Large-vessel vasculitis induced by pegfilgrastim and immune checkpoint inhibitor in a patient with small-cell lung cancer.

A 75-year-old woman with stage IVB (cT3N3M1c) extensive disease small-cell lung cancer was treated with carboplatin, etoposide, and atezolizumab. Ten days after pegfilgrastim initiation, during the second chemotherapy cycle, she experienced back pain. Contrast-enhanced computed tomography revealed soft tissue thickening around the descending aorta and brachiocephalic artery. She was diagnosed with atezolizumab and pegfilgrastim-induced large-vessel vasculitis (LVV) and was treated with prednisolone, which was tapered and discontinued after 14 weeks, with no symptom recurrence. LVV should be included in the differential diagnosis of patients with nonspecific body pain when pegfilgrastim and immune checkpoint inhibitors are used in combination.