A skin biopsy involves the removal and laboratory examination of a portion of skin that appears abnormal. It can help a physician to diagnose several different skin disorders, including skin cancer, fungal or bacterial infection, or other conditions such a psoriasis or lichen planus.
One of several different types of biopsies may be performed on a patient, depending on the nature of the skin abnormality. From least invasive to most invasive, these include shave biopsy, punch biopsy, incisional biopsy and excisional biopsy.
Skin biopsies are usually performed on an outpatient basis and come with few risks. Once a skin sample has been analyzed by a pathologist, a diagnosis of the patient’s condition will be made and the patient will discuss the findings with a physician. In some cases, patients may want to seek a second opinion.
About skin biopsies
A skin biopsy is a procedure in which a portion of skin is removed from a patient and examined under a microscope. Also known as a skin lesion biopsy, it can help a physician to diagnose several different skin disorders.
Skin biopsies of moles, lesions or tumors are used to diagnose skin cancers or to confirm that a growth is noncancerous (benign). They may also be used to diagnose bacterial and fungal skin infections or other skin disorders. Skin biopsies are sometimes used to confirm a diagnosis of a skin disorder such as psoriasis or lichen planus.
There are several different types of skin biopsies. A number of factors help determine which type of biopsy is performed, including the size, type and location of the abnormality.
From least invasive to most invasive, they include:
Shave biopsy. Used to biopsy more superficial skin abnormalities, it involves use of an instrument such as a scalpel to remove the very top layers of skin. It is the least invasive form of biopsy and stitches are not required to close the wound. This method may be used when benign growths or nonmelanoma skin cancer is suspected.
Punch biopsy. Used for deeper skin abnormalities, it involves the use of a sharp, instrument resembling a cookie cutter to remove a cylinder of skin. In most cases, the sample is about the same size as a pencil eraser. When larger samples are removed, stitches may be necessary to close the wound. This method may be used to diagnose skin rashes.
Incisional biopsy. For this type of biopsy, a local anesthetic is either injected into the abnormality or applied topically. A surgeon then makes an incision with a scalpel and part of the abnormality is removed. This method may be used when melanoma skin cancer is suspected.
Excisional biopsy. During an excisional biopsy, the entire lump, spot or sore is removed. This type of biopsy may require a deeper incision than other types of biopsy. Once the entire abnormality has been removed, stitches are used to close the wound. A skin graft may be necessary to close the wound in an excisional biopsy where an extremely large or deep sample has been removed. This method may be used when tumors or melanoma skin cancer is suspected.
In some cases, a fluid-filled skin abnormality may be evaluated using a technique called aspiration. During this procedure, a physician uses a needle and syringe to suction out fluid from the lesion. As with the biopsies, the sample is then evaluated in a laboratory.
A skin biopsy is not usually performed on any infected area, unless the infected area is the cause for the biopsy.
Before and during the skin biopsy
Generally, patients need to make few preparations before a biopsy test. Preparations that may be necessary include:
Avoid vaccinations two weeks before the biopsy, as they may cause fever
Stop taking anticoagulants (medications that help prevent blood clotting) if directed by a physician
Take any preventative antibiotics prescribed by a physician prior to the biopsy
There may be additional instructions such as restrictions for eating and drinking depending on the type of anesthesia to be used in the procedure.
It is important to discuss any health issues with a physician prior to a biopsy. For example, patients should inform their physician if they are pregnant, have any allergies or have a history of bleeding problems. It is especially important to inform the physician of any history of reaction to anesthetic or to iodine-type solutions (which often are used to clean the skin prior to the procedure). Patients should also inform their physician of all medications and supplements they are taking, including over-the-counter and herbal medications. Antiinflammatory medications, aspirin and vitamin E are of particular concern because they can cause bleeding.
Before the procedure begins, the patient is usually advised about which type of procedure will be used to remove the tissue, how much tissue will be taken and what type of scar (if any) may result from the procedure.
The actual biopsy procedure can vary depending on the nature of the lesion to be tested and the type of biopsy procedure being utilized. Most biopsies are performed in a physician’s office on an outpatient basis. Prior to the procedure, the patient may be asked to change into a gown or to remove an article of clothing to facilitate access to the test site.
