(Radiographics. 2001;21:S97-S116.)
© RSNA, 2001
Helping the Hepatic Surgeon |
Radiologic Spectrum of Cholangiocarcinoma: Emphasis on Unusual Manifestations and Differential Diagnoses1
Won J. Lee, MD,
Hyo K. Lim, MD,
Kyung M. Jang, MD,
Seung H. Kim, MD,
Soon J. Lee, MD,
Jae H. Lim, MD and
In W. Choo, MD
1 From the Department of Radiology and Gastrointestinal Center, Samsung Medical Center, Sungkyunkwan University School of Medicine, 50 Ilwon-Dong, Kangnam-Ku, Seoul 135-710, South Korea. Recipient of a Certificate of Merit award for an education exhibit at the 2000 RSNA scientific assembly. Received February 6, 2001; revision requested March 5 and received June 7; accepted June 21. Address correspondence to H.K.L. (e-mail: hklim@smc.samsung.co.kr).
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Abstract
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Most cholangiocarcinomas are ductal adenocarcinomas that arise from both intra- and extrahepatic bile duct epithelium, and their typical growth pattern can be classified as exophytic, infiltrative, polypoid, or a combination of these. Those of unusual histologic type (eg, mucin-hypersecreting cholangiocarcinoma, squamous adenocarcinoma, biliary cystadenocarcinoma, and mucinous carcinoma) show a growth pattern different from that of the typical ones (ie, ductal). Cholangiocarcinomas frequently develop in patients with any of a variety of preexisting bile duct diseases, some of which are considered precursors of cholangiocarcinoma (eg, biliary lithiasis, clonorchiasis, recurrent pyogenic cholangitis, and primary sclerosing cholangitis). Some bulky hepatic tumors of either primary or secondary origin mimic exophytic peripheral cholangiocarcinoma. Some variants of hepatocellular carcinoma, such as sclerosing, fibrolamellar, and cholangiohepatocellular carcinoma, resemble exophytic peripheral cholangiocarcinoma, while that with intraductal growth resembles polypoid cholangiocarcinoma. Among benign bile duct diseases, tumorous conditions (eg, benign biliary tumors) may mimic polypoid cholangiocarcinoma, whereas benign stricture of various causes (eg, cholangitides, traumatic and postsurgical sequelae, chronic pancreatitis, papillary stenosis) usually mimics infiltrative cholangiocarcinoma.
Index Terms: Bile ducts, CT, 76.12114 • Bile ducts, diseases, 76.288 • Bile ducts, neoplasms, 76.321 • Bile ducts, US • Liver neoplasms, diagnosis
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LEARNING OBJECTIVES FOR TEST 3
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After reading this article and taking the test, the reader will be able to:
- Describe typical growth patterns of both intra- and extrahepatic cholangiocarcinoma and their radiologic findings.
- Describe unusual manifestations of cholangiocarcinoma and their radiologic findings.
- Describe various hepatobiliary diseases that mimic cholangiocarcinoma.
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Introduction
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Cholangiocarcinoma is a biliary carcinoma that arises from the intra- and extrahepatic bile ducts and manifests with various histologic types and growth patterns. Accordingly, cholangiocarcinoma has a wide spectrum of radiologic appearances that may overlap with those of other hepatobiliary diseases, including benign varieties. In this respect, knowledge of various radiologic manifestations of cholangiocarcinoma as well as its mimickers is helpful in the diagnosis and differentiation of cholangiocarcinoma. Some biliary diseases are known to be risk factors for cholangiocarcinoma. In these cases, it is important to recognize the development of cholangiocarcinoma at imaging studies. In this article, we describe the radiologic findings of a wide spectrum of cholangiocarcinoma, with an emphasis on unusual manifestations and differential diagnoses.
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Classification
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Cholangiocarcinoma may arise at any portion of the bile duct epithelium, that is, from the terminal ductules (canals of Hering) to the ampulla of Vater, as well as at the peribiliary glands (intramural and extramural) (1,2). Therefore, it may be classified as intrahepatic or extrahepatic, and intrahepatic cholangiocarcinoma is subdivided into peripheral or hilar on the basis of its site of origin (1,3). Though their precise definitions are controversial, peripheral cholangiocarcinoma is widely believed to originate from the intrahepatic bile ducts (ie, bile ducts distal to second-order branches), while hilar cholangiocarcinoma (Klatskin tumor) originates from the right and left hepatic ducts (ie, first-order branches of the bile duct) and the bifurcation of both hepatic ducts (1–6).
Clinical symptoms of hilar cholangiocarcinoma are more like those of the extrahepatic kind (eg, obstructive jaundice) than those of the peripheral variety (eg, abdominal pain, weight loss) (2). On the other hand, peripheral cholangiocarcinoma can spread continuously into the hepatic hilum, whereas hilar cholangiocarcinoma often shows continuous infiltration to the intrahepatic bile ducts (1). In these cases, differentiation between hilar and peripheral cholangiocarcinomas is difficult. Moreover, hilar cholangiocarcinoma is treated according to the same principles used for peripheral (eg, resection with or without radiation therapy, or palliative care) rather than extrahepatic (eg, resection with or without radiation therapy) (7). In this respect, it is reasonable that hilar cholangiocarcinoma is classified as intrahepatic, even though the right and left hepatic ducts join outside the liver anatomically.
Various histologic types of cholangiocarcinoma are seen at microscopy: ductal (well, moderately, or poorly differentiated), papillary, mucinous, signet-ring cell, mucoepidermoid, adenosquamous, squamous, and cystadenocarcinoma (1,8). Most intra- and extrahepatic cholangiocarcinomas are ductal adenocarcinomas (1,8).
