Immunotherapy is increasingly used to treat various types of cancer; however, it can often result in immune-related adverse events (irAEs). Immune-related sclerosing cholangitis (irSC) is a rare type of hepatic irAE that has been described only in a few cases, and much remains unknown about its optimal treatment. In this report, we describe the case of a man in his 70s who was diagnosed with metastatic melanoma and treated with pembrolizumab. He experienced multiple irAEs, including irSC, which did not respond to initial prednisone treatment (2 mg/kg daily dosing). However, subsequent treatment with ursodeoxycholic acid (UDCA) resulted in complete resolution of symptoms and normalisation of laboratory and radiographic abnormalities related to irSC. Our case suggests that steroids, which are traditionally used to treat irAEs, may be ineffective for irSC and that UDCA may be a better alternative. Clinicians should be aware of this rare irAE.
