosis, and enhancement superior to that of the adjacent hepatic parenchyma during arterial and portal acquisitions. Diffusion sequences improve the sensitivity of biliary stenosis detection. Moreover, restriction of diffusion is useful for distinguishing malignant from benign stenosis. Combining Magnetic resonance cholangiopancreatography, late LAVA and diffusion sequences improves the sensitivity of detection of a possible biliary extension without significant specificity. MRI with gadolinium chelate injection is efficient in assessing vascular extension of cholangiocarcinomas. However its accuracy remains lower than that of Ct-scan. To assess hepatic, lymphatic and peritoneal extensions of cholangiocarcinomas, it is fundamental to combine diffusion and dynamic MRI sequences.

Intrahepatic mass-forming cholangiocarcinoma and solitary hypovascular liver metastases: is the differential diagnosis using diffusion-weighted MRI possible?

Background Intrahepatic mass-forming cholangiocellular carcinoma (IMC) is the second most common primary liver tumor. The differentiation between IMC and solitary hypovascular liver metastases (SHLM) represents a diagnostic challenge due to many overlapping magnetic resonance imaging (MRI) features. Purpose To determine the value of diffusion-weighted imaging (DWI) in addition to conventional MRI for the distinction between intrahepatic mass-forming cholangiocarcinoma and solitary hypovascular liver metastases. Material and Methods Fifty-three patients with pathologically proven IMC (n = 31) and SHLM (n = 22) who had undergone MRI and DWI before surgery or percutaneous biopsy were enrolled in this study. The following MRI features were analyzed: the size and shape of the lesion, presence of capsular retraction and segmental biliary dilatation, T2-weighted (T2W) signal intensity, the presence of target sign on DWI and enhancement pattern. Apparent diffusion coefficient (ADC) values were calculated for each lesion ( b = 800 s/mm²). Univariate and multivariate logistic regression analyses were used to identify significant differentiating features between IMCs and SHLMs. Results Univariate analysis revealed that following parameters favor diagnosis of IMCs over SHLMs: lobulating shape, heterogeneous T2W signal intensity, capsular retraction, segmental biliary dilatation, target sign on DWI and rim-like enhancement on arterial phase followed by progressive enhancement in delayed phases. ADC values measured in the periphery of the lesion were significantly lower in IMCs in comparison to SHLMs. Multivariate analysis revealed that target sign on DWI was the most significant predictor of IMCs. Conclusion Qualitative DWI analysis with target sign significantly improves diagnostic accuracy for differentiation among IMC and SHLM lesions.

Primary malignant tumours in the non-cirrhotic liver

Intrahepatic chlangiocarcinomas (CCs), the second most common primary malignant liver tumours, usually occur in non-cirrhotic liver, and can be classified into three types based on gross morphology: mass-forming; periductal infiltrating; and intraductal growing. Among them, mass-forming intrahepatic CCs are the most common type and characterized by homogeneous mass with an irregular but well-defined margin with peripheral enhancement on late arterial phase and delayed enhancement in central portion of tumours corresponding to the fibrous stroma. Several imaging features such as enhancement pattern and degree of diffusion restriction have been suggested as prognostic markers for mass-forming CCs. Hepatocellular carcinomas (HCCs) are the most common primary malignant liver tumors, and usually arise from the cirrhotic liver. However, approximately 20% of HCCs involve the non-cirrhotic liver (hereafter, non-cirrhotic HCC), and non-cirrhotic HCCs are often detected at an advanced stage due to the lack of surveillance for patients with non-cirrhotic liver. Other primary malignant liver tumours other than CCs and HCCs including angiosarcoma, undifferentiated embryonal sarcoma are quite rare, and imaging diagnosis is often difficult. This review offers a brief overview of epidemiology, risk factors and imaging features of primary malignant tumours in non-cirrhotic liver. Understanding of radiologic appearance and predisposing clinical features as well as differentials of primary malignant tumour in non-cirrhotic liver can be helpful for radiologists to adequately assess these tumours, and subsequently to make optimal management plan.

Intratumoral artery on contrast-enhanced computed tomography imaging: differentiating intrahepatic cholangiocarcinoma from poorly differentiated hepatocellular carcinoma

AIM

Differentiating intrahepatic cholangiocarcinoma (ICC) from poorly differentiated hepatocellular carcinoma (p-HCC) is often difficult, but it is important for providing appropriate treatments. The purpose of this study was to examine the features differentiating ICC from p-HCC on contrast-enhanced dynamic-computed tomography (CT).

