In the United States, lung cancer is the leading cause of cancer-related death. Candidates for tumor ablation using CyberKnife® require fiducial placement in or near the target tumor to achieve precision. Placing these reference points may lead to complications including pneumothorax and/or hemorrhage. We report a new complication: the appearance of metastatic foci along the track of the fiducial marker. Since the marker was inserted by traversing the original primary tumor, we hypothesize that malignant cells were seeded along the track. In light of this new complication, current techniques for the insertion of fiducial markers should consider a peripheral approach when possible to avoid tracking of malignant cells.