Case Report of Acute Central Airway Obstruction Induced by Anti-PD-1 Sintilimab: Clinical Presentation and Review.

Immune checkpoint inhibitors (ICIs), such as sintilimab, have revolutionized non-small cell lung cancer (NSCLC) treatment but can trigger immune-related adverse events (irAEs). While pneumonitis is well documented, central airway obstruction (CAO) due to immune-mediated necrosis is an extremely rare and life-threatening phenotype that poses significant diagnostic challenges. A patient with recurrent squamous cell carcinoma of the lung achieved partial remission after two cycles of sintilimab combined with chemotherapy. However, 48 h after the third cycle, the patient developed acute, severe dyspnea and hypoxemia. Emergency bronchoscopy revealed extensive necrotic material occluding the right main bronchus and carina. Pathological analysis indicated lymphocytic infiltration with necrosis, while microbiological tests were negative for pathogens. Given the temporal relationship, exclusion of alternative etiologies, and response to corticosteroids, the event was considered probable sintilimab-related acute necrotizing CAO. Immediate interventional bronchoscopy with cryoablation was performed to restore airway patency. This was followed by a short course of systemic corticosteroids (methylprednisolone, then a prednisone taper). The patient's symptoms resolved completely, and follow-up bronchoscopies confirmed mucosal healing without recurrence of stenosis or necrosis. This case highlights a distinct, underrecognized pulmonary irAE manifesting as acute central airway necrosis. Although a definitive causal relationship cannot be established from a single case, the clinical course strongly suggests a probable association with sintilimab.