Skin biopsies are a routine procedure performed by dermatologists, removing a sample of skin to diagnose a skin lesion or mole. Done under local anesthesia in the doctor’s office, the procedure is quick and relatively painless.
First, the skin is sanitized with alcohol or another antiseptic. The assistant or doctor will inject a small amount of numbing medicine into the skin surrounding the spot to be biopsied. At most, you’ll feel a minor burning sensation for 10 seconds as the anesthesia is injected. Then, the using one of several possible surgical methods:
- Shave biopsy: The top layer of skin is shaved off with a small blade. This procedure is generally used to diagnose nonmelanoma skin conditions such as actinic keratosis and basal and squamous cell carcinoma. It is generally not used for a suspected melanoma because the sample cannot provide accurate enough melanoma staging. Stitches are not required and bleeding is minimal.
- Punch biopsy: The doctor uses a tool that looks like a tiny round cookie cutter to remove a deeper layer of the skin. If a large sample is taken, one or two stitches may be needed.
- Incisional vs. excisional biopsy: An incisional biopsy involves removing a small sample of a lesion with a scalpel. An excisional biopsy removes the entire lesion with a scalpel. Stitches are used to close the wound.
During these procedures, there is usually a small amount of bleeding. This is stopped using cautery, a small electrical current that closes the wound. Then a dressing is applied. Some biopsies require sutures but most do not. Healing occurs in 1 to 2 weeks, usually with excellent cosmetic results.
Biopsies are mainly performed to determine whether a lesion is cancerous, precancerous, or benign. By examining the biopsied specimen under a microscope and using special stains, the pathologist can give a more exact diagnosis than is possible with physical examination alone. Perhaps someday in the future we will have technology that allows us to make better diagnoses without cutting the skin, but for now skin biopsy is the gold standard for establishing a correct diagnosis.