METHODS

This study examined 42 patients with pathologically confirmed ICC (n = 19) or p-HCC (n = 23) for which contrast-enhanced dynamic CT data were available. CT images were analyzed for enhancement patterns during the arterial phase, washout pattern, delayed enhancement, satellite nodules, capsular retraction, lesion shape, and presence of an intratumoral hepatic artery, intratumoral hepatic vein, intratumoral portal vein, and bile duct dilation around the tumor, portal vein tumor thrombus, lobar atrophy, or lymphadenopathy.

RESULTS

Univariate analysis revealed the presence of rim enhancement (p = 0.037), lobulated shape (p = 0.004), intratumoral artery (p < 0.001), and bile duct dilation (p = 0.006) as parameters significantly favoring ICC, while a washout pattern significantly favored p-HCC (p < 0.001). Multivariate analysis revealed intratumoral artery as a significant, independent variable predictive of ICC (p = 0.037), and 15 ICCs (78.9%) showed this feature. Washout pattern was a significant, independent variable favoring p-HCC (p = 0.049), with 15 p-HCCs (65.2%) showing this feature.

CONCLUSION

The presence of an intratumoral artery in the arterial phase on contrast-enhanced dynamic CT was a predictable finding for ICC, and the presence of a washout pattern was a predictable finding for p-HCC, differentiating between ICC and p-HCC.

How to not miss alveolar echinococcosis in hepatic lesions suspicious for cholangiocellular carcinoma

PURPOSE

Hepatic alveolar echinococcosis (AE) resembles intrahepatic cholangiocarcinoma (ICC) on radiological imaging. The purpose of this study was to identify criteria to discriminate AE from ICC with CT and MR Imaging.

METHODS

One hundred and sixteen imaging studies of 94 patients (CT n = 65; MRI n = 51) diagnosed with AE (n = 55) or ICC (n = 39) were retrospectively reviewed by two blinded radiologists for lesion features including enhancement pattern and matrix composition. A consensus read was conducted in cases of disagreement. Uni- and multivariate logistic regression with bootstrapping were used for analysis.

RESULTS

Using CT, no or septal enhancement and calcification yielded the highest values of sensitivity/specificity (90.9%/90.6% and 81.8%/96.9%) for AE. Using MRI, no or septal enhancement and cystic components achieved the highest sensitivity/specificity (90.9%/100.0% and 84.8%/66.7%) for AE. Multivariate logistic regression identified the following strong independent predictors for AE: for MRI, no or septal enhancement (odds ratio [OR] 322.4; p < 0.001); for CT, no or septal enhancement and calcification (OR 35.9 and 42.5; p < 0.001 and p < 0.01, respectively). No or septal enhancement and calcification demonstrated the highest interreader agreement (>90%).

CONCLUSION

Enhancement characteristics and matrix calcifications offer the strongest discriminating potential between AE and ICC with a high sensitivity, specificity, and interreader agreement.

Mass-forming cholangiocarcinoma and adenocarcinoma of unknown primary: can they be distinguished on liver MRI?

PURPOSE

To determine MR features suggestive of mass-forming cholangiocarcinoma (CCA) or liver metastases of adenocarcinoma of unknown primary (AUP), and to compare the ability of two experienced radiologists to establish the correct diagnosis.

MATERIALS AND METHODS

61 patients with CCA or AUP, with MRIs were placed into two groups: population 1, 28 patients with certain diagnosis of either CCA or AUP; and population 2, 33 patients with uncertain diagnosis. Using population 1 with known diagnosis, two investigators formulated imaging criteria for CCA or AUP, which represented phase 1 of the study. In phase 2, two independent radiologists categorized the patients in populations 1 and 2 as CCA or AUP using the formulated criteria. This categorization was compared with the patient medical records and pathologist review. Findings were tested for statistical significance.

RESULTS

In phase 1, solitary lesion, multifocal lesions with dominant lesion, capsule retraction, and porta hepatis lymphadenopathy were features of CCA; multifocal lesions with similar size, and ring enhancement were features of AUP. The number of lesions, capsule retraction, and early tumor enhancement pattern were observed to be significant features (P < 0.05). In phase 2, agreement between the two radiologists was good (k = 0.663). For population 1, the agreement was good (k = 0.659), and was fair for population 2 (k = 0.293). Concordance between the two radiologists, medical record, and the pathologist was found in 41/61 (67%) patients.

CONCLUSION

Distinctive features of CCA and AUP are identifiable on MRI images, which may aid the radiologist to establish the correct diagnosis.

