Sudden onset of severe oral and gastrointestinal lesions in a patient with lung cancer

Severe oral and gastrointestinal mucositis, though rare with immune checkpoint inhibitors, represents a life-threatening immune-related adverse events (irAE) requiring prompt recognition1,2. Key diagnostic steps include ruling out infections and inflammatory bowel disease. Early high-dose corticosteroids are the cornerstone of therapy, with escalation to biologic agents in refractory cases.