FF-OCT features of normal skin structures and tumors:
1) Normal skin structures: On a low magnification view, all skin layers including epidermis, dermis, and subcutis could be identified(Figure 1) . On a zooming-in, cellular details of each layer became evident. The epidermis appeared as a grayish linear stratified layer composed of multiple cells with a small dark nucleus and grayish cytoplasm. However, due to the difficulties in flattening the tissue edge completely on the imaging window, the epidermis could not be visualized in most of the tissues.