The discussion of the skin will be divided into three subsections: melanocytic lesions, nonmelanocytic lesions, and inflammatory (systemic) disorders. Skin biopsies are usually performed because the clinician sees a lesion, such as a mass, a rash, or a macule. However, skin biopsies are also sometimes used to diagnose systemic conditions. Usually the history is enough to direct you to one of the major three categories. Inflammatory skin conditions are not usually diagnosed by the general surgical pathologist, but a working knowledge of their classification can be very helpful. Melanocytic lesions are also more and more the exclusive domain of dermatopathologists, but any surgical pathologist should at least be able to tackle the most benign and most malignant ends of the spectrum.
The grossing of skin biopsy specimens varies a bit by the shape, size, and purpose of the excision, but for diagnostic specimens of tumors, the margins must be entirely examined in perpendicular cuts. See your grossing manual, and consult with your attending, for the best way to cut in a specimen.