A case of relapsing polychondritis after long-term administration of nivolumab in lung squamous cell carcinoma

Abstract

Background. Although various immune-related adverse events (irAEs) have been reported following the administration of immune-checkpoint inhibitors, relapsing polychondritis (RP) is an extremely rare one. Case. A 61-year-old man was diagnosed with lung squamous cell cancer (cT2bN3M0, cStage IIIB) with a high tumor expression of PD-L1 (tumor proportion score >90%). He underwent 6 courses of pembrolizumab as first-line chemotherapy and showed a partial response. However, we had to discontinue this treatment owing to the occurrence of intractable pneumothorax. After he recovered from the pneumothorax, we conducted second-line chemotherapy with carboplatin and nab-paclitaxel and third-line chemotherapy with 29 courses of nivolumab, resulting in a partial response. Subsequently, he complained of spontaneous tenderness of the bilateral ribs and dyspnea in the supine position. There were no abnormal findings on either abdominal computed tomography (CT), gastrointestinal endoscopy, or colonoscopy. However, fluorodeoxyglucose (FDG)-positron emission tomography (PET)/CT revealed the prominent accumulation of FDG in the tracheobronchial trees, costal cartilages, and nasal septum. Furthermore, we noted an increased thickness of the bronchial wall on contrast-enhanced CT. A biopsy of the costal cartilage revealed lymphocyte infiltration and granuloma reaction. Given these findings, we diagnosed him with RP. After the administration of corticosteroids, the thickness of the bronchial wall decreased, and his subjective symptoms improved. Conclusion. We experienced a rare case of RP induced by nivolumab. FDG-PET/CT was useful in its diagnosis.