Immune Checkpoint Inhibitor-Related Pneumonitis in Renal Cell Carcinoma: Clinical Features, Mechanisms, and Lessons from Lung Cancer.

Immune checkpoint inhibitor-related pneumonitis (CIP) is an uncommon but clinically relevant toxicity in renal cell carcinoma (RCC), where immune checkpoint inhibitors are frequently used either as dual immunotherapy or in combination with VEGF-targeted tyrosine kinase inhibitors. In RCC, CIP poses specific diagnostic challenges because respiratory symptoms and computed tomography findings may overlap with pulmonary metastases, infections, thromboembolic events, heart failure, and TKI-related lung toxicity. This review summarizes the incidence of CIP across pivotal RCC trials and real-world cohorts, compares its epidemiology with non-small cell lung cancer, and discusses clinical presentation, radiological patterns, differential diagnosis, and current management strategies. Particular attention is given to RCC-specific mechanisms, including immune-mediated alveolar injury, T cell activation, cytokine dysregulation, macrophage activation, GSDME-mediated pyroptosis, and the potential contribution of VEGF pathway inhibition to pulmonary inflammation. We also review risk factors, steroid-refractory disease, second-line immunosuppression, and the unresolved issue of ICI rechallenge after pneumonitis. A better understanding of these mechanisms and clinical features may improve early recognition, guide multidisciplinary management, and support safer use of immunotherapy-based combinations in patients with RCC.