On the macroscopic level, intra- and extrahepatic cholangiocarcinomas are usually categorized into three types by their growth patterns: exophytic (mass-forming), infiltrative (periductal), and polypoid (intraductal) (6,9–13). Some literature has reported that two growth patterns could be admixed in a cholangiocarcinoma: thus, the combined type (6,14). Therefore, the typical growth pattern of both intra- and extrahepatic cholangiocarcinomas can be further divided into four types (Fig 1).
Exophytic Cholangiocarcinoma
The most common type of peripheral cholangiocarcinoma (Fig 2) (15), exophytic cholangiocarcinoma, infrequently arises from a hilar (9,10, 13) or extrahepatic location (Fig 3) (11). The histologic appearance of exophytic peripheral cholangiocarcinoma is usually that of an undifferentiated or poorly differentiated ductal adenocarcinoma that grows expansively beyond the bile duct wall and frequently contains mucin and microcystic necrotic material (4,5).
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Figure 2a. Exophytic peripheral cholangiocarcinoma in a 48-year-old man with abdominal pain. Arterial- (a) and equilibrium-phase (b) computed tomographic (CT) scans show a large, hypoattenuating mass with lobulated margins (arrows) in the right hepatic lobe. Thin, rimlike contrast enhancement around the tumor at the arterial phase and concentric filling of contrast material at the equilibrium phase are typical appearances of this type of cholangiocarcinoma.
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Figure 2b. Exophytic peripheral cholangiocarcinoma in a 48-year-old man with abdominal pain. Arterial- (a) and equilibrium-phase (b) computed tomographic (CT) scans show a large, hypoattenuating mass with lobulated margins (arrows) in the right hepatic lobe. Thin, rimlike contrast enhancement around the tumor at the arterial phase and concentric filling of contrast material at the equilibrium phase are typical appearances of this type of cholangiocarcinoma.
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Figure 3a. Exophytic extrahepatic cholangiocarcinoma in a 56-year-old man with weight loss. (a) Oblique sonogram shows a polypoid mass (arrows) that obstructs the lumen in the distal part of the common bile duct. (b) Cholangiogram shows a focal, eccentric filling defect (arrows) in the distal part of the common bile duct. (c) Photograph of the resected specimen shows a protruding mass (arrows) in the distal part of the common bile duct. Most of this tumor formed an exophytic mass that grew outwardly from the bile duct wall.
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Figure 3b. Exophytic extrahepatic cholangiocarcinoma in a 56-year-old man with weight loss. (a) Oblique sonogram shows a polypoid mass (arrows) that obstructs the lumen in the distal part of the common bile duct. (b) Cholangiogram shows a focal, eccentric filling defect (arrows) in the distal part of the common bile duct. (c) Photograph of the resected specimen shows a protruding mass (arrows) in the distal part of the common bile duct. Most of this tumor formed an exophytic mass that grew outwardly from the bile duct wall.
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Figure 3c. Exophytic extrahepatic cholangiocarcinoma in a 56-year-old man with weight loss. (a) Oblique sonogram shows a polypoid mass (arrows) that obstructs the lumen in the distal part of the common bile duct. (b) Cholangiogram shows a focal, eccentric filling defect (arrows) in the distal part of the common bile duct. (c) Photograph of the resected specimen shows a protruding mass (arrows) in the distal part of the common bile duct. Most of this tumor formed an exophytic mass that grew outwardly from the bile duct wall.
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At CT, the typical appearance of exophytic peripheral cholangiocarcinoma is a large, irregular, hypoattenuating mass with stippled or punctate, hyperattenuating foci within the tumor (Fig 2) (3–5). At dynamic CT and magnetic resonance (MR) imaging, thin, rimlike or thick, bandlike contrast enhancement around the tumor is seen at the early phase, with progressive and concentric filling of contrast material at the later phase (Fig 2) (3,14,16,17). This phenomenon is explained by slow diffusion into the interstitial spaces of the tumor (18). A fibrotic component within this type of cholangiocarcinoma also contributes to the delayed tumoral contrast enhancement (19).
Infiltrative Cholangiocarcinoma
Infiltrative cholangiocarcinoma is the most common type of hilar and extrahepatic cholangiocarcinoma (9–11). At histologic examination, this type shows infiltrative growth by a scirrhous adenocarcinoma and is usually an undifferentiated or a poorly differentiated ductal adenocarcinoma (9,20).
At thin-section CT, ill-defined, infiltrating tumor tissue of this type can be detected as focal wall thickening, usually with early or late enhancement, or both (Fig 4) (10,13). At ultrasonography (US), it appears as a mural thickening or encircling mass along the bile duct wall (11). This type is also frequently seen as nonunion of the dilated right and left hepatic ducts without an identifiable mass at either US or CT (10,20). Cholangiography shows focal or diffuse stricture or complete obstruction of the bile ducts and thus allows determination of the extent of disease (Fig 4) (9,12,20).
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Figure 4a. Infiltrative hilar cholangiocarcinoma in a 59-year-old woman with progressive jaundice. (a) Arterial-phase CT scan shows a well-enhancing, thickened bile duct wall (arrows) at the hepatic hilar level. (b) Cholangiogram shows complete obstruction at the hepatic hilar level and severe strictures (arrows) that involve both hepatic ducts.
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Figure 4b. Infiltrative hilar cholangiocarcinoma in a 59-year-old woman with progressive jaundice. (a) Arterial-phase CT scan shows a well-enhancing, thickened bile duct wall (arrows) at the hepatic hilar level. (b) Cholangiogram shows complete obstruction at the hepatic hilar level and severe strictures (arrows) that involve both hepatic ducts.
