Cholangiocarcinoma has a poor prognosis, and resection is the only curative treatment. Pembrolizumab, a programmed death receptor 1 inhibitor, has proven effective against unresectable or metastatic solid tumors with high microsatellite instability (MSI-H) or a high tumor mutation burden (TMB-H). In the present case, pembrolizumab treatment was initiated after standard chemotherapy for MSI-H and TMB-H unresectable intrahepatic cholangiocarcinoma. Intrahepatic tumor necrosis perforated the abdominal cavity. Emergency surgery was performed, but the patient died 36 days after admission. A pathological autopsy revealed that the intrahepatic tumor had almost completely disappeared.
Keywords: microsatellite instability-high; pembrolizumab; tumor mutation burden-high; unresectable cholangiocarcinoma.