[A case of hepatocellular carcinoma invading the gallbladder misdiagnosed as a primary gallbladder carcinoma].

Extrahepatic metastasis of hepatocellular carcinoma (HCC) is occasionally seen in the lung, bone, adrenal gland, and lymph nodes. It is well known that HCC sometimes invades the biliary system. Since there is no peritoneum between the gallbladder and the liver fossa, a gallbladder cancer easily invades the liver; however, HCC seldom invades the gallbladder because it rarely destroys the muscle layer or the collagen fibers of the gallbladder wall. Routes of gallbladder metastasis of HCC include direct invasion, extension to the biliary system, and invasion of the adjacent hepatic vascular system. Some cases of gallbladder metastasis of HCC without direct invasion have been reported. We report here a case of HCC that directly invaded the gallbladder, and that resembled gallbladder carcinoma invading the liver.