Figure 5 Gross and microscopic features of the tumor. (Schema) Tumor extension in the biliary system showing a negative distal margin (black line) and a positive hepatic margin (red line). (Gross appearance) The main tumor was located in the hepatic hilar area (yellow circle) and was attached to the right hepatic artery (yellow arrowheads). The surgical sonde was passed through the common biliary duct into the right hepatic duct. (A) Hematoxylin and eosin staining of the right hepatic duct margin showing carcinoma cells crawling along the bile duct wall. (B) Hematoxylin and eosin staining of the main tumor showing a moderate chemotherapeutic effect with 50% residual tumor cells. (C) Immunostaining of the main tumor showing positive somatostatin type-2 receptor, negative Rb1, and positive p53 expression.