[A case of pembrolizumab-induced sclerosing cholangitis that was responsive to high-dose steroid therapy].

An 80-year-old woman was treated with pembrolizumab for non-small cell lung carcinoma. The hepatobiliary enzymes of the patient were elevated before the start of the ninth treatment cycle. The patient was diagnosed with pembrolizumab-induced sclerosing cholangitis based on magnetic resonance cholangiopancreatography and liver biopsy. Liver dysfunction improved with steroid therapy, and hepatobiliary enzymes increased again. The patient was treated with methylprednisolone (1000mg/day for 3 days) followed by oral prednisolone (1mg/kg/day). The patient's hepatobiliary enzymes subsequently decreased, and the oral prednisolone was tapered. Another liver biopsy, which showed a decrease in the hepatic CD8+ T cell count, was performed. Liver dysfunction did not recur although steroid therapy was discontinued after 1 year of administration.