Endoscopic management of hilar biliary strictures

Hilar biliary strictures are caused by various benign and malignant conditions. It is difficult to differentiate benign and malignant strictures. Postcholecystectomy benign biliary strictures are frequently encountered. Endoscopic management of these strictures is challenging. An endoscopic method has been advocated that involves placement of increasing number of stents at regular intervals to resolve the stricture. Malignant hilar strictures are mostly unresectable at the time of diagnosis and only palliation is possible.Endoscopic palliation is preferred over surgery or radiological intervention. Magnetic resonance cholangiopancreaticography is quite important in the management of these strictures. Metal stents are superior to plastic stents. The opinion is divided over the issue of unilateral or bilateral stenting.Minimal contrast or no contrast technique has been advocated during endoscopic retrograde cholangiopancreatography of these patients. The role of intraluminal brachytherapy, intraductal ablation devices, photodynamic therapy, and endoscopic ultrasound still remains to be defined.

Adult bile duct strictures: role of MR imaging and MR cholangiopancreatography in characterization

Bile duct strictures in adults are secondary to a wide spectrum of benign and malignant pathologic conditions. Benign causes of bile duct strictures include iatrogenic causes, acute or chronic pancreatitis, choledocholithiasis, primary sclerosing cholangitis, IgG4-related sclerosing cholangitis, liver transplantation, recurrent pyogenic cholangitis, Mirizzi syndrome, acquired immunodeficiency syndrome cholangiopathy, and sphincter of Oddi dysfunction. Malignant causes include cholangiocarcinoma, pancreatic adenocarcinoma, and periampullary carcinomas. Rare causes include biliary inflammatory pseudotumor, gallbladder carcinoma, hepatocellular carcinoma, metastases to bile ducts, and extrinsic bile duct compression secondary to periportal or peripancreatic lymphadenopathy. Contrast material-enhanced magnetic resonance (MR) imaging with MR cholangiopancreatography is extremely helpful in the noninvasive evaluation of patients with obstructive jaundice, an obstructive pattern of liver function, or incidentally detected biliary duct dilatation. Some of these conditions may show characteristic findings at MR imaging-MR cholangiopancreatography that help in making a definitive diagnosis. Although endoscopic retrograde cholangiopancreatography with tissue biopsy or surgery is needed for the definitive diagnosis of many of these strictures, certain MR imaging characteristics of the narrowed segment (eg, thickened wall, long-segment involvement, asymmetry, indistinct outer margin, luminal irregularity, hyperenhancement relative to the liver parenchyma) may favor a malignant cause. Awareness of the various causes of bile duct strictures in adults and familiarity with their appearances at MR imaging-MR cholangiopancreatography are important for accurate diagnosis and optimal patient management.

MRI of cholangiocarcinoma

Cholangiocarcinomas are the second most common primary hepatobiliary tumors after hepatocellular carcinomas. They can be categorized either based on their location (intrahepatic/perihilar/extrahepatic distal) or their growth characteristics (mass-forming/periductal-infiltrating/intraductal) because they exhibit varied presentations and outcomes based on their location and or pattern of growth. The increased risk of cholangiocarcinoma in PSC necessitates close surveillance of these patients by means of imaging and laboratory measures; and because currently surgical resection is the only effective treatment for cholangiocarcinoma, the need for accurate pre-operative staging and assessment of resectability has emphasized the role of high quality imaging in management. Today magnetic resonance imaging (MRI) is the modality of choice for detection, pre-operative staging and surveillance of cholangiocarcinoma.

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.

Endomicroscopy in bile duct: Inflammation interferes with pCLE applied in the bile duct: A prospective study of 54 patients

BACKGROUND

The preoperative diagnosis of biliary stenosis is associated with low accuracy. As a consequence, probe-based confocal laser endomicroscopy (pCLE), an in-vivo histological imaging technique, was applied in the bile duct. The aim of this study was to establish whether previous inflammation of the bile duct affects confocal interpretation. The findings from pCLE were compared in two groups of patients: those in whom there had been no cholangitis nor stenting and those in whom stents had been used and subsequently retrieved or who had suffered cholangitis.

PATIENTS AND METHODS

pCLE was performed on 54 patients (mean age 66 years; 31 men, 23 women) from September 2008 to July 2011. Patients were divided in two groups: group 1: 39 patients who had not undergone a biliary procedure in the month preceding the pCLE procedure; and group 2: 15 patients who had undergone stent placement or presented with cholangitis in the month preceding the pCLE procedure. Endoscopic and pCLE data were collected prospectively. pCLE results were compared to benchmark histology (surgery, endoultrasonography, percutaneous biopsy). Patients with a benign stricture who did not undergo operation were followed for 1 year. pCLE images of the bile duct were obtained during endoscopic retrograde cholangiopancreatography procedures. pCLE images were interpreted prospectively using the Miami classification in vivo and in real time.

