It is uncommon for a cancer to be diagnosed because of skin metastases. Cutaneous metastases as initial manifestation of internal neoplasias, represent only 0.8% of total cases and implies, in general, a very advanced grade of the disease and short survival. When skin metastases of an unknown primary site appear, lung cancer is the first option to be discarded in case of men, and breast cancer in case of women. Lung cancer spreads to the skin in 2.8-8.7% of the cases, in advanced phases of the disease, although just in 7-23.8% of the cases, cutaneous metastases appear as first manifestation of the primary tumor. Sometimes, a complete examination to discover the tumor reveals no metastases elsewhere. © FESEO 2006.