Since the metastasis of the melanoma is frequently found in the regional lymph nodes in the area of the neck or the armpit or the groin, a sentinel node biopsy is performed in these localisations, i.e. the first draining lymph node is removed. To find this lymph node, a contrast agent is injected in the scar from the surgery that drains to the lymph node. From the results of the analysis the lymph node will be operated on. That is a small operation that can be done under local anaesthesia. The cut is approximately 3 cm long. Afterwards a thorough fine cell tissue analysis will show if tumour cells are already in the lymph node. Depending on the result (the extent of the tumour formation is decisive) a recommendation for a further lymph node surgery will follow.