Ectopic Hepatocellular Carcinoma in the Gallbladder Wall With Choledocholithiasis: A Case Report.

An ectopic hepatocellular carcinoma (HCC) that originates from the ectopic liver is defined as a hepatic organ or tissue not conventionally linked to surrounding tissues. Ectopic HCC has a rare clinical incidence, and diagnosing it before surgery is challenging. Its characteristics and biological behavior have not been fully elucidated. This report presents a unique case of ectopic HCC in the gallbladder, discontinuous with the liver. A 74-year-old man was referred to our hospital after primarily complaining of fever and right hypochondrium pain. Plain computed tomography revealed a significantly thickened gallbladder wall containing fluid collection and incarceration of gallstone in the common bile duct. He was diagnosed with acute cholecystitis and obstructive cholangitis due to choledocholithiasis. After percutaneous transhepatic gallbladder drainage and endoscopic lithotomy for choledocholithiasis, a cholecystectomy was performed. Macroscopically, the resected gallbladder had a yellowish tumor (1 cm) within the significantly thickened gallbladder wall. Histopathological examination identified moderately differentiated HCC on the ectopic liver, discontinuous with the liver. Immunohistologically, the tumor was finally diagnosed as ectopic HCC with alpha-fetoprotein positive expression.