British Journal of Radiology 75 (2002),497-501 © 2002 The British Institute of Radiology
CT imaging of intrabiliary growth of colorectal liver metastases: a comparison of pathological findings of resected specimens
K Okano, MD
1
J Yamamoto, MD
2
T Okabayashi, MD
1
Y Sugawara, MD
1
K Shimada, MD
1
T Kosuge, MD
1
S Yamasaki, MD
1
H Furukawa, MD
3 and
Y Muramatsu, MD
3
Departments of 1 Surgery and 2 Diagnostic Radiology, National Cancer Center Hospital, 5-1-1, Tsukiji, Chuo-ku, Tokyo 104-0045 and 3 Department of Gastrointestinal Surgery, Cancer Institute Hospital, 1-37-1, Kami-ikebukuro, Toshima-ku, Tokyo 170-8455, Japan
Correspondence: Junji Yamamoto, MD
 |
Abstract
|
|---|
The objective of this study was to assess the usefulness of CT in the pre-operative evaluation of macroscopic intrabiliary tumour growth of colorectal liver metastases. 25 metastatic nodules of 18 patients who underwent an initial hepatectomy for colorectal liver metastasis were retrospectively evaluated. The CT appearance and pathological findings of the resected specimens were correlated. A number of unusual peritumoral features associated with intrabiliary tumour growth were detected by pre-operative CT. These were classified into three patterns: (1) thickened portal tract; (2) intrahepatic bile duct dilatation; and (3) a wedge-shaped area with enhancement. In 8 (32%) of the 25 nodules the portal tract was depicted as thicker than usual and these features were found proximal to the tumour in three instances, distal to the tumour in four instances, and both proximal and distal in one instance. All of the three intrabiliary tumours larger than 30 mm resulted in thickening of the portal tract. Intrahepatic bile duct dilatation was detected in association with 10 (40%) of 25 nodules. Bile duct dilatation was observed in more than one segment when intrabiliary tumour reached the hepatic hilus from the tumour. The presence of bile duct dilatation was not related to either the size of the tumour or the extent of intrabiliary tumour growth. An abnormally high density wedge-shaped area on contrast enhanced CT was another feature indicating intrabiliary tumour growth and was seen in association with four nodules. Such areas were seen in the liver parenchyma distal to the tumour on three occasions, or encompassing the tumour on one accasion. This wedge-shaped area appeared as a well demarcated dark red–brown region in the cut surface of the resected specimen. CT was useful for detecting the presence of intrabiliary tumour growth with these three patterns of radiological findings in patients with liver metastases from colorectal cancer
|
Introduction
|
|---|
Imaging techniques have recently advanced to enable accurate evaluation of the status of metastatic deposits in the liver [1]. In a previous study, we reported that metastatic tumours from colorectal cancer had a great affinity for the intrahepatic portal tract, and showed invasion of the portal vein and bile duct [2]. Among these pathological findings, macroscopic intrabiliary invasion was a paradoxical favourable prognostic factor indicating indolent tumour characteristics and favourable post-resection outcome [3, 4]. Thus, pre-operative information regarding such a factor is crucial for determining which patients would benefit from surgery. A few studies have emphasized the value of pre-operative identification of tumour spread along the portal triad of colorectal metastases [5]. The purpose of our study was to assess the usefulness of CT in the pre-operative evaluation of macroscopic intrabiliary growth of hepatic metastatic disease from colorectal cancer.
|
Materials and methods
|
|---|
149 patients underwent an initial hepatectomy for colorectal liver metastasis at the National Cancer Center Hospital, Tokyo, Japan, between 1992 and 1996. The CT and pathological findings of their resected specimens were analysed.
CT was obtained with a 900 s or X-Vigor scanner (Toshiba Medical System, Tokyo, Japan) with a 7–10 mm slice thickness, within 30 days prior to hepatectomy. Enhanced CT was performed with 100–120 ml of 61% iopamidol (Iopamiron; Schering, Berlin, Germany) injected at a rate of 2–3 ml s-1 into the antecubital vein in all patients. Scanning began 35–40 s after the start of contrast medium injection.
