Clonorchiasis and cholangiocarcinoma: etiologic relationship and imaging diagnosis

Abstract

Despite a gradual decrease in prevalence, clonorchiasis is still prevalent in East Asia. A large and compelling body of evidence links clonorchiasis and cholangiocarcinoma, although the mechanisms involved are not completely understood. Clonorchiasis induces biliary epithelial hyperplasia and metaplasia, and this could facilitate at least one stage of the carcinogenesis, which is promoting effect. In areas of endemic infection, more clonorchiasis cases are now diagnosed incidentally during radiological examinations such as cholangiography, ultrasonography, and computed tomography. Radiological findings are regarded as pathognomonic for clonorchiasis since they reflect the unique pathological changes of this disorder. These radiological examinations currently play important roles in the diagnosis, staging, and decision-making process involved in the treatment of cholangiocarcinoma. The morphological features and radiological findings of clonorchiasis-associated cholangiocarcinoma are essentially combinations of the findings for the two diseases. The morphological features of clonorchiasis- associated cholangiocarcinoma, observed in radiological examinations, do not differ from those of the usual cholangiocarcinoma. In patients diagnosed with or suspected to have clonorchiasis, radiological findings should be carefully scrutinized for occult cholangiocarcinoma.

FIG. 1.

Histopathological findings of clonorchiasis (hematoxylin and eosin stain). Note the flukes (arrows) within the dilated bile ducts, biliary epithelial hyperplasia (arrowheads), and periductal fibrosis.

FIG. 2.

Posteroanterior endoscopic retrograde cholangiography in a 54-year-old man with clonorchiasis. Note the diffuse and uniform dilatation of the peripheral intrahepatic bile ducts with minimal dilatation of the extrahepatic bile duct and elliptical filling defects within the peripheral intrahepatic ducts, which correspond to the flukes (arrows).

FIG. 3.

Hepatic ultrasonography (right intercostal oblique plane) in a 60-year-old woman (a) and a 41-year-old man (b) with clonorchiasis. Note the diffuse, uniform dilatation of the intrahepatic bile ducts and the increased echogenicity of the ductal wall (arrowheads). Flukes or aggregates of eggs are shown as nonshadowing echogenic foci within the bile ducts (arrowheads in panel b).

FIG. 4.

Transverse hepatic computed tomography in a 45-year-old woman (a) and a 57-year-old man (b) with clonorchiasis. Note the mild, uniform dilatation of the intrahepatic bile ducts (arrowheads).

FIG. 5.

Intrahepatic peripheral cholangiocarcinoma in a 56-year-old woman. Transverse hepatic computed tomography shows a low-attenuation mass (T) in the right lobe of the liver. Note the dilated intrahepatic ducts peripheral to the tumor (arrowheads).

FIG. 6.

Hilar cholangiocarcinoma in a 58-year-old man. Transverse hepatic computed tomography (a) and right anterior oblique cholangiography (b) using a percutaneous transhepatic biliary drainage tube (curved arrow) show narrowing of the right (open arrows) and left (solid arrows) main ducts and abnormal enhancement of the ductal wall, which correspond to the tumor. Peripheral intrahepatic ducts are dilated (arrowheads).

FIG. 7.

Intraductal polypoid cholangiocarcinoma in the common bile duct of a 50-year-old woman. Posteroanterior percutaneous transhepatic cholangiography (a) and transverse hepatic computed tomography (b) show an intraductal tumor (T) within the proximal common bile duct. Arrowheads in panel a indicate the dilated intrahepatic ducts; the arrowhead in panel b indicates a percutaneous transhepatic biliary drainage tube.

FIG. 8.

Intrahepatic peripheral cholangiocarcinoma associated with clonorchiasis in a 63-year-old man. Transverse hepatic computed tomography shows a low-attenuation mass (T) at the right lobe of the liver. the severe ductal dilation peripheral to the tumor (open arrowheads in panel a [more cranial section]) is due to obstruction by the tumor. The diffuse, mild intrahepatic ductal dilatation (arrowheads in panel b [more caudal section]) is secondary to clonorchiasis.

FIG. 9.

Ampulla of Vater cancer associated with clonorchiasis in a 66-year-old man. (a) Transverse hepatic computed tomography shows diffuse severe dilatation of the entire biliary tree (arrowheads). (b) Duodenoscopy shows a luminal protruding tumor (T).

FIG. 9.

Ampulla of Vater cancer associated with clonorchiasis in a 66-year-old man. (a) Transverse hepatic computed tomography shows diffuse severe dilatation of the entire biliary tree (arrowheads). (b) Duodenoscopy shows a luminal protruding tumor (T).