Vanishing bile duct syndrome following pembrolizumab infusion: case report and review of the literature.

PD-1/PD-L1 inhibitors demonstrate high efficacy in non-small-cell lung cancer and are now routinely used in clinical practice. Severe immune-related adverse events are reported in about 5% of patients, requiring hospitalization and possibly leading to death. We present a rare case of vanishing bile duct syndrome that arose a few days after the first pembrolizumab infusion. Laboratory tests and radiological imaging studies were performed to orient diagnosis and monitor the disease, while the evidence of ductal loss on the histological sample was pathognomonic for vanishing bile duct syndrome. High-dose steroid therapy and immunosuppressors were administered, resulting in scarce efficacy. Prompt recognition and management of similar conditions is crucial to avoid fatal events. Further studies are needed to investigate new drugs for steroid-refractory conditions.