Immediately after resection the surgical specimens were sliced 5 mm thick and macroscopic examination was performed according to the routine service of the pathology department. The specimens were then fixed in 10% formaldehyde solution, embedded in paraffin and stained with hematoxylin and eosin. Macroscopic information included number, size, gross extension pattern of each tumour and distance from the tumour edge to the tip of the intrabiliary growing tumour. Invasion to the intrahepatic bile duct was also confirmed by microscopic examination.
A total of 464 nodules were resected from 149 patients. 25 tumours in 18 patients (male:female, 12:6; median age 65 years, age range 47–75 years) showed gross extension into the bile duct in the resected specimens. The distance from the edge of the nodule to the tip of the intrabiliary tumour ranged from 4 mm to 42 mm (median 13 mm). These nodules ranged in size from 5 mm to 90 mm, with a mean of 35 mm (long axis of the tumour).
The CT images of the 25 nodules in these 18 patients were examined and compared with macroscopic and microscopic findings of the resected specimens.
|
Results
|
|---|
On pre-operative CT images, unusual peritumoral findings associated with intrabiliary tumour growth were seen around the tumour in 16 (64%) of 25 nodules. Such features around the tumour on CT were classified into three patterns: (1) thickened portal tract; (2) intrahepatic bile duct dilatation; and (3) a wedge-shaped area with enhancement. The relationships between the length of intrabiliary tumour growth and these three types of CT findings are summarized in Table 1
.
View this table:
[in this window]
[in a new window]
|
Table 1. CT findings of macroscopic intrabiliary growth of colorectal liver metastases in relation to length of the intrabiliary tumour
|
|
Thickened portal tract
The portal tract was depicted thicker than usual in 8 (32%) of 25 nodules on both non-enhanced and enhanced CT (Figure 1). These radiographic features were found proximal to the tumour in three nodules, distal to the tumour in four nodules, and both proximal and distal in one nodule. In the resected specimens, the portal triad was also observed to be widened due to the tumour cast in the bile duct. All of the three intrabiliary tumours larger than 30 mm showed thickening of the portal tract. Prominent tumour growth into the bile duct from the peripheral tumour to the hepatic hilus was observed in two nodules (42 mm and 31 mm).
View larger version (88K):
[in this window]
[in a new window]
|
Figure 1. Liver metastases from sigmoid colon cancer in a 60-year-old man. (a) Unenhanced CT shows a peripherally located low density mass (T) and a low density area along the portal tract (arrowheads). (b)Enhanced CT shows enhancement of the peripheral tumour (T) and a thickened portal tract connected with the tumour as a high density area (arrowheads). (c) Photograph of the resected specimen shows a metastatic tumour located in segment V (Couinaud's nomenclature) and tumour growth in the bile duct (arrows) extending 31 mm from the tumour toward the right hepatic duct.
|
|
Intrahepatic bile duct dilatation
Intrahepatic bile duct dilatation was detected in 10 (40%) of 25 nodules. Bile duct dilatation that extended over more than one segment was seen in association with two nodules (Figures 2a,b). In these two cases, intrabiliary tumour grew up to the hepatic hilus from the tumour (Figure 2c). In the other nodules, intrahepatic bile duct dilatation was observed in the confined area distal to the tumour (6 of 8 nodules). The median tumour size was37 mm (range 10–90 mm) and 42 mm (range 21–75 mm) in the lesions with and without bile duct dilatation, respectively. The presence of intrahepatic bile duct dilatation was not related to either the size of the tumour or the length of intrabiliary tumour growth (Table 1
).
View larger version (92K):
[in this window]
[in a new window]
|
Figure 2. Liver metastasis from descending colon cancer in a 72-year-old woman. (a) Enhanced CT shows a metastatic lesion as a low density mass and intrahepatic bile duct dilatation mainly in the posterior segment of the right hepatic lobe. (b) Contiguous CT section also shows intrahepatic bile duct dilatation and intrabiliary tumour growth (arrowheads) shown as a low density area along the route of the right hepatic duct. (c) Photograph of the resected specimen shows that the intrabiliary tumour (arrowheads) extended 14 mm from the tumour located in segment VI/VII into the right hepatic duct (stretched with threads).
|
|
Wedge-shaped area with enhancement
An abnormally high density wedge-shaped area appeared on contrast enhanced CT in association with four nodules. Such areas were seen only on post-contrast enhanced images. All these four areas were seen at the periphery of the liver (Figure 3). In three nodules such areas were seen in the liver parenchyma distal to the tumour. In one nodule located at the liver periphery with intrabiliary tumour invading into the proximal bile duct, the wedge-shaped area encompassed the tumour. In one nodule this area was recognized in combination with a thickened portal tract.
