Residual biliary intraepithelial neoplasia without malignant transformation at resection margin for perihilar cholangiocarcinoma does not require expanded resection: a dual center retrospective study. - Xu, Zeliang; Fan, Xiaoyi; Zhang, Chengcheng; Li, Yuancheng; Jiang, Di; Hu, Feng; Pan, Bi; Huang, Yixian; Zhang, Leida; Lau, Wan Yee; Liu, Xingchao; Chen, Zhiyu (World Journal of Surgical Oncology, 2024)