Its diagnosis should follow 2022 WHO and 2022 ICC recommendations (6, 7), requiring immunohistochemical and molecular characterization of histological samples, including markers such as CD45, CD20, CD19, CD79a, PAX5, CD3, CD5, BCL6, CD10, BCL2, c-MYC, Ki67, and IRF4/MUM1. The gene discussed is MKI67; the disease is intrahepatic cholangiocarcinoma.