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Polypoid Cholangiocarcinoma
Polypoid cholangiocarcinoma is infrequently found in both the intra- and extrahepatic ducts. The histologic type of this tumor is mostly papillary adenocarcinoma that shows intraluminal growth (7,21,22). The tumor is depicted as an intraluminal polypoid mass at both US and CT (9–11,13) and as a polypoid filling defect at cholangiography (Fig 5) (9,12,20).
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Figure 5a. Polypoid extrahepatic cholangiocarcinoma in a 45-year-old man with jaundice. (a) Portal-phase CT scan shows a polypoid mass (arrows) within the dilated proximal portion of the common bile duct. (b) Transverse sonogram shows a polypoid mass (arrows) obstructing the dilated proximal portion of the common bile duct. (c) Cholangiogram shows an irregular filling defect (arrows) involving the proximal and middle portions of the common bile duct. The histologic type of this tumor was proved to be papillary cholangiocarcinoma.
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Figure 5b. Polypoid extrahepatic cholangiocarcinoma in a 45-year-old man with jaundice. (a) Portal-phase CT scan shows a polypoid mass (arrows) within the dilated proximal portion of the common bile duct. (b) Transverse sonogram shows a polypoid mass (arrows) obstructing the dilated proximal portion of the common bile duct. (c) Cholangiogram shows an irregular filling defect (arrows) involving the proximal and middle portions of the common bile duct. The histologic type of this tumor was proved to be papillary cholangiocarcinoma.
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Figure 5c. Polypoid extrahepatic cholangiocarcinoma in a 45-year-old man with jaundice. (a) Portal-phase CT scan shows a polypoid mass (arrows) within the dilated proximal portion of the common bile duct. (b) Transverse sonogram shows a polypoid mass (arrows) obstructing the dilated proximal portion of the common bile duct. (c) Cholangiogram shows an irregular filling defect (arrows) involving the proximal and middle portions of the common bile duct. The histologic type of this tumor was proved to be papillary cholangiocarcinoma.
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Combined Cholangiocarcinoma
Though few articles have described combined cholangiocarcinoma (6,14), the combined growth pattern is commonly encountered in intrahepatic cholangiocarcinoma. Occasionally, it is difficult to differentiate infiltrative hilar cholangiocarcinoma that grows expansively into the liver parenchyma (Fig 6) from the exophytic peripheral type that invades centrally into the hepatic hilum (Fig 7) (9,10). In cases of combined cholangiocarcinoma near the hepatic hilum, therefore, it is necessary to clarify the extent of both the exophytic and the infiltrative components with the use of various imaging studies to determine proper treatment.
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Figure 6a. Combined hilar cholangiocarcinoma in a 65-year-old man with right upper quadrant abdominal pain and jaundice. (a) Portal-phase CT scan obtained at the hepatic hilar level shows an ill-defined, hypoattenuating mass (arrows) adjacent to the hepatic hilum (ie, exophytic hilar cholangiocarcinoma) and dilatation of both intrahepatic bile ducts. Thickening of the bile duct wall (arrowheads) is shown adjacent to the exophytic mass (ie, infiltrative cholangiocarcinoma). (b) Portal-phase CT scan obtained at the level of the proximal portion of the common bile duct shows an irregular thickening of the bile duct wall (arrows) (ie, infiltrative cholangiocarcinoma). (c) Cholangiogram shows complete obstruction of the hepatic hilum and both hepatic ducts. There is severe stricture of the intrahepatic bile duct of the anterior segment of the right hepatic lobe (arrows). (d) Cholangiogram shows complete obstruction of the hepatic hilum, proximal portion of the common bile duct, and segmental bile ducts of the right hepatic lobe. Irregular and severe strictures (arrows) exist at both the proximal portion of the common bile duct and the intrahepatic bile duct of the anterior segment of the right hepatic lobe (arrowheads). The left hepatic duct is not opacified.
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Figure 6b. Combined hilar cholangiocarcinoma in a 65-year-old man with right upper quadrant abdominal pain and jaundice. (a) Portal-phase CT scan obtained at the hepatic hilar level shows an ill-defined, hypoattenuating mass (arrows) adjacent to the hepatic hilum (ie, exophytic hilar cholangiocarcinoma) and dilatation of both intrahepatic bile ducts. Thickening of the bile duct wall (arrowheads) is shown adjacent to the exophytic mass (ie, infiltrative cholangiocarcinoma). (b) Portal-phase CT scan obtained at the level of the proximal portion of the common bile duct shows an irregular thickening of the bile duct wall (arrows) (ie, infiltrative cholangiocarcinoma). (c) Cholangiogram shows complete obstruction of the hepatic hilum and both hepatic ducts. There is severe stricture of the intrahepatic bile duct of the anterior segment of the right hepatic lobe (arrows). (d) Cholangiogram shows complete obstruction of the hepatic hilum, proximal portion of the common bile duct, and segmental bile ducts of the right hepatic lobe. Irregular and severe strictures (arrows) exist at both the proximal portion of the common bile duct and the intrahepatic bile duct of the anterior segment of the right hepatic lobe (arrowheads). The left hepatic duct is not opacified.
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Figure 6c. Combined hilar cholangiocarcinoma in a 65-year-old man with right upper quadrant abdominal pain and jaundice. (a) Portal-phase CT scan obtained at the hepatic hilar level shows an ill-defined, hypoattenuating mass (arrows) adjacent to the hepatic hilum (ie, exophytic hilar cholangiocarcinoma) and dilatation of both intrahepatic bile ducts. Thickening of the bile duct wall (arrowheads) is shown adjacent to the exophytic mass (ie, infiltrative cholangiocarcinoma). (b) Portal-phase CT scan obtained at the level of the proximal portion of the common bile duct shows an irregular thickening of the bile duct wall (arrows) (ie, infiltrative cholangiocarcinoma). (c) Cholangiogram shows complete obstruction of the hepatic hilum and both hepatic ducts. There is severe stricture of the intrahepatic bile duct of the anterior segment of the right hepatic lobe (arrows). (d) Cholangiogram shows complete obstruction of the hepatic hilum, proximal portion of the common bile duct, and segmental bile ducts of the right hepatic lobe. Irregular and severe strictures (arrows) exist at both the proximal portion of the common bile duct and the intrahepatic bile duct of the anterior segment of the right hepatic lobe (arrowheads). The left hepatic duct is not opacified.
