What happened, in summary

A 70-year-old man with a 40-year smoking history was admitted for evaluation of bilateral pulmonary nodules. He had developed chest discomfort, cough, and white sputum about 3 years earlier, and symptoms had worsened in the 2 months before diagnosis. High-resolution CT showed a 34 x 24 mm ground-glass opacity in the left upper lobe and a 19 x 13 mm solid nodule in the right lower lobe, along with other small calcified lung shadows. PET/CT suggested the left upper-lobe lesion was malignant and showed mild uptake in bilateral hilar lymph nodes. In February 2023, he underwent left upper-lobe lobectomy with mediastinal lymph-node dissection. Four months later, he had a right lower-lobe wedge resection. Pathology confirmed that both nodules were moderately differentiated invasive lung adenocarcinomas, with no vascular tumor thrombus, perineural invasion, or lymph-node metastasis. The 2 tumors had different histologic and molecular profiles: the left tumor showed acinar and papillary features with MET exon 14 skipping and PIK3CA p.E545K, while the right tumor showed acinar and lepidic features with a KRAS exon 2 p.G12S/D mutation. These differences supported independent clonal origins rather than one tumor spreading to the other lung. He did not receive a MET inhibitor or other systemic treatment after surgery. Follow-up in October 2023 showed normalized oncologic markers, negative tests for 7 lung cancer-specific autoantibodies, and improved lung clarity on HRCT. He recovered well and had no evidence of recurrence for 1 year. Pathology also found no vascular tumor thrombus or perineural invasion, supporting surgery alone rather than adjuvant systemic therapy.