Sarcoid-Like Granulomatosis Induced by Nivolumab Treatment in a Lung Cancer Patient.

Nivolumab, an anti-PD-1 antibody, inhibits binding between PD-1 and PD-1 ligand and activates antigen-specific T cells that have become unresponsive to cancer cells. Although it is recommended as a second-line therapy in gene mutation-negative non-small-cell lung cancer, interstitial pneumonia is a well-known side effect of the drug; however, granulomatous lesions have rarely been reported. We describe the case of an 81-year-old male with cT1aN2M1b stage IV pleomorphic carcinoma of the left upper lobe of the lung. After primary treatment with carboplatin and paclitaxel, recurrence was observed in the left supraclavicular lymph node and left adrenal gland. We initiated the administration of nivolumab as a secondary treatment. Reduction was observed in the swelling of the left supraclavicular lymph node and left adrenal gland, but the tumor shadow in the right upper lobe appeared to increase. Bronchoscopy was performed, and the biopsy result showed granulomas; the findings resembled a sarcoid-like granulomatous reaction. The shadows eventually disappeared with nivolumab discontinuation; thus, we concluded that the sarcoid-like granulomatous reaction had resulted from nivolumab administration. Based on our observations, we suggest that when invasive shadows are observed after nivolumab administration, it is necessary to differentiate between disease progression and interstitial pneumonia. Moreover, the decision to reinitiate nivolumab treatment requires careful judgment in future instances of cancer recurrence.