Background: Video-assisted thoracoscopic surgery (VATS) is an increasingly used technique to treat patients with pulmonary metastases, but it does not usually afford lung palpation. Methods: A retrospective study on patients with lesions defined as 'VATA-able' who underwent open metastasectomy via thoracotomy. All patients underwent 64-slice helical CT scan with intravenous contrast using 5 mm cuts and integrated FDG-PET/CT. Unsuspected malignant pulmonary nodules that were palpitated and removed, and were not imaged pre operatively were defined as 'malignant nodules' and would have been missed by VATS metastasectomy. Results: From January 2004 to December 2005, 57 patients had 'VAT-able' metastatic pulmonary lesions that were resected via thoracotomy by one thoracic surgeon. Twenty-one (37%) patients had non-imaged pulmonary nodules that were discovered only by bi-manual palpation and would have been missed by VATS metastasectomy, but these nodules were only malignant in 10 (18%) patients. The median size of the non-imaged pulmonary nodule was 0.7 cm (range, 0.4-0.8 cm). Colorectal carcinoma was the most common tumor requiring metastasectomy. Non-imaged malignant pulmonary nodules were most frequently found in patients with leiyomyosarcoma and osteosarcoma (three of eight patients in both). Conclusion: Metastasectomy via open thoracotomy, which affords bi-manual lung palpation of the entire ipsilateral lung, may discover non-imaged malignant pulmonary metastases in 18% of patients who have had a previously treated solid organ cancer and have at least one imaged metastatic lesion in the lung. The clinical impact of these findings is unknown. A prospective study to further examine this issue is underway. © 2009 European Association for Cardio-Thoracic Surgery.