RESULTS

In group 1, sensitivity, specificity, and accuracy were 88, 83, and 87%, respectively. In group 2, sensitivity, specificity, and accuracy were 75, 71, and 73%, respectively. Diagnostic accuracy of pCLE was lower when applied to group 2 (p < 0,001). The investigation is less reliable in bile ducts affected by inflammation from cholangitis or previous stenting.

CONCLUSIONS

Inflammatory lesions of the bile duct interfere with interpretation of pCLE. A refined pCLE description of inflammatory lesions should improve accuracy of pCLE in bile duct stenosis.

The role of diffusion-weighted MR imaging for differentiating benign from malignant bile duct strictures

OBJECTIVES

To assess the added value of diffusion-weighted imaging (DWI) to conventional magnetic resonance imaging (MRI) for differentiating benign from malignant bile duct strictures.

METHODS

Twenty-seven patients with a benign stricture and 42 patients with a malignant stricture who had undergone gadoxetic acid-enhanced MRI with DWI were enrolled. Qualitative (signal intensity, dynamic enhancement pattern) and quantitative (wall thickness and length) analyses were performed. Two observers independently reviewed a set of conventional MRI and a combined set of conventional MRI and DWI, and receiver operating characteristic (ROC) curve analysis was assessed.

RESULTS

Benign strictures showed isointensity (18.5-70.4 %) and a similar enhancement pattern (22.2 %) to that of normal bile duct more frequently than malignant strictures (0-40.5 % and 0 %) on conventional MRI (P < 0.05). Malignant strictures (90.5-92.9 %) showed hypervascularity on arterial and portal venous phase images more frequently than benign strictures (37.0-70.4 %) (P < 0.01) On DWI, all malignant strictures showed hyperintensity compared with benign cases (70.4 %) (P < 0.001). Malignant strictures were significantly thicker and longer than benign strictures (P < 0.001). The diagnostic performance of both observers improved significantly after additional review of DWI.

CONCLUSIONS

Adding DWI to conventional MRI is more helpful for differentiating benign from malignant bile duct strictures than conventional MRI alone.

KEY POINTS

• Accurate diagnosis and exclusion of benign strictures of bile duct are important. • Diffusion-weighted MRI helps to distinguish benign from malignant bile duct strictures. • DWI plus conventional MRI provides superior diagnostic accuracy to conventional MRI alone.

The clinical value of dual-time point 18F-FDG PET/CT for differentiating extrahepatic cholangiocarcinoma from benign disease

PURPOSE

The aim of this study was to assess the value of dual-time point PET/CT in the differentiation of extrahepatic cholangiocarcinoma from benign stricture and the added benefits of delayed PET/CT image.

PATIENTS AND METHODS

Thirty-nine patients with suspected extrahepatic biliary malignancy based on conventional imaging studies such as ultrasonography, CT, and MRI between July 2008 and December 2010 were included. All patients underwent dual-time point PET/CT scans at 1 and 2 hours after radiotracer injection. From the site of suspected malignancy, the SUVmax for both time points (SUVmax1 and SUVmax2), the percent change in SUVmax between the 2 (Δ%SUVmax) and the ratio of SUVmax1, SUVmax2, Δ%SUVmax in comparison with average SUV of right hepatic lobe (T/L ratio1, T/L ratio2, and Δ%T/L ratio) were generated. Diagnostic performances using visual assessment and various SUVmax cutoff values were analyzed in the differential diagnosis of extrahepatic cholangiocarcinoma from benign disease. PET/CT results were correlated with histological results and radiological follow-up for at least 6 months.

RESULTS

Of 39 patients, the final diagnosis was cholangiocarcinoma in 34 and benign disease in 5. Between malignant and benign lesions, there were significant differences in SUVmax1 (5.43 ± 4.66 vs 2.26 ± 0.83, P = 0.003) and SUVmax2 (6.02 ± 5.26 vs 2.26 ± 0.76, P = 0.002). There was no significant difference in Δ%SUVmax, T/L ratio1, T/L ratio2, and Δ%T/L ratio. On receiver operator curve analysis, SUVmax1 with cutoff value of 2.5 demonstrated sensitivity of 97.6%, specificity of 60.0%, and accuracy of 92.3% and SUVmax2 with cutoff value of 3.1 demonstrated sensitivity of 88.2%, specificity of 100%, and accuracy of 89.7%.

CONCLUSION

SUVmax from both early and delayed PET/CT scans are useful parameters in the differentiation of extrahepatic biliary malignancy from benign disease. However, there was no added benefit of delayed PET/CT in patients suspicious for extrahepatic cholangiocarcinoma.

Feasibility of using wire-guided needle-knife electrocautery for refractory biliary and pancreatic strictures

BACKGROUND

Endoscopic management of biliary or pancreatic strictures by stent insertion is well established. However, some high-grade strictures are refractory to dilation and stent placement with conventional methods.

