Cholangiocarcinoma (CCA), the second most common primary malignant tumor of the liver after HCC, arises from intrahepatic and extrahepatic bile ducts. It accounts for 3% of gastrointestinal cancers in the United States, where there are approximately 2000 to 3000 new cases each year. However, in some regions of southeast Asia such as northeastern Thailand, Laos, and Cambodia where infestation with liver flukes is endemic, cholangiocarcinoma is much more common, occurring at rates 30 to 40 times higher than in areas of Asia without liver fluke infestation.
All risk factors for cholangiocarcinoma cause chronic inflammation and cholestasis, which presumably promote occurrence of somatic mutations or epigenetic alterations in cholangiocytes. The risk factors include infestation by liver flukes (particularly Opisthorchis and Clonorchis species), chronic inflammatory disease of the large bile ducts (such as primary sclerosing cholangitis), hepatolithiasis, and fibropolycystic liver disease. As with HCC, rates of cholangiocarcinoma also are elevated in patients with hepatitis B and C and NAFLD.
lesionsatthetimeofdiagnosis,astheycauseobstructionofthe biliarytractearlyintheircourse.Mosttumorsappearasfirm, infiltrative,whileothersarepapillaryorpolypoid.Intrahepatic
Fig.16.38A produceasinglemassivetumor.
cinomas.Mostarewelltomoderatelydifferentiated,growingas
Fig.16.38B ).Theytypicallyincitemarkeddesmoplasia.Lym metastases.
http://ebooksmedicine.net
Fig. 16.38 Cholangiocarcinoma.(A)MultifocalcholangiocarcinomainaliverfromapatientwithinfestationbytheliverflukeClonorchis sinensis (flukesnotvisible)(B)Invasivemalignantglandsinareactive,scleroticstroma.(A, Courtesy of Dr.Wilson M.S.Tsui, Caritas Medical Centre, Hong Kong.)
Theliveristhemostcommonsiteofmetastaticcancersfromprimarytumorsofthecolon,lung,andbreast.
Hepatocellular adenomas arebenigntumorsofhepatocytes.Mostcanbesubclassifiedonthebasisofmolecularchangeswithvaryingdegreesofmalignantpotential.Theyareassociatedwithuseoforalcontraceptivesandandrogens.
Thetwomaintypesofmalignanttumorsarehepatocellular carcinomas and cholangiocarcinomas;HCCsaremuchmorecommon.
HCCisacommontumorinregionsofAsiaandAfrica,anditsincidenceisincreasingintheUnitedStates.
ThemainetiologicagentsforHCCarehepatitisBandC,alcoholiccirrhosis,hemochromatosis,andexposuretoaflatoxins.IntheWesternpopulation,about90%ofHCCsdevelopincirrhoticlivers;inAsia,almost50%ofcasesdevelopinnoncirrhoticlivers.
Thechronicinflammationandcellularregenerationassociatedwithviralhepatitisarepredisposingfactorsforthedevelopmentofcarcinomas.
HCCmaybeunifocalormultifocal,tendstoinvadebloodvessels,andrecapitulatesnormalliverarchitecturetovaryingdegrees.
Cholangiocarcinomaisatumorofintrahepaticorextrahepaticbileductsthatisrelativelycommoninareaswhereliverflukes,suchasOpisthorchis andClonorchis species,areendemic.