View larger version (70K):
[in this window]
[in a new window]
|
Figure 3. Liver metastases from sigmoid colon cancer in a 61-year-old man. (a) Enhanced CT shows a peripheral wedge-shaped high attenuation area in segment VIII. (b) Photograph of the resected specimen shows a metastatic tumour with intrabiliary tumour (arrowheads) that extended 15 mm proximally and distally.
|
|
|
Discussion
|
|---|
Macroscopic intrabiliary invasion by metastatic liver tumour is observed in more than 10% of patients with resectable metastatic disease from colorectal cancer [2, 3, 5]. Pre-operative detection of such a growth pattern is important in clinical practice for treating patients with these metastatic tumours, since such findings indicate a paradoxically indolent feature of the tumour and indicate a good prognosis after surgical removal. Since the gross intra-bile duct extension protrudes like a bud from the round contour of the tumour, liver transection along the tumour may leave malignant tissue at the stump of the invaded bile duct. Since a positive resection margin has been reported to be one of the most important determinants of poor survival, pre-operative information regarding tumour invasion into the portal triad is essential for the surgeon [3, 6].
Many studies have reported imaging techniques for evaluating the exact number and location of metastases. However, pre-operative CT imaging of macroscopic intrabiliary growth of colorectal metastases has not been reported. Several studies describing hepatocellular carcinoma with gross intrabiliary tumour indicated that the tumour is associated with frequent invasion to the portal vein and a poor prognosis [7–9]. They indicated that the diffuse intrahepatic bile duct dilatation and obstructive jaundice associated with hepatocellular carcinoma suggested the presence of intrabiliary tumour. In our series of colorectal metastases, CT findings associated with macroscopic intrabiliary growth could be classified into three patterns. All of the nodules with intrabiliary tumour larger than 20 mm showed some of these three findings on pre-operative CT.
A thickened portal tract around the tumour corresponded to intrabiliary tumour itself, while intrahepatic biliary dilatation and a wedge-shaped area are findings accompanying intrabiliary tumour growth. Detection of a thickened portal tract by CT depended on the length of the intrabiliary tumour, while depiction of the other findings was not related to extension of the intrabiliary tumour. Intrabiliary tumours larger than 30 mm were generally depicted as a thickened portal tract. On the other hand, those ranging from 20 mm to 29 mm were accompanied by a simple dilated bile duct (Table 1). In our series, extensive bile duct dilatation was a relatively rare finding (8%). One patient showed obstructive jaundice with extensive intrahepatic bile duct dilatation owing to involvement of the bile duct of the hepatic hilus and received pre-operative percutaneous transhepatic biliary drainage. Intrahepatic bile duct dilatation was observed with eight nodules without a finding of a thickened portal tract and was useful for recognizing less extensive intrabiliary tumour growth.
The wedge-shaped area with enhancement was assumed to be owing to reduced portal flow and a compensatory increase in arterial blood flow caused by tumour compression or arterioportal shunt in the involved portal venous branch [10]. In hepatocellular carcinoma, the appearance of arterioportal shunt suggests the presence of portal vein thrombosis [11]. In our series, there was no evidence of macroscopic tumour thrombus in the portal venous branches among four nodules that showed a wedge-shaped area, whereas only one had microscopic portal vein invasion. Macroscopically, corresponding liver parenchyma was observed as a dark red wedge-shaped area and microscopic examination revealed liver cell atrophy, sinusoidal dilatation and inflammation of the perivascular fibrous tissue of this area. Muramatsu et al [4] reported that wedge-shaped increased signal intensity on T1 weighted MRI associated with liver tumours indicated intrabiliary tumour extension. They observed lipofuscin deposits, which consisted of phospholipids and fatty acids, in atrophic hepatocytes around the enlarged intrahepatic bile duct with intrabiliary tumour.
