Circulating tumor cells (CTC) are the subject of increasing interest in clinical oncology as a prognostic factor and predictor of therapeutic response. The detection of CTC by immunomagnetic method has proved its reliability and its usefulness for monitoring breast cancer, colon and prostate in the metastatic and immunomagnetic detection system (CellSearch, Veridex LLC) was approved by the FDA in these indications. However, to date there is no reliable method to detect CTCs in melanoma (CMC). Studies based on PCR amplification of mRNA by reverse specific melanoma is disappointing. Recently, a new detection system of CMC immunomagnetic was presented (CellSearch, Veridex LLC, United States). This system has the advantage of combining immunomagnetic selection step and a step of identifying by immunofluorescence. A preclinical study on serial dilutions of melanoma cells has shown encouraging results. The investigators propose a prospective study of the CellSearch system in patients with melanoma.