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Figure 6d. Combined hilar cholangiocarcinoma in a 65-year-old man with right upper quadrant abdominal pain and jaundice. (a) Portal-phase CT scan obtained at the hepatic hilar level shows an ill-defined, hypoattenuating mass (arrows) adjacent to the hepatic hilum (ie, exophytic hilar cholangiocarcinoma) and dilatation of both intrahepatic bile ducts. Thickening of the bile duct wall (arrowheads) is shown adjacent to the exophytic mass (ie, infiltrative cholangiocarcinoma). (b) Portal-phase CT scan obtained at the level of the proximal portion of the common bile duct shows an irregular thickening of the bile duct wall (arrows) (ie, infiltrative cholangiocarcinoma). (c) Cholangiogram shows complete obstruction of the hepatic hilum and both hepatic ducts. There is severe stricture of the intrahepatic bile duct of the anterior segment of the right hepatic lobe (arrows). (d) Cholangiogram shows complete obstruction of the hepatic hilum, proximal portion of the common bile duct, and segmental bile ducts of the right hepatic lobe. Irregular and severe strictures (arrows) exist at both the proximal portion of the common bile duct and the intrahepatic bile duct of the anterior segment of the right hepatic lobe (arrowheads). The left hepatic duct is not opacified.
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Figure 7a. Combined peripheral cholangiocarcinoma in a 69-year-old woman with abdominal pain. (a) Equilibrium-phase CT scan shows a round, hypoattenuating mass (arrows) in the posterior segment of the right hepatic lobe (ie, exophytic peripheral cholangiocarcinoma) and dilatation of the adjacent intrahepatic bile duct of the posterior segment of the right hepatic lobe. There is concentric thickening of the proximal portion of the common bile duct (arrowheads) (ie, infiltrative cholangiocarcinoma). (b) Cholangiogram shows obstruction of the posterior segment bile ducts of the right hepatic lobe and mild stricture of the right hepatic duct extending to the proximal common bile duct (arrows) (ie, infiltrative cholangiocarcinoma).
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Figure 7b. Combined peripheral cholangiocarcinoma in a 69-year-old woman with abdominal pain. (a) Equilibrium-phase CT scan shows a round, hypoattenuating mass (arrows) in the posterior segment of the right hepatic lobe (ie, exophytic peripheral cholangiocarcinoma) and dilatation of the adjacent intrahepatic bile duct of the posterior segment of the right hepatic lobe. There is concentric thickening of the proximal portion of the common bile duct (arrowheads) (ie, infiltrative cholangiocarcinoma). (b) Cholangiogram shows obstruction of the posterior segment bile ducts of the right hepatic lobe and mild stricture of the right hepatic duct extending to the proximal common bile duct (arrows) (ie, infiltrative cholangiocarcinoma).
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Unusual Manifestations
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Cholangiocarcinomas of an Unusual Histologic Type
Most cholangiocarcinomas are ductal, regardless of their location, and their radiologic manifestations are described above. Some of an unusual histologic type, however, show their peculiar growth pattern as their characteristic radiologic feature.
Mucin-hypersecreting Cholangiocarcinoma.—
Cholangiocarcinoma produces variable amounts of mucin, which is retained in the tumor in most cases. In rare instances, however, two histologic types of cholangiocarcinoma (papillary and biliary) can produce so much mucin that it enters the bile duct, resulting in bile stasis and obstructive jaundice (23).
Most papillary cholangiocarcinomas are peripheral in location and massive, nodular, or papillary in shape (22–24). At imaging, the primary tumor may be depicted as an intraluminal, polypoid lesion (ie, polypoid cholangiocarcinoma) (Figs 5, 8) or may not be depicted when it is small (<1 cm in diameter) or spreads along a mucosal membrane (4,14,22–24). When papillary cholangiocarcinoma produces excessive mucin, US and CT show severe and diffuse dilatation of the intra- and extrahepatic ducts both proximal to and distal from the responsible tumor (Fig 8) (14,22–24). Crowding of the dilated intrahepatic ducts at US and CT can be seen as a cystic mass that mimics hepatic abscess, necrotic cholangiocarcinoma, biliary cystadenoma or cystadenocarcinoma, or ruptured hydatid cyst (14). Massive amounts of mucin within the dilated bile ducts can be seen as large, amorphous filling defects at cholangiography (14,23). Various conditions are manifest as filling defects in the dilated bile ducts and include stones, air bubbles, blood clots, and intraluminal tumors (23).
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Figure 8a. Mucin-hypersecreting intraductal papillary cholangiocarcinoma in a 48-year-old woman with indigestion. (a-c) Portal-phase CT scan (a), T1-weighted transverse MR image (b), and T2-weighted coronal MR image (c) show marked dilatation of the intrahepatic bile ducts (arrows) in the lateral segment of the left hepatic lobe. An intraluminal polypoid nodule (arrowheads) appears on the anterior surface of the most prominently dilated intrahepatic bile duct. (d) MR cholangiogram shows marked dilatation of the intrahepatic bile ducts of the left lateral segment, left hepatic duct, and extrahepatic bile duct (arrows). The nodule on the anterior surface is not clearly shown. (e) Photograph of the resected specimen shows the dilated intrahepatic bile ducts (arrows) of the left lateral segment. These intrahepatic bile ducts were shown to communicate with the left hepatic duct at resection. At microscopy, malignant foci were detected in the adenomatous nodule without invasion of the periductal space. Dysplastic epithelial cells were shown to spread along the mucosal surface of the intrahepatic bile ducts.
