Pembrolizumab-induced sclerosing cholangitis in a lung adenocarcinoma patient with a remarkable response to chemotherapy: a case report.

A 68-year-old man with advanced lung adenocarcinoma was admitted to our department because of high levels of alkaline phosphatase (ALP) after 4 courses of chemotherapy, including pembrolizumab. An imaging study showed findings of sclerosing cholangitis in the intrahepatic bile duct. Liver histology revealed infiltration of CD8-positive T cells into the portal tract. Corticosteroid and ursodeoxycholic acid were administered, and the ALP levels and findings of sclerosing cholangitis gradually improved. Furthermore, his lung carcinoma was remarkably decreased by chemotherapy, and he did not show progression of cancer without treatment. Our case suggests that early treatment before developing jaundice may be effective for sclerosing cholangitis in the intrahepatic bile duct due to immune checkpoint inhibitors.