A 58-year-old man with melanoma treated with ipilimumab/nivolumab presented with pain, limited joint mobility, and proximal weakness without oculobulbar weakness, dyspnea, or rash. EMG demonstrated positive sharp waves, fibrillations, and myopathic units. Extremity MRI showed diffuse fascial and mild muscle enhancement consistent with fasciitis/mild myositis (Figure). Creatinine kinase was normal. PET-CT demonstrated diffusely fluorodeoxyglucose-avid lymph nodes and muscles; lymph node biopsy revealed granulomatous inflammation suggesting immune checkpoint inhibitor-related inflammatory reaction. Biceps biopsy demonstrated perifascicular atrophy (PA) and fascial/perimysial perivascular inflammation (Figure).

一名 58 岁黑色素瘤男性患者接受了易普利姆玛/纳武利尤单抗治疗，表现为疼痛、关节活动受限和近端无力，但无眼球无力、呼吸困难或皮疹。肌电图显示阳性尖波、纤颤和肌病单位。四肢 MRI 显示弥漫性筋膜和轻度肌肉强化，符合筋膜炎/轻度肌炎（图）。肌酐激酶正常。PET-CT 显示弥漫性富含氟脱氧葡萄糖的淋巴结和肌肉；淋巴结活检显示肉芽肿性炎症，提示免疫检查点抑制剂相关炎症反应。二头肌活检显示束周萎缩 (PA) 和筋膜/肌周血管周围炎症（图）。