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Figure 8b. Mucin-hypersecreting intraductal papillary cholangiocarcinoma in a 48-year-old woman with indigestion. (a-c) Portal-phase CT scan (a), T1-weighted transverse MR image (b), and T2-weighted coronal MR image (c) show marked dilatation of the intrahepatic bile ducts (arrows) in the lateral segment of the left hepatic lobe. An intraluminal polypoid nodule (arrowheads) appears on the anterior surface of the most prominently dilated intrahepatic bile duct. (d) MR cholangiogram shows marked dilatation of the intrahepatic bile ducts of the left lateral segment, left hepatic duct, and extrahepatic bile duct (arrows). The nodule on the anterior surface is not clearly shown. (e) Photograph of the resected specimen shows the dilated intrahepatic bile ducts (arrows) of the left lateral segment. These intrahepatic bile ducts were shown to communicate with the left hepatic duct at resection. At microscopy, malignant foci were detected in the adenomatous nodule without invasion of the periductal space. Dysplastic epithelial cells were shown to spread along the mucosal surface of the intrahepatic bile ducts.
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Figure 8c. Mucin-hypersecreting intraductal papillary cholangiocarcinoma in a 48-year-old woman with indigestion. (a-c) Portal-phase CT scan (a), T1-weighted transverse MR image (b), and T2-weighted coronal MR image (c) show marked dilatation of the intrahepatic bile ducts (arrows) in the lateral segment of the left hepatic lobe. An intraluminal polypoid nodule (arrowheads) appears on the anterior surface of the most prominently dilated intrahepatic bile duct. (d) MR cholangiogram shows marked dilatation of the intrahepatic bile ducts of the left lateral segment, left hepatic duct, and extrahepatic bile duct (arrows). The nodule on the anterior surface is not clearly shown. (e) Photograph of the resected specimen shows the dilated intrahepatic bile ducts (arrows) of the left lateral segment. These intrahepatic bile ducts were shown to communicate with the left hepatic duct at resection. At microscopy, malignant foci were detected in the adenomatous nodule without invasion of the periductal space. Dysplastic epithelial cells were shown to spread along the mucosal surface of the intrahepatic bile ducts.
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Figure 8d. Mucin-hypersecreting intraductal papillary cholangiocarcinoma in a 48-year-old woman with indigestion. (a-c) Portal-phase CT scan (a), T1-weighted transverse MR image (b), and T2-weighted coronal MR image (c) show marked dilatation of the intrahepatic bile ducts (arrows) in the lateral segment of the left hepatic lobe. An intraluminal polypoid nodule (arrowheads) appears on the anterior surface of the most prominently dilated intrahepatic bile duct. (d) MR cholangiogram shows marked dilatation of the intrahepatic bile ducts of the left lateral segment, left hepatic duct, and extrahepatic bile duct (arrows). The nodule on the anterior surface is not clearly shown. (e) Photograph of the resected specimen shows the dilated intrahepatic bile ducts (arrows) of the left lateral segment. These intrahepatic bile ducts were shown to communicate with the left hepatic duct at resection. At microscopy, malignant foci were detected in the adenomatous nodule without invasion of the periductal space. Dysplastic epithelial cells were shown to spread along the mucosal surface of the intrahepatic bile ducts.
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Figure 8e. Mucin-hypersecreting intraductal papillary cholangiocarcinoma in a 48-year-old woman with indigestion. (a-c) Portal-phase CT scan (a), T1-weighted transverse MR image (b), and T2-weighted coronal MR image (c) show marked dilatation of the intrahepatic bile ducts (arrows) in the lateral segment of the left hepatic lobe. An intraluminal polypoid nodule (arrowheads) appears on the anterior surface of the most prominently dilated intrahepatic bile duct. (d) MR cholangiogram shows marked dilatation of the intrahepatic bile ducts of the left lateral segment, left hepatic duct, and extrahepatic bile duct (arrows). The nodule on the anterior surface is not clearly shown. (e) Photograph of the resected specimen shows the dilated intrahepatic bile ducts (arrows) of the left lateral segment. These intrahepatic bile ducts were shown to communicate with the left hepatic duct at resection. At microscopy, malignant foci were detected in the adenomatous nodule without invasion of the periductal space. Dysplastic epithelial cells were shown to spread along the mucosal surface of the intrahepatic bile ducts.
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In biliary cystadenocarcinoma, cystic tumor tissue usually contains the excessive mucin and infrequently communicates with a bile duct. Therefore, marked dilatation of the bile duct is uncommon. At imaging, both biliary cystadenoma and cystadenocarcinoma are manifest as a unilocular or multilocular cystic mass. Biliary cystadenocarcinoma, however, shows more complicated features (eg, papillary excrescences, nodular thickening, mural nodules) within a cystic tumor (Fig 9) (25).
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Figure 9a. Biliary cystadenocarcinoma in a 65-year-old woman with abdominal pain. Arterial- (a) and equilibrium-phase (b) CT scans show a large, bilobular, cystic mass with internal septation and calcification (arrows) that involves the left hepatic lobe. Papillary excrescences and mural nodules along the cyst wall enhance well during the arterial phase.