OBJECTIVE

To evaluate the safety and efficacy of the wire-guided electrotomy technique in dilating stiff biliary and/or pancreatic stenoses when ordinary methods failed.

DESIGN

Retrospective analysis of a prospective database.

SETTING

Tertiary referral university hospital.

PATIENTS

This study involved 279 patients with biliary or pancreatic strictures who underwent ERCP for stenting.

INTERVENTION

After conventional dilation failed, wire-guided needle-knife electrocautery was attempted to facilitate insertion of the dilating devices and eventually endoprosthesis.

MAIN OUTCOME MEASUREMENTS

The successful treatment and drainage of biliary or pancreatic strictures.

RESULTS

With wire-guided needle-knife cauterization, the success rate of stricture dilatation increased from 95.7% (267 of 279 patients) to 98.9% (276 of 279 patients). Dilation of stenoses was successful in 9 of 10 patients (90%) by using electrocautery with the wire-guided needle-knife technique. Postprocedure adverse events included self-limited bleeding, mild acute pancreatitis, hyperamylasemia, cholangitis, and biliary perforation. No procedure-related death occurred.

LIMITATIONS

Retrospective, single-center study and small sample size.

CONCLUSIONS

Wire-guided needle-knife electroincision appears to be effective for traversing refractory biliary or pancreatic strictures and can be considered as an alternative approach to conventional methods. However, the safety of such a technique needs to be further evaluated.

Klatskin-like lesions

Hilar cholangiocarcinoma, also known as Klatskin tumour, is the commonest type of cholangiocarcinoma. It poses unique problems in the diagnosis and management because of its anatomical location. Curative surgery in the form of major hepatic resection entails significant morbidity. About 5-15% of specimens resected for presumed Klatskin tumour prove not to be cholangiocarcinomas. There are a number of inflammatory, infective, vascular, and other pathologies, which have overlapping clinical and radiological features with a Klatskin tumour, leading to misinterpretation. This paper aims to summarise the features of such Klatskin-like lesions that have been reported in surgical literature.

[An Asian man with recurrent abdominal pain]

Recurrent pyogenic cholangitis (RPC), or oriental cholangiohepatitis, is characterized by intrabiliary pigment stone formation, whose main manifestation consists of recurrent episodes of cholangitis, although other biliopancreatic complications can also occur. RPC develops mainly in Asian patients, in whom this entity is one of the main causes of acute abdominal pain. The differential diagnosis should be established with all other entities associated with intrahepatic stone formation, which is more common in Asian countries compared with the predominance of gallstone formation in the West. The diagnostic and therapeutic approach requires collaboration among gastroenterologists, radiologists and gastrointestinal surgeons. We review the most important clinical, diagnostic and therapeutic features of this entity, which, although clearly predominant in Asia, is increasingly diagnosed in our setting.

MRCP and 3D LAVA imaging of extrahepatic cholangiocarcinoma at 3 T MRI

Extrahepatic cholangiocarcinoma (CCA) is a primary bile duct malignant tumour with poor prognosis. Familiarity with their varied imaging characteristics can be helpful in developing a correct diagnosis and in optimal treatment planning, and thus contribute to a better prognosis. The purpose of this article is to illustrate the typical appearances of extrahepatic CCA on magnetic resonance cholangiopancreatography (MRCP) and three-dimensional (3D) LAVA (liver acquisition with volume acceleration) sequences at 3 T magnetic resonance imaging (MRI), and to discuss the superiority of the two techniques in the diagnosis of CCA.

Magnetic resonance imaging of biliary tumors

This article presents current magnetic resonance imaging techniques for the diagnosis of biliary tumors. It emphasizes the need for a comprehensive protocol, combining imaging sequences of the liver parenchyma and soft tissues with magnetic resonance cholangiopancreatography and magnetic resonance angiography to detect and stage biliary malignancies. Imaging characteristics that may indicate a specific diagnosis are discussed. The potential role of diffusion-weighted imaging in diagnosing the cause of biliary obstruction and detecting unsuspected nodal disease and peritoneal seeding is emphasized and illustrated.

Results of a phase I-II study on intraductal confocal microscopy (IDCM) in patients with common bile duct (CBD) stenosis

BACKGROUND

Confocal endomicroscopy is an emergent technique and allows real optical biopsies in the gastrointestinal (GI) tract. The aim of this study was to evaluate a new intraductal confocal miniprobe in patients with a normal common bile duct (CBD) or with a suspicion of a malignant stenosis (cholangiocarcinoma).

