by Julie J. Martin, MS
Anatomy and Physiology
The skin is the largest organ of the body. It is responsible for several important functions, including: regulating body temperature, sensing painful and pleasurable stimuli, providing a protective barrier against harmful exposures such as bacteria, toxins, and extremes of temperature, and maintaining a balance of water and electrolytes by preventing the evaporation of internal fluids.
Skin consists of two main layers: the epidermis on the surface and the dermis underneath. The thinner epidermis helps prevent most bacteria and other foreign substances from entering the body. The thicker dermis provides support for the epidermis and gives the skin its flexibility and strength. Beneath the dermis is a layer of fat cells that provides insulation and protective padding.
Aging has profound effects on the skin. As we get older, our skin gets thinner and finely wrinkled. It loses some of its elasticity and insulation, becomes more susceptible to damage from the sun and other substances, and takes longer to heal.
Reasons for Procedure
There are many types of skin conditions. Common skin disorders include: warts and moles, skin cancers and other growths, allergic reactions, bacterial or fungal infections, acne, psoriasis, and injuries and scarring.
In many cases, skin disorders affect only the skin. Other times, they indicate an underlying disease elsewhere in the body. While doctors can sometimes diagnose skin disorders just by their appearance, often they need to examine a sample of skin tissue under a microscope to make a diagnosis.
Most skin disorders can be accurately diagnosed and effectively treated without surgical removal. Many respond to topical creams or ointments, and those that do not can often be treated with medications taken by mouth. Skin changes resulting from other diseases usually resolve once the underlying problem has been treated.
Skin biopsies are performed to: diagnose infections, cancer, benign growths, and inflammatory skin disorders such as psoriasis and allergies, confirm the existence of normal skin at the edge of an area where cancer was removed, monitor treatment for certain skin disorders, remove warts, moles, skin cancers, or other growths.
Sometimes part or all of the lesion must be removed to make a diagnosis and/or treat the problem. In this simple procedure, called a biopsy, a doctor numbs the affected area and removes it with a knife, scissors, or a circular blade.
In an incisional biopsy, only a portion of the lesion is removed to make a diagnosis. In an excisional biopsy, the entire lesion is removed for the purpose of diagnosis and treatment.
In general, skin biopsies are performed in an outpatient medical office. No significant preparation is required. Your doctor will review your medical history, allergies, and the medications you take.
The location, size, and type of lesion will determine which type of biopsy should be used. There are three main types of skin biopsies: shave biopsy, punch biopsy, and excisional biopsy.
Each typically takes 5-20 minutes. Local anesthesia will be used in each type of procedure. You may feel a brief prick and a sting as the anesthetic is injected.
A shave biopsy is the least invasive technique. With a sharp scalpel or razor blade, your doctor will remove, or "shave," the top layer or layers of the skin lesion. This type of biopsy does not require stitches.
Punch biopsies are usually used for deeper skin lesions. Your doctor will rotate a circular, hollow blade around the lesion until it cuts completely through the epidermis and dermis. He or she will remove a small cylinder of skin, usually smaller than the size of a pencil eraser, containing all layers of the skin and lesion. Depending on the size of the sample, the area may or may not be closed with stitches.
An excisional biopsy is larger and deeper than a shave or punch biopsy. It is used for conditions, such as cancer, which must be entirely removed. Your doctor will go as deep as is necessary to remove all of the area visibly affected, as well as some unaffected tissue around the outside of the lesion. The incision is then closed with stitches.
After the biopsy is removed and the site closed with stitches if necessary, your doctor will apply antibiotic ointment and a bandage to the site. Some incisions will not require suture closure, and some will be closed with subcuticular, or "dissolving," sutures.
Risks and Benefits
Skin biopsies are very safe. The risks for complications are low, but include the following: infection, which is always a possibility when the skin is broken, local nerve damage, scar formation, which could be a particular concern in exposed areas such as the face; large scars, called keloids, may develop at the biopsy site in susceptible individuals.
Potential benefits of skin biopsies include: accurate diagnosis of skin disorders and/or the removal of worrisome lesions, such as cancer.
In skin biopsies, and any procedure, you and your doctor must carefully weigh the risks and benefits to determine whether it's the most appropriate procedure for you.
After the Procedure
After the biopsy, the area may be tender. Follow the wound care instructions your doctor gives you. These may include: keeping the area dry and covering it with a sterile bandage or gauze dressing for 1-2 days, applying antibiotic ointment until it is completely healed, taking acetaminophen or ibuprofen for any discomfort at the biopsy site.
Call your doctor if: you experience increased pain, redness, discharge, or swelling at the biopsy site, the biopsy site continues to bleed despite direct pressure for ten minutes.
If stitches were applied, in most cases you will be advised to come back in to have them removed. Stitches in the face are usually removed in 3-5 days. All other stitches are usually removed in 5-14 days, depending on their location. Some sutures are absorbable and do not need to be removed.
The biopsy sample will be analyzed in a laboratory and the results will be sent to your doctor within a week or two. You and your doctor will discuss the results of the biopsy and decide on any further treatment, if necessary.
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- Kasper DL, Braunwald E, Fauci AS. Harrison's Principles of Internal Medicine. 16th ed. McGraw Hill Medical Publishing Division: New York; 2005.
- National Library of Medicine, National Institutes of Health. Available at: www.nlm.nih.gov/medineplus/ency/article/003840.htm. Accessed October 2004.
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