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Figure 9b. Biliary cystadenocarcinoma in a 65-year-old woman with abdominal pain. Arterial- (a) and equilibrium-phase (b) CT scans show a large, bilobular, cystic mass with internal septation and calcification (arrows) that involves the left hepatic lobe. Papillary excrescences and mural nodules along the cyst wall enhance well during the arterial phase.
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Mucinous carcinoma is the rarest of the histologic types, and its radiologic characteristics are reported to be large mucinous lakes throughout the tumor without mucin excretion into the bile duct (26).
Squamous Cell Carcinoma.—
Squamous cell carcinoma never occurs in the liver by itself, and therefore the occurrence of a squamous element has been interpreted to be a result of metaplastic transformation of adenocarcinoma cells. In this respect, squamous cell carcinoma is considered to be adenocarcinoma that is entirely replaced by a squamous element and thus prone to develop into an advanced stage of cholangiocarcinoma, as indicated by the large tumor size and aggressive intrahepatic spreading (Fig 10) (1).
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Figure 10a. Squamous cell carcinoma in a 71-year-old man with right upper quadrant abdominal pain. Arterial- (a) and equilibrium-phase (b) CT scans show a large irregular, hypoattenuating mass (arrows) in the right hepatic lobe. The thick, bandlike hypoattenuating area around the tumor periphery during the arterial phase is progressively filled with contrast material during the equilibrium phase. This finding resembles the contrast enhancement pattern of cholangiocarcinoma.
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Figure 10b. Squamous cell carcinoma in a 71-year-old man with right upper quadrant abdominal pain. Arterial- (a) and equilibrium-phase (b) CT scans show a large irregular, hypoattenuating mass (arrows) in the right hepatic lobe. The thick, bandlike hypoattenuating area around the tumor periphery during the arterial phase is progressively filled with contrast material during the equilibrium phase. This finding resembles the contrast enhancement pattern of cholangiocarcinoma.
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Cholangiocarcinoma Arising from Preexisting Bile Duct Diseases
The occurrence of cholangiocarcinoma is associated with such preexisting bile duct diseases as biliary lithiasis, clonorchiasis, recurrent pyogenic cholangitis, primary sclerosing cholangitis, congenital hepatic cyst, choledochal cyst, benign biliary tumors, exposure to thalium oxide, and choledochoenteric anastomosis (1,2,5,12,20,21), and the so-called ductal plate malformation (eg, biliary hamartoma, polycystic disease, congenital hepatic fibrosis, Caroli disease) (1,2).
Among types of biliary lithiasis, cholelithiasis (gallstone) is known to occur more frequently in patients with cholangiocarcinoma than in the general population, but the relationship remains obscure (1,2). Intrahepatic lithiasis is associated with cholangiocarcinoma in 5%–10% of cases (1,27). Moreover, intrahepatic lithiasis is closely correlated with clonorchiasis and recurrent pyogenic cholangitis, all of which are generally accepted to be important causes of cholangiocarcinoma (2,28–31).
Primary sclerosing cholangitis is also a well-known precursor of cholangiocarcinoma (1,2, 20,32). At imaging, cholangiocarcinoma as a complication of primary sclerosing cholangitis should be suspected when a polypoid mass, progressive or marked dilatation of the bile duct, a thickened bile duct wall, or dominant ductal stricture is detected (32).
Clonorchiasis.—
Clonorchiasis is a chronic infestation of the liver fluke Clonorchis sinensis, and its endemic area is largely confined to Southeast Asia. In this area, clonorchiasis is considered an important cause of recurrent pyogenic cholangitis and cholangiocarcinoma (29).
Characteristic radiologic findings of clonorchiasis associated with cholangiocarcinoma are diffuse and uniform dilatation of the peripheral intrahepatic ducts without significant dilatation of the extrahepatic duct and focal obstructing lesion (Fig 11) (29). The fluke can be shown as a non-shadowing echogenic focus or cast at US, and the bile ducts often appear to be diffusely thickened at both US and CT (29). All types of carcinomatous growth pattern are found in patients with clonorchiasis and cholangiocarcinoma (4,10,22).
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Figure 11. Cholangiocarcinoma in a 56-year-old man with clonorchiasis. Portal-phase CT scan shows a large, hypoattenuating mass (arrows) in the right hepatic lobe. There is minimal and uniform dilatation of the peripheral intrahepatic bile ducts (arrowheads). Liver flukes (Clonorchis sinensis) were found at surgery.
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Recurrent Pyogenic Cholangitis.—
Recurrent pyogenic cholangitis (oriental cholangiohepatitis or intrahepatic pigmented stone disease) is also a disease endemic to Southeast Asia (28,30). It is believed that clonorchiasis causes recurrent pyogenic cholangitis by acting as a nidus for stone formation, which predisposes a patient to stasis and secondary bacterial infection, or by damaging the bile ducts, which leads to strictures and resultant stone formation (28,30).
US and CT findings encompass intra- and extrahepatic lithiases, severe dilatation of the extra-hepatic bile duct with relatively mild or no dilatation of intrahepatic bile ducts, isolated lobar or segmental dilatation of the bile ducts, lobar or segmental atrophy, stricture, abscess, biloma, and pneumobilia (Fig 12) (28,30,31). At cholangiography, the appearance of the intrahepatic bile ducts is specific and includes acute tapering, straightening, rigidity, decreased arborization, and increased branching angle (Fig 12) (28,30). Characteristically, dilatation of the bile duct is not correlated with the location of lithiasis. It most likely is caused by repeated inflammation and resultant ductal destruction and loss of elasticity (28).
