Specifically, compared with the large duct type, the small duct type is characterized by better long-term outcomes with less aggressive pathological features, such as lymphatic and/or perineural invasion, and more frequent genetic alterations, such as IDH1/2 or BAP1 mutations, and FGFR2 fusions, which are treatable with currently available and promising targeted therapies, such as Pemigatinib for ICC with FGFR2 fusion/rearrangement or Ivosidenib for ICC with IDH1 mutations. The gene discussed is BAP1; the disease is intrahepatic cholangiocarcinoma.