在接受免疫检查点抑制剂 (ICIs) 癌症治疗的患者中，有 1.5%-22% 的患者出现类似风湿病的免疫相关不良事件 (irAE)。复发性多软骨炎（RP）是一种罕见的自身免疫性疾病，主要涉及耳廓、鼻和气道软骨炎症。然而，关于 RP 作为 irAE 的知识却很少。 Pembrolizumab 是一种调节程序性细胞死亡蛋白-1 (PD-1) 的 ICI，用于治疗无法通过手术或放疗治愈的癌症患者。我们报告了第一例帕博利珠单抗诱导的 RP，其中孤立性耳廓病变无需免疫抑制剂即可痊愈。一名 49 岁男性患有下唇癌，接受了手术切除和重建。组织病理学检查证实了鳞状细胞癌的诊断。由于术后 6 个月出现多发转移，导致癌症无法手术，因此开始使用派姆单抗，改善淋巴结受累。然而4个月后，患者双耳出现快速进行性肿胀和疼痛。虽然未检测到病原体，但 C 反应蛋白水平升高 (11.21 mg/dL)。计算机断层扫描（CT）显示双侧耳廓肿胀；右耳廓活检显示周围肉芽组织浸润导致软骨破坏。由于在开始使用帕博利珠单抗之前未观察到这些特征性发现，因此我们临床诊断该患者为帕博利珠单抗诱发的 RP。停药 1 个月后，耳廓肿胀自然消退。 18F-氟脱氧葡萄糖（18F-FDG）-正电子发射断层扫描/CT显示耳廓病变减少时没有 18F-FDG 摄取。重新给予派姆单抗以维持抗肿瘤免疫时，双耳再次肿胀，考虑到气管支气管软骨炎的风险，派姆单抗改用紫杉醇。尽管没有观察到耳廓软骨炎复发，但患者在服用紫杉醇后 8 个月因癌症进展而死亡。接受抗 PD-1 治疗的患者中，RP 可作为风湿性 irAE 发生，文献综述和回顾性分析表明，PD-1 抑制诱导的 RP 是不寻常且非典型的。版权所有 © 日本医学会。

Immune-related adverse events (irAEs) mimicking rheumatic diseases are observed in 1.5%-22% of patients receiving cancer therapy with immune checkpoint inhibitors (ICIs). Relapsing polychondritis (RP) is a rare autoimmune disease mainly involving auricle, nose, and airway cartilage inflammation. However, knowledge regarding RP as an irAE is scarce. Pembrolizumab, a type of ICI that regulates the programmed cell death protein-1 (PD-1), is used in patients whose cancer cannot be cured with surgery or radiation therapy. We report the first case of pembrolizumab-induced RP with isolated auricular lesions resolved without immunosuppressants. A 49-year-old man with lower lip cancer underwent surgical resection followed by reconstruction. Histopathological investigation confirmed the diagnosis of squamous cell carcinoma. Since multiple metastases 6 months post-surgery rendered the carcinoma inoperative, pembrolizumab was initiated, improving lymph node involvement. However, 4 months later, the patient developed rapidly progressive swelling and pain in both auricles. While no pathogen was detected, C-reactive protein levels were elevated (11.21 mg/dL). Computed tomography (CT) showed swelling of the bilateral auricles; the biopsy of the right auricle revealed cartilage destruction by infiltration of surrounding granulation tissue. Since these characteristic findings were not observed before pembrolizumab was initiated, we clinically diagnosed the patient with RP induced by pembrolizumab. The swelling of the auricles resolved spontaneously 1 month after pembrolizumab discontinuation. 18F-fluorodeoxyglucose (18F-FDG)-positron emission tomography/CT revealed no 18F-FDG uptake in reduced auricular lesions. On re-administration of pembrolizumab to maintain antitumor immunity, both auricles swelled again, and pembrolizumab was switched to paclitaxel, considering the risk of tracheobronchial chondritis. Although no recurrence of auricular chondritis was observed, the patient died from cancer progression 8 months after paclitaxel administration. RP can occur as a rheumatic irAE in patients receiving anti-PD-1 therapy, and a literature review with retrospective analysis indicates that PD-1 inhibition-induced RP is unusual and atypical.Copyright © Japan Medical Association.