Because skin cancer can appear on any part of the body (sun exposed and non-sun exposed areas alike), be prepared for a "true" full body skin exam in which the entire body is scanned. This includes fingers, toes, and areas normally covered by undergarments. It is important to try to not be "shy" as a skin lesion is best examined when it can be seen and felt.
If your dermatologist feels there is a lesion suspicious for cancer, a biopsy may be performed. There are several different types of skin biopsy, depending on the size of the lesion and how much skin the dermatologist feels is necessary to ascertain the diagnosis. The most common biopsy technique is called a "shave biopsy." For this procedure, the area of interest in locally anesthetized with a fast acting injection followed by removal of the lesion using a blade (razor blade or scalpel blade). These biopsies are fairly superficial and do not require stitches. This technique is the most commonly employed technique when skin cancer is suspected.
It the dermatologist needs to get deeper tissue, a "punch" biopsy may be performed. For this procedure, the area again is injected with local anesthesia and then a small round shaped "cookie cutter" (usually around 3 mm in diameter) is used to remove a small plug of skin. This technique allows the dermatologist to reach tissue as deep as the fat to send for pathology. This small hole can be closed with 1 or 2 stitches or this small hole may be left open to heal on its own.
When a lesion is very suspicious for melanoma, an excisional biopsy may be performed in which the entire lesion is excised with a small margin of normal skin. Stitches are usually required and this technique provides the pathologist a large piece of tissue in order to correctly measure the depth of the melanoma. In comparison with the excisional biopsy, an "incisional" biopsy may be performed on a very large lesion. In this case, a piece of the skin tumor is excised but much of the lesion remains. This allows for deep piece of tissue to be sent to the pathologist.
Once the biopsy is performed, the sample is sent to a pathology lab where it is processed and sliced like a loaf of bread. The pathologist then views several "slices" in order to confirm the diagnosis. One should expect the result within one to two weeks.