Skin Biopsy

Your doctor may want to obtain a sample of skin in order to diagnose diseases of the skin, such as those caused by bacteria, fungi, or other chronic skin conditions. This procedure is called a skin biopsy.

A biopsy of a lesion of the skin, such as in mole removal or tumor removal, can help your doctor tell the difference between a skin cancer and a benign, or noncancerous, lesion. The skin sample obtained during a biopsy is sent to a laboratory for examination under a microscope.

How the procedure is performed

• In an excision biopsy, the entire area of suspect skin is cut out. Excision biopsy is normally done with a scalpel. Stitches are used to close the incision.
  
  
• In a punch biopsy, a sharp cookie cutter–like instrument is used to remove a small cylinder of skin. Sometimes stitches are necessary to close this type of biopsy wound.
  
  
• The outermost part of a lesion can also be shaved off with a scalpel. This is called a shave biopsy.
  
  
• If you have a lesion on your skin that is fluid-filled and not solid, this can be evaluated with aspiration. Your doctor can put a small needle attached to a syringe into this lesion and suction out the fluid.

You should discuss with your doctor the following potential risks and complications of the biopsy procedure. You will need to sign a consent form before the procedure.

Possible risks include these:

• Bleeding from the biopsy site
  
  
• Pain
  
  
• Local reaction to the anesthetic
  
  
• Infection
  
  
• Healing problems - If you tend to form large scars (keloids), you have an increased chance of forming a scar over the biopsy site. Smoking and some chronic medical conditions such as diabetes affect the healing ability of the skin.

Skin biopsy is routinely done in the doctor’s office. You may be asked to change into a gown or remove an article of clothing so that the area of suspect skin can be more easily seen and removed.

• Tell your doctor if you have any allergies to medications, and especially if you have had any reactions to local anesthetics, such as lidocaine or Novocain, or to iodine cleaning solutions, such as Betadine.
  
  
• Inform your doctor if you are taking any medications, including over-the-counter drugs, street drugs, or herbal or nutritional supplements.
  
  
• Tell your doctor if you have any bleeding problems or if you are pregnant.

• The site of the skin biopsy is cleaned with an iodine-type solution, with alcohol, or with a sterile soap solution. After the skin has been cleaned, sterile towels are placed around the area. Do not touch this area once it has been cleaned and prepared.

• A local anesthetic, usually lidocaine, is injected into the skin to make it numb. You will feel a brief prick and stinging sensation as the medicine is injected. After the skin is numb, your doctor performs the biopsy.

• The tissue that is removed is sent to the laboratory for analysis by a pathologist.

• If needed, stitches are placed to close the wound.

• Your doctor will put a bandage over your biopsy site. Keep this bandage dry. You may be advised to wash the wound, apply antibacterial ointment, and change the bandage daily.

• If you have stitches, you need to keep the area clean and dry. Follow instructions regarding when and how to wash the wound. Stitches on the face are removed in 5-8 days. Stitches placed elsewhere on the body are removed in 10-14 days. Adhesive strips are left in place for 10-21 days.

• If you have pain at the biopsy site, talk with your doctor about medication to relieve it. In most cases, discomfort is minimal and requires nothing more than an over-the-counter pain medication.

Your doctor needs to see you again to remove the stitches and to give you the results of the pathology report.

Call your doctor if you have worsening pain, spreading redness around the site, bleeding from the wound, fever (temperature greater than 100.4°F), or other concerns.

Go to a hospital's emergency department if you have bleeding from the site that will not stop with gentle pressure, if you have a thick discharge (pus) from the wound, or if you have a high fever.

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Author: Darilyn Campbell Falck, MD, Staff Physician, Department of Emergency Medicine, Sutter Roseville Medical Center.

Coauthor(s): Troy M Falck, MD, Clinical Associate Professor of Emergency Medicine, University of California at Davis; Consulting Staff, Department of Emergency Medicine, Kaiser Permanente Medical Center-Sacramento.

Editors: Scott H Plantz, MD, FAAEM, Research Director, Assistant Professor, Department of Emergency Medicine, Mount Sinai School of Medicine; Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, ; Thomas Rebbecchi, MD, FAAEM, Program Director, Assistant Professor, Department of Emergency Medicine, University of Medicine and Dentistry of New Jersey.