CT-guided methylene blue staining to facilitate thoracoscopic resection of intermediate-to-deep pulmonary metastases in pediatric patients

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Purpose Thoracoscopic resection of pulmonary metastases offers a minimally-invasive approach but requires preoperative localization due to absent tactile feedback. CT-guided methylene blue staining (MBS) was implemented to facilitate resection of pulmonary metastases, including intermediate-to-deep lesions. Methods We retrospectively analyzed pediatric patients (0–18 years) undergoing resection of pulmonary metastases (2007–2024). Lesion depth was classified as superficial (≤ 10 mm), intermediate (11–20 mm), or deep (> 20 mm). Primary endpoint was completeness of resection; secondary endpoints included perioperative and oncological outcomes. Subgroup analysis included patients with ≤ 2 pulmonary metastases. Results Fifty-eight resections in 43 patients were included: 49 open, and 9 thoracoscopic following CT-guided MBS. Eleven lesions were stained prior to thoracoscopic resection: three superficial, seven intermediate, one deep lesion. All were resected with negative margins, without complications. Thoracoscopy following CT-guided MBS was associated with shorter operative times (65 vs. 157 min, p = 0.01), hospital stay (4.0 vs. 5.6 days, p = 0.01), and time-to-chemotherapy-resumption (2.25 vs. 18.6 days, p = 0.01). No differences were observed in pulmonary recurrence, disease-free interval, or six-month-survival. Conclusion In pediatric patients with up to two pulmonary metastases, CT-guided methylene blue staining provided feasible preoperative localization, facilitating thoracoscopic wedge resection of superficial, intermediate and deep lesions without complications. Prospective multicenter studies should further evaluate efficacy and inclusion criteria.