Early Onset of Severe Interstitial Pneumonitis Associated With Anti-PD-1 Immune Checkpoint Antibody After Pleurodesis

We present a case of lung adenocarcinoma with malignant pleural effusion. Nineteen days after pleurodesis using minocycline and OK-432 (picibanil), pembrolizumab monotherapy was initiated. Four days later, the patient experienced a persistent cough. Chest computed tomography showed that ground-glass opacity appeared on the same side as pleurodesis and spread bilaterally thereafter, which was diagnostic of immune checkpoint inhibitors (ICI)-related pneumonitis. As he presented a severe respiratory failure, corticosteroid therapy was administered. Two weeks later, respiratory failure completely resolved and the abnormal shadows dramatically improved. Our results indicate that severe ICI-related pneumonitis can develop within a short period after pleurodesis.