Tracheobronchial chondritis is a rare immune-related adverse event (irAE) associated with immune checkpoint inhibitors. We report a case wherein tracheobronchial chondritis occurred while administering nivolumab for recurrent hypopharyngeal squamous cell carcinoma (SCC) in a man diagnosed with T2N3bM0 stage IVB hypopharyngeal SCC. After treatment with cisplatin and radiotherapy followed by left and right neck dissection, local recurrence was observed in the hypopharynx. Because of the difficulty of salvage surgery, we administered 240 mg/body of nivolumab. After 9 cycles of nivolumab, the patient was judged to have complete response. After 10 cycles, he had cough and sputum, for which prompting us to perform imaging tests. Computed tomography (CT) showed edematous thickening around the trachea and bilateral bronchi and elevated amounts of adjacent subcutaneous fat tissue. Positron emission tomography-CT showed diffuse fluorodeoxyglucose uptake in the trachea and bilateral bronchi, bronchial endoscopy showed redness and swelling throughout the bronchi, and biopsy showed partial mucosal erosion, inflammatory cell (lymphocyte) infiltration, interstitial edema, and desmoplasia. The patient was diagnosed with tracheobronchial chondritis as an irAE resulting from administering anti-programmed death-1 monoclonal antibody. After four-day prednisolone treatment, his cough and sputum disappeared; after two weeks, tracheobronchial chondritis no longer appeared on CT.