METHODS

Thirty-seven patients (23 males) underwent endoscopic retrograde cholangiopancreatography (ERCP) for bile duct stone removal (7 cases) or bile duct stenosis (30 cases). Intraductal confocal microscopy (IDCM) was performed during the ERCP using a probe-based confocal laser endomicroscopy (pCLE) technique. IDCM was done with the CholangioFlex probe with Cellvizio (Mauna Kea Technologies, Paris, France). The depth of penetration of theCholangioFlex probe was 40-70 μm and magnification was 400×. Images were reviewed by an experienced pathologist in GI disease and compared to ERCP findings, CBD biopsies performed during ERCP or EUS, and in 15 patients to the resected specimen (Wipple resection).

RESULTS

No complications related to the CholangioFlex insertion occurred after the ERCP. Good images were obtained in 33 patients. Final histology diagnosis was a normal CBD in 7 cases, 23 malignant stenoses (4 ampullary carcinomas, 13 cholangiocarcinomas, and 6 pancreatic cancer), and 7 inflammatory stenoses (4 chronic pancreatitis, 1 stenosis of hepaticojejunal anastomosis, 1 postcholecystectomy CBD stenosis, and 1 primary sclerosing cholangitis). IDCM of a normal CBD showed a thin black band (<20 μm), normal vessels (thin and regular), and no visible glands. IDCM of malignant strictures revealed irregular vessels with lack of contrast in the CBD wall, large black band (>20 μm), and an aggregate of irregular black cells (black clumps). These aspects were seen in all malignant stenoses and none were seen in benign or normal CBD. The presence of irregular vessels, large black bands, and black clumps seen with confocal laser microscopy enabled prediction of neoplasia with an accuracy rate of 86%, sensitivity of 83%, and specificity of 75%. The respective numbers for standard histopathology were 53, 65, and 53%.

CONCLUSION

This phase I-II study on IDCM showed that IDCM is feasible. This new technique will open a new door for optical biopsy of the CBD.

Results of a phase I-II study on intraductal confocal microscopy (IDCM) in patients with common bile duct (CBD) stenosis

BACKGROUND

Confocal endomicroscopy is an emergent technique and allows real optical biopsies in the gastrointestinal (GI) tract. The aim of this study was to evaluate a new intraductal confocal miniprobe in patients with a normal common bile duct (CBD) or with a suspicion of a malignant stenosis (cholangiocarcinoma).

METHODS

Thirty-seven patients (23 males) underwent endoscopic retrograde cholangiopancreatography (ERCP) for bile duct stone removal (7 cases) or bile duct stenosis (30 cases). Intraductal confocal microscopy (IDCM) was performed during the ERCP using a probe-based confocal laser endomicroscopy (pCLE) technique. IDCM was done with the CholangioFlex probe with Cellvizio (Mauna Kea Technologies, Paris, France). The depth of penetration of theCholangioFlex probe was 40-70 μm and magnification was 400×. Images were reviewed by an experienced pathologist in GI disease and compared to ERCP findings, CBD biopsies performed during ERCP or EUS, and in 15 patients to the resected specimen (Wipple resection).

RESULTS

No complications related to the CholangioFlex insertion occurred after the ERCP. Good images were obtained in 33 patients. Final histology diagnosis was a normal CBD in 7 cases, 23 malignant stenoses (4 ampullary carcinomas, 13 cholangiocarcinomas, and 6 pancreatic cancer), and 7 inflammatory stenoses (4 chronic pancreatitis, 1 stenosis of hepaticojejunal anastomosis, 1 postcholecystectomy CBD stenosis, and 1 primary sclerosing cholangitis). IDCM of a normal CBD showed a thin black band (<20 μm), normal vessels (thin and regular), and no visible glands. IDCM of malignant strictures revealed irregular vessels with lack of contrast in the CBD wall, large black band (>20 μm), and an aggregate of irregular black cells (black clumps). These aspects were seen in all malignant stenoses and none were seen in benign or normal CBD. The presence of irregular vessels, large black bands, and black clumps seen with confocal laser microscopy enabled prediction of neoplasia with an accuracy rate of 86%, sensitivity of 83%, and specificity of 75%. The respective numbers for standard histopathology were 53, 65, and 53%.

CONCLUSION

This phase I-II study on IDCM showed that IDCM is feasible. This new technique will open a new door for optical biopsy of the CBD.

