Drug-induced oral lichenoid reaction during nivolumab therapy.

Oral lichenoid reaction, an immune-related adverse event of immunotherapy, has been reported in very few patients receiving anti-programmed cell death receptor-1 (anti-PD-1) therapy. Here, we describe a case of severe stomatitis (grade ≥3 by the Common Terminology Criteria for Adverse Events, version 4.0) accompanied by pharyngolaryngitis that was observed in a patient receiving nivolumab therapy. The stomatitis was diagnosed as drug-induced lichenoid reaction. Nivolumab therapy was discontinued, and the patient was administered systemic prednisolone (1mg/kg). Most of the patient's mucosal changes in the oral cavity and pharyngolarynx resolved within approximately 3 weeks after starting the prednisolone. Clinicians should be aware that severe oral lichenoid reactions can occur in patients receiving anti-PD-1 therapy.