Part 1: study of cellular infiltrate (lymphocytes) performed on large primary melanoma and cutaneous metastasis ( fresh samples) Part 2: NK cells study on metastatic regional lymph nodes ( fresh samples) and blood samples Part 3: a retrospective study of macrophages in sentinel lymph nodes and in corresponding primary melanomas Part 4: study of the cellular modulation by the chemotherapy (DTIC or cisplatin or inhibitor of B-raf) which(who) will be made on two cutaneous metastases by patient (one taken before the treatment(processing) and one taken during the evaluation after 2 or 3 cycles of treatment(processing))