A small sample of skin tissue is removed, under local anesthesia, for examination under a microscope; the specimen is usually taken from an area that appears altered because of disease (lesion). Three different techniques may be used:
Shave biopsy removes the outer layer of a lesion with a sharp scalpel.
Punch biopsy uses a hollow, cylindrical instrument, called a punch, to remove a circular core of tissue from the center of a lesion.
Excisional biopsy is the removal of the entire lesion with a surgical knife; this procedure may also function as a primary treatment.
Purpose of the Skin Biopsy
- To identify benign and malignant (cancerous) growths
- To diagnose chronic bacterial and fungal skin infections
- To diagnose inflammatory and autoimmune skin disorders, including psoriasis, systemic lupus erythematosus, and autoimmune blistering diseases
- To serve as a form of therapy, by removing skin cancers, warts, moles, and other growths
- To diagnose many other conditions, including lupus and other less common conditions
- To confirm that the skin around where a tumor was removed is normal and healthy
- To monitor how effective a treatment is
Who Performs It
- A dermatologist, a plastic surgeon, or another physician
- Results are more likely to be inconclusive if a small tissue sample is taken in an effort to reduce the scar size, or if the biopsy site was not selected properly.
Before the Skin Biopsy
- Tell your doctor or nurse if you have an allergy to Betadine, iodine or shellfish.
- Tell your doctor if you are taking any medicine or supplements, as some of these may increase your risk of bleeding.
- Tell your doctor if you have any bleeding problems.
- Inform your doctor of any drugs you are currently taking and whether you have any allergies to medication.
- If you are scheduled to have a large biopsy, such as an excisional biopsy, your doctor will advise you to discontinue any drugs (such as aspirin or ibuprofen) and herbal remedies that may promote bleeding, as well as alcohol, a few days before the procedure.
What You Experience
- After injecting a local anesthetic into the biopsy site to numb the area, the doctor removes the tissue sample.
- If a large tissue sample is obtained (which is most common in excisional biopsies and some punch biopsies), the area may be closed with stitches.
- In cases where a large lesion (such as a cancer) is removed, a skin graft may be needed.
- The biopsy usually takes about 5 to 10 minutes, but may take as long as 60 minutes if the procedure is complex.
Risks and Complications
- Skin biopsy leaves a scar, which can range from slight to obvious. Let your doctor know before surgery if you tend to form large scars, or keloids, in response to a skin injury; he or she will follow postoperative measures that may reduce scarring.
- Rarely, infection may occur after the biopsy, or nerve damage may develop if the biopsy is deep.
After the Skin Biopsy
- The doctor will check the biopsy site for bleeding, and may give you pain-relieving medication if needed.
- If no stitches were required, an antibiotic ointment is applied and a dressing placed over the site. The doctor will advise you to clean the area, reapply the ointment, and change the dressing at least once a day until healing occurs, usually in 5 to 28 days.
- If stitches were necessary, the doctor may leave the dressing in place or periodically change it until the stitches are removed, usually 3 to 14 days later. During this time, keep the biopsy site clean and dry. You may also have to avoid exercise or heavy lifting for several weeks.
- The skin specimen is sent to a pathology laboratory and examined under a microscope for abnormal changes.
- If the biopsy reveals cancerous cells, treatment to completely remove the malignant lesion will be instituted (unless excisional biopsy was already performed to remove the entire lesion).
- If the biopsy findings indicate the presence of a specific autoimmune or inflammatory disorder, appropriate therapy will be started.
- If the biopsy findings are inconclusive, an additional biopsy may be needed.
The Johns Hopkins Consumer Guide to Medical Tests
Simeon Margolis, M.D., Ph.D., Medical Editor
Updated by Remedy Health Media