Severe Legionella pneumonia mimicking immune-related pneumonitis after chemoimmunotherapy for lung cancer: a case report

In the era of chemoimmunotherapy, the presence of pulmonary ground-glass interstitial lesions should prompt consideration not only of immune checkpoint inhibitor-related pneumonia (ICI-P) but also of infections caused by uncommon pathogens such as <i>Legionella</i>, particularly when there is no significant improvement after corticosteroid therapy. It is necessary to consider applying advanced molecular diagnostic techniques such as targeted next-generation sequencing (tNGS) as early as possible to make a clear diagnosis of the pathogen and guide individualized treatment.