A Case of Delayed Immune Checkpoint Inhibitor Hepatitis in a Patient with Malignant Melanoma

Immune checkpoint inhibitors are an increasingly utilized class of medications in oncology. Significant adverse effects have been reported, including hepatitis which mostly occurs early after initiating treatment. We present a case of a 78-year-old male with past medical history of recurrent sinusoidal mucosal malignant melanoma on pembrolizumab for three years that presented with painless jaundice of 72-hour duration. Laboratory evaluation demonstrated alkaline phosphatase at 1780 IU/L, aspartate aminotransferase at 2290 IU/L, alanine aminotransferase at 1224 IU/L, and bilirubin of 10.0 mg/dL with direct bilirubin of 7.4 mg/dL. The patient underwent interventional radiology transjugular liver biopsy demonstrating features of drug-induced liver injury secondary to pembrolizumab therapy. He was started on steroid therapy and completed six-week course with resolution in liver enzymes. This is a unique case in which pembrolizumab-induced hepatitis occurred three years after initiation of treatment. Due to the increased use of immune checkpoint inhibitors for oncologic treatment, it is important for clinicians to recognize their immune-related adverse effects and varying timing in which these toxicities may occur.