208 Part V – Biliary Tree Abnormalities
97Gallbladder Carcinoma II – Hepatoid Type of Adenocarcinoma
Hepatoid adenocarcinoma (HAC) is a rare variant of extrahepatic adenocarcinoma, consisting of foci of both adenomatous and hepatocellular differentiations which behave like hepatocellular carcinoma (HCC) in morphology and functionality. It occurs in a multitude of organs, most frequently in the stomach, but it has been reported to occur rarely in other areas as well, including the lung, kidney, female reproductive tract, pancreas, and gallbladder. Typically, an elevated level of serum alpha-fetoprotein (AFP) is detected, although normal levels have also been reported. At imaging the tumor in combination with elevated AFP may mimic HCC.
MR Imaging Findings
At T2-weighted MR imaging the tumor has a typical morphology of an intrahepatic cholangiocarcinoma (low signal centrally due to desmoplasia with a thick rim of high signal peripherally). Also the enhancement pattern is similar to intrahepatic cholangiocarcinomas. Specific contrast media such as superparamagnetic iron oxide (SPIO) may show lack of Kupffer cells (Figs. 97.1 – 97.3).
Literature
1.Ishikura H, Kishimoto T, Andachi H, et al. (1997) Gastrointestinal hepatoid adenocarcinoma: venous permeation and mimicry of hepatocellular carcinoma, a report of four cases. Histopathology 31:47 – 54
2.Terracciano LM, Glatz K, Mhawech P, et al. (2003) Hepatoid adenocarcinoma with liver metastasis mimicking hepatocellular carcinoma: an immunohistochemical and molecular study of eight cases. Am J Surg Pathol 27:1302 – 1312
3.Sakamoto K, Monobe Y, Kouno M, et al. (2004) Hepatoid adenocarcinoma of the gallbladder: case report and review of the literature. Pathol Int 54:52 – 56
4.Van den Bos IC, Hussain SM, Dwarkasing RS, et al. Hepatoid adenocarcinoma of the gallbladder: a mimicker of hepatocellular carcinoma. BJR (in press)
Differential Diagnosis
Especially with involvement of the gallbladder wall, differentiation from HCC or combined HCC and cholangiocarcinoma is challenging. At immunohistochemistry, CD10 may be positive indicating canalicular differentiation, and positive CD7 and CD19 indicate bile duct adenocarcinoma, since HCC is generally not positive for CD10, CD7 and CD19. In addition, the staining for cytoplasmic AFP may be positive. This combination with the morphology and anatomic location are suggestive for HAC.
97 Gallbladder Carcinoma II – Hepatoid Type of Adenocarcinoma 209
Fig. 97.1. Gallbladder hepatoid adenocarcinoma (HAC), drawings. BBEPI: HAC is hyperintense to the liver and arises from the gallbladder; T1 in-phase: HAC
Fig. 97.2. Gallbladder hepatoid adenocarcinoma (HAC), MRI findings. A Axial black-blood echoplanar imaging (BBEPI): HAC is hyperintense to the liver with a hypointense center due to desmoplasia that is a typical feature of cholangiocarcinomas. B Axial in-phase image (T1 in-phase): HAC is hypointense to the liver with umbilication caused by central desmoplasia (open arrow). C Axial arterial phase image (ART): HAC shows heterogeneous enhancement with some perilesional enhancement. D Axial delayed phase
is hypointense to the liver; ART: HAC shows heterogeneous enhancement; DEL: HAC shows enhancement of the more fibrotic central part of the tumor
image (DEL): HAC shows enhancement of more fibrotic areas. E Axial SSTSE image with longer TE (SSTSE): HAC is brighter in the periphery and darker in the center (*) with an umbilication (open arrow). F Axial opposedphase image (T1 opposed-phase): HAC is hypointense to the liver. G Coronal SSTSE image (SSTSE): HAC is brighter in the periphery and darker in the center (*). H Coronal delayed phase image (DEL): HAC shows enhancement of more fibrotic central areas (*)
Fig. 97.3. Gallbladder hepatoid adenocarcinoma at a different anatomic level. A Axial black-blood EPI (BBEPI): HAC is hyperintense to the liver with a small intrahepatic metastasis (arrow). B Axial BBEPI after the uptake of SPIO: the liver and spleen show signal loss, whereas the metastasis (arrows)
remains bright. C Axial arterial phase image (ART): HAC shows enhancement of mainly the growing edge of the tumor. D Drawing illustrates the tumor anatomy: tumor center (*). Metastasis (arrow)
210 Part V – Biliary Tree Abnormalities
98 Hilar Cholangiocarcinoma I – Typical
Cholangiocarcinoma (CC) represents less than 1 % of all newly diagnosed cancers in North America. Hilar CC (Klatskin tumor) is an adenocarcinoma arising from the hepatic duct or near its bifurcation. Hilar CC accounts for 10 – 25 % of all CC. This tumor is generally divided into three types: infiltrative (spread along the wall of the duct), nodular (tending to obliterate the duct), and papillary (rare intraductal variant). Overall 5-year survival rate is 1 %. Even after so-called curative resection, the 5-year survival rate is only 20 % because of the locally invasive nature of the tumor. The tumor may be associated with primary sclerosing cholangitis, Caroli’s disease, biliary lithiasis, clonorchiasis, and recurrent pyogenic cholangitis. MR imaging with MRCP is a non-invasive technique which can play an important role in the workup of these lesions. MR imaging provides an overview of the biliary anatomy and facilitates the delineation of the tumor from the surrounding liver parenchyma.
