Nivolumab-related lichen planus of the lip in a patient with head and neck cancer.

Immune checkpoint inhibitors (ICIs) are among the most promising drugs in the field of immuno-oncology; they represent monoclonal antibodies that modulate the effects of immune checkpoints, such as Programmed Cell Death protein 1 (PD-1) which is a co-inhibitory signal responsible for immune suppression. Dermatologic immune-related toxicity is a common type of toxicity associated with these agents. However, oral skin reactions are rare. Herein, we describe an unusual case of a patient that developed oral lichen planus during treatment with anti-PD-1 inhibitor nivolumab.