Primary hepatoid carcinoma of the biliary tree: a radiologic mimicker of Klatskin-type tumor

Hepatoid carcinomas are a group of neoplasms with features resembling hepatocellular carcinomas. Although extremely rare, more cases have been noted to arise from various organs within the last decade. Differentiating these tumors when located in the biliary tree from cholangiocarcinoma is not only a radiologic challenge but also critical, because treatment modalities and operative strategies are dependent on the exact nature of the tumor. We report a unique case in the literature of a 67-year-old Caucasian female who presented with obstructive jaundice due to an obstructing mass seen at the common hepatic duct on imaging with no preceding history of cirrhosis and increased serum α-fetoprotein (AFP), in whom a differential diagnosis from cholangiocarcinoma in a non-cirrhotic liver was particularly difficult given the combination of tumor location and solitary nature. The radiologist may include ectopic hepatoid adenocarcinomas in the differential consideration of an obstructing tumor in the biliary tree especially in patients with increased serum AFP levels.

Varying appearances of cholangiocarcinoma: radiologic-pathologic correlation

Intrahepatic cholangiocarcinoma is the second most common primary hepatic tumor. Various risk factors have been reported for intrahepatic cholangiocarcinoma, and the radiologic and pathologic findings of this disease entity may differ depending on the underlying risk factors. Intrahepatic cholangiocarcinoma can be classified into three types on the basis of gross morphologic features: mass-forming (the most common), periductal infiltrating, and intraductal growth. At computed tomography (CT), mass-forming intrahepatic cholangiocarcinoma usually appears as a homogeneous low-attenuation mass with irregular peripheral enhancement and can be accompanied by capsular retraction, satellite nodules, and peripheral intrahepatic duct dilatation. Periductal infiltrating cholangiocarcinoma is characterized by growth along the dilated or narrowed bile duct without mass formation. At CT and magnetic resonance imaging, diffuse periductal thickening and increased enhancement can be seen with a dilated or irregularly narrowed intrahepatic duct. Intraductal cholangiocarcinoma may manifest with various imaging patterns, including diffuse and marked ductectasia either with or without a grossly visible papillary mass, an intraductal polypoid mass within localized ductal dilatation, intraductal castlike lesions within a mildly dilated duct, and a focal stricture-like lesion with mild proximal ductal dilatation. Awareness of the underlying risk factors and morphologic characteristics of intrahepatic cholangiocarcinoma is important for accurate diagnosis and for differentiation from other hepatic tumorous and nontumorous lesions.

Sonazoid-enhanced ultrasonography for evaluation of the enhancement patterns of focal liver tumors in the late phase by intermittent imaging with a high mechanical index

OBJECTIVE

The purpose of this study was to evaluate the enhancement patterns of focal liver tumors in the late phase of Sonazoid-enhanced ultrasonography by intermittent imaging with a high mechanical index (MI).

METHODS

A total of 142 patients with 208 lesions, including 109 hepatocellular carcinomas (HCCs), 61 metastases, 30 hemangiomas, and 8 focal nodular hyperplasias (FNHs), were enrolled in this prospective study. Contrast-enhanced ultrasonography with intermittent scanning at 2 frames per second (MI, 0.7-1.2) was conducted in the late phase (>5 minutes after bolus intravenous injection of the perflubutane-based contrast agent Sonazoid; Daiichi Sankyo, Tokyo, Japan). Two blinded readers classified the enhancement patterns of the lesions. The sensitivity, specificity, and positive predictive value (PPV) of the dominant enhancement patterns and inter-reader agreement were assessed.

RESULTS

A combination of diffuse enhancement with intratumoral vessels and intratumoral vessels alone yielded sensitivity of 85% (average of both readers), specificity of 88%, and a PPV of 88% for HCC. For metastasis, a combination of peripheral ringlike enhancement with peritumoral vessels and peripheral ringlike enhancement with intratumoral vessels yielded sensitivity of 79%, specificity of 95%, and a PPV of 85%. For hemangiomas, a combination of peripheral nodular enhancement with peritumoral vessels and peripheral nodular enhancement without peritumoral vessels yielded sensitivity of 75%, specificity of 99%, and a PPV of 92%. Diffuse enhancement with spoked wheel arteries yielded sensitivity of 82%, specificity of 100%, and a PPV of 87% for FNHs. Good inter-reader agreement was achieved.

CONCLUSIONS

Sonazoid-enhanced ultrasonography using intermittent imaging with a high MI can potentially be used for evaluating the enhancement patterns of focal liver tumors in the late phase.