Literature
1.Lee WJ, Lim HK, Jang KM, et al. (2001) Radiologic spectrum of cholangiocarcinoma: emphasis on unusual manifestation and differential diagnoses. Radiographics 21:S97–S116
2.Klatskin G (1965) Adenocarcinoma of the hepatic duct at its bifurcation within the porta hepatis: an unusual tumor with distinctive clinical and pathological features. Am J Med 38:241 – 256
3.Bismuth H, Corlette MB (1975) Intrahepatic cholangioenteric anastomosis in carcinoma of the hilus of the liver. Surg Gynecol Obstet 140: 170 – 178
MR Imaging Findings
At MR imaging, hilar cholangiocarcinoma may only be visible indirectly by the dilated intrahepatic bile ducts that end abruptly at the hilum, causing a negative impression of the mass. At T2-weighted images, the mass may have subtle increased signal compared to the surrounding liver and on T1-weighted images. The findings may be unremarkable. After injection of gadolinium, the tumors may show ring-shaped or heterogeneous enhancement with persistent (heterogeneous) enhancement in the later phases (Figs. 98.1, 98.2). Other tumors may show little or no enhancement. The exact delineation of the tumor (Bismuth classification), which is essential for any curative surgery, may be challenging on state-of-the-art MR imaging. In our experience, such aspects are even more challenging on US and CT.
Pathology
Most cholangiocarcinomas are mainly composed of desmoplastic matrix, which contains islands of tumor cells. The tumor typically infiltrates the adjacent tissues in finger-like extensions. Often a few vessels will be present. The combination of extensive desmoplastic matrix (relatively low signal on T2), infiltrative growth pattern, and hypovascularity makes it difficult to delineate the tumor from the surroundings on imaging (Fig. 98.3).
98 Hilar Cholangiocarcinoma I – Typical 211
Fig. 98.1. Hilar cholangiocarcinoma (CC), drawings. T2 fatsat: CC is slightly hyperintense to the surrounding liver with dilated bile ducts (arrow). T1 fatsat: CC is slightly hypointense to the surrounding liver (arrow). ART: CC shows irregular ring-shaped enhancement with an enhancing wedge-
Fig. 98.2. Hilar cholangiocarcinoma (CC), MR findings. A Axial fat-suppressed TSE image (T2 fatsat): CC is slightly higher in signal intensity than the surrounding liver (arrows). B Axial fat suppressed T1-w GRE (T1fatsat): CC is slightly hypointense. C Axial arterial phase 3D gradient recalled echo (GRE) image (ART): CC shows irregular ring-shaped enhancement (arrows) with a wedge-shaped enhancement of a part of the liver due to portal compression. D Axial delayed phase image (DEL): CC shows faint heterogeneous en-
shaped area due to the portal compression. DEL: CC shows faint heterogeneous enhancement with some residual wedge-shaped enhancement of the liver
hancement of the CC with some residual wedge-shaped enhancement. E Axial SSTSE image (SSTSE) shows the bright (fluid-containing) dilated bile ducts that end abruptly, suggesting a lesion at the hilum of the liver. F A 2D 20-mm-thick-slab MRCP (MRCP) shows the dilated bile ducts with a central area of sudden caliber change. G A detailed view of MRCP shows the dilated ducts with caliber change in more detail (arrows). H A detailed view from the axial delayed phase image (DEL) indirectly suggests a mass (arrows)
Fig. 98.3. Hilar cholangiocarcinoma (CC), histology (another patient), drawings. A
Photomicrograph shows the demarcation (dashed blue line) between the CC and the liver with finger-like ingrowth of the tumor. H&E, × 40. B Photomi-
crograph shows CC composed of tumor matrix of desmoplasia with scattered glandular structures. H&E, × 100. C Photomicrograph shows epithelium of the glands (arrows). H&E, × 200. D Drawing based on the MRCP above