Deterioration in multifocal motor neuropathy upon treatment of immune-related adverse events of checkpoint inhibition.

Immune checkpoint inhibitors (ICIs) have significantly improved the clinical outcome in multiple types of advanced or metastatic malignancies and are prescribed increasingly. However, immune-related adverse events (irAEs) occur frequently. Here, we present a patient with multifocal motor neuropathy and melanoma, with worsening of muscle weakness upon ICI therapy and concomitant use of steroids for the treatment of hepatitis, which was considered an irAE.