Mimics of cholangiocarcinoma: spectrum of disease

Cholangiocarcinoma is the second most common primary malignant hepatobiliary neoplasm, accounting for approximately 15% of liver cancers. Diagnosis of cholangiocarcinoma is challenging and the prognosis is uniformly poor, with recurrence rates of 60%-90% after surgical resection. A wide spectrum of neoplastic and nonneoplastic conditions of the biliary tract may masquerade as cholangiocarcinoma, adding to the complexity of management in patients suspected to have cholangiocarcinoma. Mimics of cholangiocarcinoma constitute a heterogeneous group of entities that includes primary sclerosing cholangitis, recurrent pyogenic cholangitis, acquired immunodeficiency syndrome cholangiopathy, autoimmune pancreatitis, inflammatory pseudotumor, Mirizzi syndrome, xanthogranulomatous cholangitis, sarcoidosis, chemotherapy-induced sclerosis, hepatocellular carcinoma, metastases, melanoma, lymphoma, leukemia, and carcinoid tumors. These entities demonstrate characteristic histomorphology and variable clinicobiologic behaviors. The imaging findings of these disparate entities are protean and may be indistinguishable from those of cholangiocarcinoma. In most cases, a definitive diagnosis can be established only with histopathologic examination of a biopsy specimen.

Magnetic resonance imaging of liver lesions: exceptions and atypical lesions

On state-of-the-art magnetic resonance imaging, most lesions can be detected and characterized with confidence according to well-known criteria. However, atypical characteristics in some common lesions and the incidental encounter with rare lesions may pose diagnostic difficulties. In this article, six challenging hepatic lesions will be discussed and evaluated on the most important magnetic resonance imaging sequences, with histological correlation when available. In addition, the background information concerning these lesions will be described based on the most recent available literature. By reading this article, the reader will be able to (1) categorize the lesion in solid and fluid-containing lesions, based on the T2 signal intensity; and (2) define the benign or malignant nature of the lesion, in relation to the signal intensity and dynamic enhancement pattern, despite the presence of atypical characteristics of some lesions.

Obstructive jaundice in polycystic liver disease related to coexisting cholangiocarcinoma

Although jaundice rarely complicates polycystic liver disease (PLD), secondary benign or malignant causes cannot be excluded. In a 72-year-old female who presented with increased abdominal girth, dyspnea, weight loss and jaundice, ultrasound and computed tomography confirmed the diagnosis of PLD by demonstrating large liver cysts causing extrahepatic bile duct compression. Percutaneous cyst aspiration failed to relief jaundice due to distal bile duct cholangiocarcinoma, suspected by magnetic resonance cholangiopancreatography (MRCP) and confirmed by endoscopic retrograde cholangiopancreatography (ERCP). Coexistence of PLD with distal common bile duct cholangiocarcinoma has not been reported so far.

Diagnosis of cholangiocarcinoma

Cholangiocarcinoma is suspected based on signs of biliary obstruction, abnormal liver function tests, elevated tumor markers (carbohydrate antigen 19-9 and carcinoembryonic antigen), and ultrasonography showing a bile stricture or a mass, especially in intrahepatic cholangiocarcinoma. Magnetic resonance imaging (MRI) or computed tomography (CT) is performed for the diagnosis and staging of cholangiocarcinomas. However, differentiation of an intraductal cholangiocarcinoma from a hypovascular metastasis is limited at imaging. Therefore, reasonable exclusion of an extrahepatic primary tumor should be performed. Differentiating between benign and malignant bile duct stricture is also difficult, except when metastases are observed. The sensitivity of fluorodeoxyglucose positron emission tomography is limited in small, infiltrative, and mucinous cholangiocarcinomas. When the diagnosis of a biliary stenosis remains indeterminate at MRI or CT, endoscopic imaging (endoscopic or intraductal ultrasound, cholangioscopy, or optical coherence tomography) and tissue sampling should be carried out. Tissue sampling has a high specificity for diagnosing malignant biliary strictures, but sensitivity is low. The diagnosis of cholangiocarcinoma is particularly challenging in patients with primary sclerosing cholangitis. These patients should be followed with yearly tumor markers, CT, or MRI. In the case of dominant stricture, histological or cytological confirmation of cholangiocarcinoma should be obtained. More studies are needed to compare the accuracy of the various imaging methods, especially the new intraductal methods, and the imaging features of malignancy should be standardized.

Magnetic resonance imaging of liver malignancies

The histological structure of the liver is complex, consisting of hepatocytes, biliary epithelium, and mesenchymal cells. From this large variety of cells, a broad spectrum of benign and malignant liver lesions in originate. An accurate diagnosis of these lesions is mandatory for choosing an appropriate therapeutic approach. With the recent developments in hardware and software, magnetic resonance imaging (MRI) has emerged as the method of choice in the diagnostic workup of focal liver lesions, in particular in the pretherapeutic stage. The introduction of high-field MRI at 3.0 T in the routine workup and the selective use of liver-specific contrast agents, including hepatobiliary and reticuloendothelial agents, have also strengthened the role of MRI in liver imaging. In this overview article, we will review the recent developments in 3.0-T MRI and MRI contrast agents in the diagnostic workup of the most common malignant liver tumors.