Before any surgical treatment for a cutaneous growth is planned or carried out there must be an accurate diagnosis. I cannot go into the details of such diagnosis for the different lesions, but I wish to emphasize in the beginning of this discussion the importance of a definite diagnosis. In some instances the diagnosis can be made from the clinical appearance of the visible cutaneous lesion. Palpation of the dermal or epidermal tumor should always be combined with careful inspection, and in many cases the recognition of carcinoma is possible by palpation when inspection leaves a doubt in the surgeon's mind. When the diagnosis is impossible or doubtful from the clinical history, combined with inspection and palpation, a surgeon who has the requisite special training can differentiate the various pathologic processes by making an incision and thus exposing to the naked eye the freshly cut lesion. The operation follows immediately.