Abstract / Summary
Abstract Background Spread through air spaces (STAS) is a pattern of invasion in lung adenocarcinoma introduced by the World Health Organization in 2015. STAS is associated with increased recurrence risk and reduced survival. Herein, we report a case of lung adenocarcinoma with STAS in which cinematic rendering provided intuitive three-dimensional visualization of satellite nodules, followed by a contralateral pulmonary lesion 18 months later harboring a de novo EGFR T790M/L858R double mutation, managed with surgery and adjuvant almonertinib. Case presentation A 53-year-old Chinese woman had a pulmonary mass incidentally discovered on chest CT during a routine medical examination. Chest CT revealed a 2.8 cm mass in the left lower lobe with multiple peritumoral satellite nodules. Cinematic rendering reconstruction clearly depicted the satellite nodules and their spatial relationship with adjacent structures. The patient underwent video-assisted thoracoscopic surgery (VATS) left lower lobectomy with mediastinal lymph node dissection. Postoperative pathology confirmed invasive lung adenocarcinoma (acinar predominant, with papillary [20%], micropapillary [15%], and focal poorly differentiated [5%] components) with STAS, pathological stage pT1cN0cM0 (AJCC 9th edition). No adjuvant therapy was administered. Follow-up chest CT every 6 months revealed a new 0.6 cm nodule in the right middle lobe 18 months postoperatively. The patient underwent VATS right middle lobectomy with mediastinal lymph node dissection. Pathology confirmed a second invasive lung adenocarcinoma (acinar 40%, papillary 40%, micropapillary 20%, grade 3), stage pT1aN0cM0. Genetic testing revealed EGFR T790M (exon 20) and L858R (exon 21) double mutation. The patient was started on adjuvant almonertinib (110 mg daily) and remained recurrence-free at 20 months of almonertinib therapy. Conclusions This case demonstrates that peritumoral satellite nodules on CT reliably indicate STAS, and STAS-positive patients require vigilant surveillance for metachronous pulmonary lesions. Cinematic rendering provides intuitive visualization of STAS-related satellite nodules, aiding surgical planning. The de novo EGFR T790M/L858R double mutation in the metachronous lesion raises important considerations regarding tumor clonality, possible germline EGFR T790M, and the role of third-generation EGFR-TKIs as adjuvant therapy.