Staple-line-associated lung adenocarcinoma years after video-assisted thoracoscopic surgical bullectomy for pneumothorax.

Lung scar carcinoma (LSC) arising along a surgical staple line years after resection of a benign lesion is exceptionally rare. We report a 77-year-old man with severe emphysema who underwent video-assisted thoracoscopic bullectomy. Surveillance chest computed tomography showed a progressively enlarging spiculated mass centered on the right upper lobe staple line with high 2-deoxy-2-[fluorine-18]fluoro-D-glucose (18F-FDG) uptake and mildly elevated carcinoembryonic antigen levels. Bronchoscopic biopsy confirmed adenocarcinoma, and targeted sequencing revealed no oncogenic driver alterations. The clinical stage was cT2aN0M0. Because pulmonary function was prohibitive, a multidisciplinary team selected stereotactic body radiotherapy (SBRT) (56 Gy in eight fractions). Follow-up imaging demonstrated a partial response according to RECIST 1.1 with reduced FDG avidity and no acute toxicity. The patient remains under active surveillance without progression. This case highlights the difficulty of distinguishing malignant staple line thickening from postoperative or infectious changes and illustrates SBRT as an effective, organ-preserving option in medically inoperable LSC.