Metastasis is the most common form of malignant lung tumor. Radiofrequency ablation (RFA) is a new treatment for single pulmonary tumors. However, RFA can be complicated by iatrogenic and parietal recurrence. We report the case of a 67-year-old man with a single pulmonary metastasis from colorectal cancer diagnosed two years previously and locally controlled by left hemi-colectomy. The metastasis was treated by RFA. Four months after the procedure, a positron emission tomography scan revealed parietal chest contamination. Surgical resection enabled the diagnosis of parietal tumor expansion and confirmed successful treatment of the initial metastasis. This case highlights the risk of iatrogenic parietal contamination after RFA. To our knowledge no similar case has been published to date. The most appropriate steps to prevent this type of complication still have to be defined.