Extramedullary metastasis of the hilar bile duct in multiple myeloma: a case report and literature review - Liu, Fei; Li, Wei; Wu, Wanfeng; Teng, Buwei; Li, Wenlei; Li, Kai; Li, Xiangcheng (Journal of Gastrointestinal Oncology; Vol 16, No 5 (October 31, 2025): Journal of Gastrointestinal Oncology, 2025)