Invasive growth patterns of hepatic hilar ductal carcinoma. A histologic analysis of 18 surgical cases.

Background. Postoperative recurrence of hepatic hilar ductal carcinoma usually occurs in a localized region around the surgical margin, such as the bile duct. This study was aimed at assessing the invasive patterns of the hepatic hilar ductal carcinoma by histologically examining surgical specimens obtained by extended liver resection, especially the involvement of intrahepatic duct. Methods. Eighteen resected specimens of hepatic hilar d.uctal carcinoma were histologically investigated. Multiple sections vertical to the extrahepatic and intrahepatic bile duct were made at a 5-mm interval. The extension of carcinoma was evaluated on each of three layers (mucosal, extramucosal-intramural, and extramural), and routes of the invasion were examined