20 NCCN Guidelines for Patients ® : Melanoma, 2018 2 Tests for melanoma Tumor tissue tests Tumor tissue tests To confirm if you have melanoma, a sample of tissue must be removed from the concerning spot on your skin to test for cancer cells with a microscope. This is called a biopsy. Based on the physical and skin exam, your doctor may perform a skin biopsy. There are many types of skin biopsies used for melanoma. Most biopsies try to remove all (or mostly all) of the skin lesion at the outset—to allow for the most accurate diagnosis by the pathologist. The type of biopsy you will have depends on the size and location of the concerning spot (lesion) on your skin. A skin biopsy is an important test that is needed for treatment planning. Other tests may also be needed. Types of skin biopsies include: Excisional biopsy An excisional biopsy attempts to remove the entire lesion and a small amount of normal-looking skin around the edge. The normal-looking skin removed is called the surgical margin. An excisional biopsy with 1- to 3-mm ( m illi m eter) surgical margins is preferred to confirm (diagnose) melanoma. An excisional biopsy for melanoma can be done using a surgical knife in an “elliptical” excision, where stitches (sutures) are placed. It can also be done with a deep shave/saucerization biopsy, which uses a different kind of surgical blade. Or, it can be done with a punch biopsy tool that is similar to a cookie cutter. When an elliptical excisional biopsy is done, the direction and width of the surgical cut should be done in a way that it won’t affect future treatment. If this can’t be done, your doctor may perform an incisional biopsy instead. Incisional biopsy An incisional biopsy removes only part of the lesion with a surgical knife, surgical blade, or punch biopsy. This type of biopsy may be done for a very large lesion. It may also be used for a lesion that’s in a place where it can’t be easily removed such as your face, ear, palm of your hand, or sole of your foot. Punch biopsy A punch biopsy can be excisional for some melanomas or partial for larger lesions. It uses a sharp hollow device—like a cookie cutter—to remove a small but deep sample of both skin layers. See Figure 7 . This kind of biopsy may be better for very large lesions or certain areas of the body. These areas include the face, ear, finger, toe, palm of the hand, or sole of the foot. Shave biopsy A superficial shave biopsy removes the epidermis and the top part of the dermis. The epidermis is the outer layer of skin. The dermis is the second layer of skin, under the epidermis. A superficial shave biopsy is usually not done if your doctor thinks the melanoma has grown deeply into the dermis. A deep shave biopsy, also called a “saucerization," is used to remove the entire lesion and is the most common type of excisional biopsy performed. A deep shave biopsy should not be confused with a superficial biopsy. Superficial shave biopsies are often used to remove moles that look normal and for skin diseases other than melanoma. What to expect during a skin biopsy Before a biopsy, your doctor will numb your skin with local anesthesia. Local anesthesia is medicine that results in a temporary loss of feeling in a small area of the body to prevent pain during the procedure. Tell your doctor if you’ve had any reactions to anesthesia in the past.