Case reports of immune-associated pneumonia with radiological cavity formation

Checkpoint inhibitor-associated pneumonitis (CIP) is typically characterized by various radiographic patterns, including organizing pneumonia (OP), nonspecific interstitial pneumonia (NSIP), acute interstitial pneumonia (AIP), usual interstitial pneumonia (UIP), hypersensitivity pneumonitis (HP), and diffuse alveolar damage (DAD). However, cavitary lung lesions on chest CT images have rarely been described in the literature. This article reports two lung cancer patients treated with immune checkpoint inhibitors (ICIs) who developed cavitary lung lesions on chest CT. Histopathology of OP with lymphocytic infiltration was supported by multiplex immunofluorescence. After excluding infection and tumour progression, CIP was diagnosed on the basis of the patient’s history of ICI use, clinical presentation, imaging characteristics, laboratory findings, and pathological results. Both patients responded well to glucocorticoids, showing complete or near-complete resolution of cavitary lesions. After steroid discontinuation, the first patient underwent right upper lobectomy followed by adjuvant chemotherapy. After lung cancer recurrence, the patient received combined chemotherapy, immunotherapy, and radiotherapy, with no observed recurrence of CIP during follow-up. The second patient has been receiving traditional chinese medicine treatment since 2025 at another hospital. CIP rarely presents with cavitary lung lesions on CT, and careful differentiation of CIP from infectious aetiologies is essential. Empirical management may lead to treatment failure; therefore, imaging and biopsy are crucial for precise patient care.