Preoperative imaging studies. (A-D) Contrast-enhanced computed tomography (CT). Arrowheads indicate gallbladder tumor with a peripheral wall enhancement extending to the liver parenchyma adjacent to (A) the gallbladder and (B) the transverse colon. (C) Arrowheads indicate an enlarged lymph node with a diameter of 23 mm, which was detected in the area of the cystic duct. (D) Arrowheads indicate the right hepatic artery (RHA), which runs close to an enlarged lymph node, suggesting that extracapsular invasion extended to the RHA. (E) Endoscopic retrograde cholangiopancreatography: arrowheads indicate a stricture at the level of the junction of the cystic duct and the common hepatic duct. (F) Fluorodeoxyglucose positron emission tomography. The arrowhead and arrow indicate high fluorodeoxyglucose uptake in the gallbladder tumor and cystic duct lymph node, respectively.