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Figure 12a. Cholangiocarcinoma in a 57-year-old woman with recurrent pyogenic cholangitis. (a) Portal-phase CT scan obtained at the hepatic hilar level shows dilatation of both intrahepatic bile ducts and thickened bile duct wall (straight arrows). The right hepatic lobe is atrophic. Hyperattenuating materials (arrowheads) within the dilated right intrahepatic bile ducts and ringlike calcific material (curved arrow) in the left intrahepatic bile duct were confirmed to be intrahepatic stones at surgery. (b) Portal-phase CT scan obtained at the proximal level of the common bile duct shows thickening of the bile duct wall (arrows). (c) Cholangiogram shows severe strictures (straight arrows) involving the hepatic hilum and proximal part of the common bile duct and slitlike filling of contrast material into the right hepatic duct (arrowheads). A multifaceted filling defect in the left hepatic bile duct indicates an intrahepatic stone (curved arrow). Severe dilatation of the common bile duct without an obstructing lesion in the distal part of the duct and decreased arborization of the dilated left intrahepatic bile ducts are characteristic findings of recurrent pyogenic cholangitis. (d) Photograph of the resected specimen shows thickening of the bile duct walls (arrows) and dilatation of the adjacent intrahepatic ducts (arrowheads). The thickened bile duct walls were confirmed to be infiltrative cholangiocarcinoma at histologic examination.
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Figure 12b. Cholangiocarcinoma in a 57-year-old woman with recurrent pyogenic cholangitis. (a) Portal-phase CT scan obtained at the hepatic hilar level shows dilatation of both intrahepatic bile ducts and thickened bile duct wall (straight arrows). The right hepatic lobe is atrophic. Hyperattenuating materials (arrowheads) within the dilated right intrahepatic bile ducts and ringlike calcific material (curved arrow) in the left intrahepatic bile duct were confirmed to be intrahepatic stones at surgery. (b) Portal-phase CT scan obtained at the proximal level of the common bile duct shows thickening of the bile duct wall (arrows). (c) Cholangiogram shows severe strictures (straight arrows) involving the hepatic hilum and proximal part of the common bile duct and slitlike filling of contrast material into the right hepatic duct (arrowheads). A multifaceted filling defect in the left hepatic bile duct indicates an intrahepatic stone (curved arrow). Severe dilatation of the common bile duct without an obstructing lesion in the distal part of the duct and decreased arborization of the dilated left intrahepatic bile ducts are characteristic findings of recurrent pyogenic cholangitis. (d) Photograph of the resected specimen shows thickening of the bile duct walls (arrows) and dilatation of the adjacent intrahepatic ducts (arrowheads). The thickened bile duct walls were confirmed to be infiltrative cholangiocarcinoma at histologic examination.
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Figure 12c. Cholangiocarcinoma in a 57-year-old woman with recurrent pyogenic cholangitis. (a) Portal-phase CT scan obtained at the hepatic hilar level shows dilatation of both intrahepatic bile ducts and thickened bile duct wall (straight arrows). The right hepatic lobe is atrophic. Hyperattenuating materials (arrowheads) within the dilated right intrahepatic bile ducts and ringlike calcific material (curved arrow) in the left intrahepatic bile duct were confirmed to be intrahepatic stones at surgery. (b) Portal-phase CT scan obtained at the proximal level of the common bile duct shows thickening of the bile duct wall (arrows). (c) Cholangiogram shows severe strictures (straight arrows) involving the hepatic hilum and proximal part of the common bile duct and slitlike filling of contrast material into the right hepatic duct (arrowheads). A multifaceted filling defect in the left hepatic bile duct indicates an intrahepatic stone (curved arrow). Severe dilatation of the common bile duct without an obstructing lesion in the distal part of the duct and decreased arborization of the dilated left intrahepatic bile ducts are characteristic findings of recurrent pyogenic cholangitis. (d) Photograph of the resected specimen shows thickening of the bile duct walls (arrows) and dilatation of the adjacent intrahepatic ducts (arrowheads). The thickened bile duct walls were confirmed to be infiltrative cholangiocarcinoma at histologic examination.
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Figure 12d. Cholangiocarcinoma in a 57-year-old woman with recurrent pyogenic cholangitis. (a) Portal-phase CT scan obtained at the hepatic hilar level shows dilatation of both intrahepatic bile ducts and thickened bile duct wall (straight arrows). The right hepatic lobe is atrophic. Hyperattenuating materials (arrowheads) within the dilated right intrahepatic bile ducts and ringlike calcific material (curved arrow) in the left intrahepatic bile duct were confirmed to be intrahepatic stones at surgery. (b) Portal-phase CT scan obtained at the proximal level of the common bile duct shows thickening of the bile duct wall (arrows). (c) Cholangiogram shows severe strictures (straight arrows) involving the hepatic hilum and proximal part of the common bile duct and slitlike filling of contrast material into the right hepatic duct (arrowheads). A multifaceted filling defect in the left hepatic bile duct indicates an intrahepatic stone (curved arrow). Severe dilatation of the common bile duct without an obstructing lesion in the distal part of the duct and decreased arborization of the dilated left intrahepatic bile ducts are characteristic findings of recurrent pyogenic cholangitis. (d) Photograph of the resected specimen shows thickening of the bile duct walls (arrows) and dilatation of the adjacent intrahepatic ducts (arrowheads). The thickened bile duct walls were confirmed to be infiltrative cholangiocarcinoma at histologic examination.
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The overall prevalence of recurrent pyogenic cholangitis associated with cholangiocarcinoma is 5%–6% (28), but to our knowledge, no reports of cholangiocarcinoma complicating recurrent pyogenic cholangitis have yet been published in the radiology literature.
Choledochal Cyst.—
Gallbladder carcinoma and extrahepatic cholangiocarcinoma are frequently associated with choledochal cyst, especially type I cysts of the Todani classification (33). Most cholangiocarcinomas that arise in patients with choledochal cysts are papillary adenocarcinomas (9). At imaging, they are depicted as either a polypoid mass or an irregularly thickened wall (Fig 13) (33).
