LAUSR

A 68-year-old Japanese man was diagnosed with lung adenocarcinoma stage IVB. We introduced a first-line chemotherapy of four cycles of carboplatin and pemetrexed and pembrolizumab, followed by pemetrexed and pembrolizumab maintenance therapy. Approximately four months after anticancer therapy, a small nodule appeared in the right peripheral S3 lesion. After five months, the nodule was confirmed as a Mycobacterium tuberculosis (TB) nodule. We initiated anti-TB therapy without stopping pembrolizumab, and the right S3 nodule shrank immediately. This report supports the concurrent use of anti-TB treatment with an immune checkpoint inhibitor when the TB infection area is limited.