Abstract
BACKGROUND: Immune checkpoint inhibitor-related pneumonitis (ICI-P) is a known but potentially fatal complication in patients with underlying interstitial lung disease (ILD). However, reports of ICI-P in the postoperative setting remain scarce. CASE PRESENTATION: We present a 67-year-old man with unclassifiable interstitial pneumonia who underwent right upper lobectomy for stage IB squamous cell carcinoma. Two cycles of adjuvant nivolumab were administered. Ten days after the second cycle, the patient developed fever and progressive dyspnea. Chest CT revealed diffuse ground-glass opacities and consolidation in both lungs. Despite initial improvement with high-dose corticosteroids, respiratory failure recurred and progressed rapidly. The patient died 21 days after onset. Pathological review of the resected lung confirmed fibrosis compatible with unclassifiable interstitial pneumonia and squamous cell carcinoma. No autopsy was performed. CONCLUSION: This case highlights the potentially fatal risk of postoperative nivolumab therapy in patients with pre-existing ILD, even in the setting of unclassifiable interstitial pneumonia. Careful risk-benefit assessment is warranted when considering adjuvant immune checkpoint inhibitors in this population.