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Figure 13a. Cholangiocarcinoma in a 37-year-old man with a choledochal cyst. (a, b) Portal-phase CT scan (a) and transverse sonogram (b) show a large, fungating mass (arrows) in a choledochal cyst. (c) Cholangiogram shows a large, fungating filling defect (arrows) in the distal portion of the choledochal cyst.
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Figure 13b. Cholangiocarcinoma in a 37-year-old man with a choledochal cyst. (a, b) Portal-phase CT scan (a) and transverse sonogram (b) show a large, fungating mass (arrows) in a choledochal cyst. (c) Cholangiogram shows a large, fungating filling defect (arrows) in the distal portion of the choledochal cyst.
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Figure 13c. Cholangiocarcinoma in a 37-year-old man with a choledochal cyst. (a, b) Portal-phase CT scan (a) and transverse sonogram (b) show a large, fungating mass (arrows) in a choledochal cyst. (c) Cholangiogram shows a large, fungating filling defect (arrows) in the distal portion of the choledochal cyst.
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Benign Biliary Tumors.—
On rare occasions, cholangiocarcinoma can develop from biliary papilloma and adenoma. Thus, these benign tumors are now recognized as conditions with a low-grade potential for malignancy (34).
Benign biliary tumors are depicted as solitary or, occasionally, multiple lesions that appear moderately echogenic and nonshadowing at US, hypoattenuating compared with the liver parenchyma at CT, and as filling defects or obstruction at cholangiography (Fig 14) (12,35). These US and CT findings are different from those of lithiasis, and therefore the differentiation between them is usually not difficult. However, there is no criterion to determine whether malignant foci have developed within a benign biliary tumor.
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Figure 14a. Cholangiocarcinoma in a 45-year-old man with villous adenoma. (a, b) Portal-phase CT scan (a) and oblique sonogram (b) show an intraluminal, polypoid mass (arrows) within the dilated proximal portion of the common bile duct. (c) Cholangiogram shows a polypoid filling defect with a frondlike surface (arrows) eccentrically located in the proximal part of the common bile duct.
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Figure 14b. Cholangiocarcinoma in a 45-year-old man with villous adenoma. (a, b) Portal-phase CT scan (a) and oblique sonogram (b) show an intraluminal, polypoid mass (arrows) within the dilated proximal portion of the common bile duct. (c) Cholangiogram shows a polypoid filling defect with a frondlike surface (arrows) eccentrically located in the proximal part of the common bile duct.
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Figure 14c. Cholangiocarcinoma in a 45-year-old man with villous adenoma. (a, b) Portal-phase CT scan (a) and oblique sonogram (b) show an intraluminal, polypoid mass (arrows) within the dilated proximal portion of the common bile duct. (c) Cholangiogram shows a polypoid filling defect with a frondlike surface (arrows) eccentrically located in the proximal part of the common bile duct.
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Cholangiocarcinoma Manifesting as Lobar or Segmental Atrophy
In rare cases, intrahepatic cholangiocarcinoma causes lobar or segmental atrophy when it invades and obstructs the corresponding portal vein. At imaging, such atrophy appears without a distinguishable mass lesion (Fig 15). When hilar cholangiocarcinoma is manifest as lobar atrophy, it is more likely to originate from the right or left duct rather than the hepatic hilum. Unilateral obstruction of the portal vein and bile duct can delay development of clinical symptoms (eg, jaundice) and thus produce the time lag needed for atrophic change in the diseased lobe (36).
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Figure 15a. Cholangiocarcinoma manifesting as segmental atrophy in a 65-year-old man. Arterial- (a) and equilibrium-phase (b) CT scans show crowding of the dilated intrahepatic ducts (arrows) within the atrophic left lateral segment. Tumor tissue in the atrophic segment is not clearly shown.
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Figure 15b. Cholangiocarcinoma manifesting as segmental atrophy in a 65-year-old man. Arterial- (a) and equilibrium-phase (b) CT scans show crowding of the dilated intrahepatic ducts (arrows) within the atrophic left lateral segment. Tumor tissue in the atrophic segment is not clearly shown.
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Differential Diagnoses
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Metastases
Metastatic adenocarcinoma in the liver is histologically the same as cholangiocarcinoma. Therefore, the radiologic appearance of metastatic adenocarcinoma is one of the great mimics of exophytic peripheral cholangiocarcinoma (Fig 16). Some ancillary findings, which indicate the presence of such bile duct diseases as clonorchiasis, recurrent pyogenic cholangitis, and primary sclerosing cholangitis, are helpful in differentiating cholangiocarcinoma from metastasis. Some thick-walled, bulky metastatic tumors that contain a large necrotic area in the liver (eg, metastatic leiomyosarcoma) occasionally mimic exophytic peripheral cholangiocarcinoma (Fig 17).
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Figure 16a. Metastasis in a 65-year-old patient with colonic adenocarcinoma. Arterial- (a) and equilibrium-phase (b) CT scans show a large, hypoattenuating mass (arrows) in the anterior and medial segments of both hepatic lobes. A concentric filling pattern of contrast material and morphologic features in this tumor are essentially the same as those of exophytic peripheral cholangiocarcinoma.
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Figure 16b. Metastasis in a 65-year-old patient with colonic adenocarcinoma. Arterial- (a) and equilibrium-phase (b) CT scans show a large, hypoattenuating mass (arrows) in the anterior and medial segments of both hepatic lobes. A concentric filling pattern of contrast material and morphologic features in this tumor are essentially the same as those of exophytic peripheral cholangiocarcinoma.
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Abstract
LEARNING OBJECTIVES FOR TEST...
