A 74-year-old man was admitted to our department suffering from liver injury sustained during treatment for advanced prostate carcinoma. He had been diagnosed as having asymptomatic primary biliary cholangitis 6 years earlier. Three months before admission, he began anti-androgen treatment with abiraterone acetate. Because of mildly elevated serum transaminases, abiraterone acetate was changed to bicalutamide. Although liver injury improved shortly after changing medications, severe liver injury occurred acutely 6 weeks from beginning bicalutamide, which worsened until after bicalutamide was discontinued for 11 days. Pathological findings indicated that pre-existing asymptomatic primary biliary cholangitis may worsen druginduced liver injury. This is the first report indicating the potential risk for drug-induced liver injury in the patients with asymptomatic primary biliary cholangitis despite their normalized results of serum laboratory examination.