In conclusion, CT provides useful information regarding macroscopic bile duct invasion of colorectal liver metastases, although in cases with invasion of less than 20 mm, indicative features may not be seen. A thickened portal tract, intrahepatic bile duct dilatation and an enhanced wedge-shaped area on CT suggest the presence of macroscopic intrabiliary invasion of colorectal metastatic liver tumours. The pre-operative diagnosis of intrabiliary tumour invasion would be facilitated by a greater awareness of this exceptional growth feature.
|
Footnotes
|
|---|
This study was supported by a grant-in-aid for Cancer Research from the Ministry of Health and Welfare of Japan. 
Received for publication January 30, 2001.
Accepted for publication March 15, 2002.
|
References
|
|---|
- Soyer P, Levesque M, Elias D, Zeitoun G, Roche A. Detection of liver metastases from colorectal cancer: comparison of intraoperative US and CT during arterial portography. Radiology 1992;183:541–4.[Abstract/Free Full Text]
- Yamamoto J, Sugihara K, Kosuge T, et al. Pathologic support for limited hepatectomy in the treatment of liver metastasis from colorectal cancer. Ann Surg 1995;221:74–8.[Medline]
- Yamamoto J, Shimada K, Kosuge T, Yamasaki S, Sakamoto M, Fukuda H. Factors influencing survival of patients undergoing hepatectomy for colorectal metastases. Br J Surg 1999;86:332–7.[Medline]
- Okano K, Yamamoto J, Moriya Y, et al. Macroscopic intrabiliary growth of liver metastases from colorectal cancer. Surgery 1999;126:829–34.[Medline]
- Muramatsu Y, Takayasu K, Furukawa Y, et al. Hepatic tumor invasion of bile ducts: wedge-shaped sign on MR images. Radiology 1997;205:81–5.[Abstract/Free Full Text]
- Doci R, Gennari L, Bignami P, Montalto F, Bozzetti F. One hundred patients with hepatic metastases from colorectal cancer treated by resection: analysis of prognostic determinants. Br J Surg 1991;78:797–801.[Medline]
- Kojiro M, Kawabata K, Kawano Y, Shirai F, Takemoto N, Nakashima T. Hepatocellular carcinoma presenting as intrabile duct tumor growth. Cancer 1982;49:2144–7.[Medline]
- Kubota Y, Seki T, Kunieda K, et al. Biliary endoprosthesis in bile duct obstruction secondary to hepatocellular carcinoma. Abdom Imaging 1993;18:70–5.[Medline]
- Soyer P, Laissy JP, Bluemke DA, Sibert A, Menu Y. Bile duct involvement in hepatocellular carcinoma: MR demonstration. Abdom Imaging 1995;20:118–21.[Medline]
- Imoto K, Sugiki K, Yamasaki H, et al. CT of hepatoma: effects of portal vein obstruction. AJR 1981;136:349–53.[Abstract/Free Full Text]
- Itai Y, Furui S, Ohotomo K, et al. Dynamic CT features of arterioportal shunts in hepatocellular carcinoma. AJR 1986;146:723–7.[Abstract/Free Full Text]
This article has been cited by other articles:
|
|
|
|
 
Y. J. Lee, S. H. Kim, J. Y. Lee, M. A Kim, J. M. Lee, J. K. Han, and B. I. Choi
Differential CT Features of Intraductal Biliary Metastasis and Double Primary Intraductal Polypoid Cholangiocarcinoma in Patients With a History of Extrabiliary Malignancy
Am. J. Roentgenol.,
October 1, 2009;
193(4):
1061 - 1069.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
K. S. Jhaveri, J. Halankar, D. Aguirre, M. Haider, G. Lockwood, M. Guindi, and S. Fischer
Intrahepatic Bile Duct Dilatation Due to Liver Metastases From Colorectal Carcinoma
Am. J. Roentgenol.,
September 1, 2009;
193(3):
752 - 756.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
C. O. Menias, V. R. Surabhi, S. R. Prasad, H. L. Wang, V. R. Narra, and K. N. Chintapalli
Mimics of Cholangiocarcinoma: Spectrum of Disease1
RadioGraphics,
July 1, 2008;
28(4):
1115 - 1129.
[Abstract]
[Full Text]
[PDF]
|
|
|
Top
Abstract
Introduction