The skin is then cleaned with an iodine-type solution, alcohol or another substance. It is important that the patient not touch the incision area once the skin has been cleaned.
An anesthetic such as lidocaine is administered either through a local injection or a topical application. Patients may feel a brief prick or sting as the anesthetic is being administered. The actual procedure itself unfolds differently depending on the type of skin biopsy that is performed. In general, the following takes place during the biopsy:
The physician selects a scalpel, skin punch or other suitable instrument, depending on the amount of tissue to be removed.
The physician makes an incision and the tissue specimen is removed from the patient. The specimen is immediately placed in a labeled container.
Bandages, ointment or sutures are used to treat the remaining wound, as needed.
The specific part of the lesion that the biopsy is taken from is dependent on the type of lesion itself. With inflammatory lesions, a physician will usually choose to biopsy the oldest and most inflamed area. For blistering diseases, a physician usually chooses the newest vesicles and blisters because tissues from these areas return the most conclusive results.
After the skin biopsy
Following closure of the wound, the patient is instructed to keep the bandage dry, to wash the wound and apply antibacterial ointment, and to change the bandage daily. Patients who have stitches will be asked to keep the wound clean and dry. Stitches in the face are removed after five to eight days, while stitches elsewhere are removed within 10 to 14 days.
The sample that has been obtained during the biopsy is chemically treated with formalin (a combination of water and formaldehyde) or another preservative. The sample is sliced into thin sections that are placed on glass slides and stained to enhance contrast. It is then sent to a laboratory for analysis by a pathologist. Most traditional tissue analysis will yield results within three to 10 days. However, in some cases, it may take considerably longer or a second tissue sample may need to be taken.
Once pathology results become available, patients may want to discuss them with the pathologist, a dermatologist, oncologist (physician who specializes in tumors), or their own primary care physician. In some cases, the patient may also request a second opinion. If the second opinion comes from a physician at the same facility, the patient will probably not have to make any arrangements regarding medical records. Otherwise, the patient will either have to bring their pathology report and other medical records to the second expert, or have them sent by the facility that compiled the original report.
Information contained in a pathology report typically includes:
Patient, physician and specimen identification. This includes the patient’s name, hospital-issued medical record number, date when biopsy or surgery was performed and the unique number of specimens issued in the laboratory.
Clinical information. Information about the patient from the physician who removed the sample. This may include relevant medical history and special requests made to the pathologist.
Gross description. Information about the tissue that was evident without the use of a microscope. This includes things learned from looking at, measuring or feeling the tissue.
Microscopic description. Records what the pathologist observed with the aid of a microscope. Such information may include the appearance and arrangement of the cells.
Diagnosis. The pathologist’s conclusion based on everything learned in the analysis. The physician will use this diagnosis as a guideline for determining the appropriate treatment options for the patient.
Potential risks with skin biopsies
Biopsies are relatively safe procedures, but also come with risks typically associated with breaking the skin (such as infection) or surgery (including reactions to anesthetic and other surgical complications).
Patients who have a history of scarring due to skin injury may be more likely to form a scar (keloid) after a biopsy. The risk for scarring also varies by procedure. For instance, an excisional biopsy is likely to leave a scar, while scars rarely develop following a punch biopsy.
Other potential side effects associated with skin biopsies include pain (usually treated with over-the-counter pain relievers) and slow healing due to an existing medical condition such as diabetes or lifestyle factors such as smoking (which inhibits the skin’s ability to heal). Nerve damage may also occur in rare cases.
Patients should notify their physician if they experience pain that worsens, redness that expands around the biopsy site, bleeding from the wound or a fever greater than 100.4 degrees Fahrenheit (38 degrees Celsius). The following symptoms may indicate a serious medical condition and demand immediate medical attention:
Bleeding that does not stop despite gentle pressure
Swelling at the biopsy site
Thick discharge of pus from the wound
High fever
Questions for your doctor on skin biopsies
Preparing questions in advance can help patients to have more meaningful discussions with their physicians regarding their conditions. Patients may wish to ask their doctor the following questions related to skin biopsies:
Why are you recommending that I undergo a biopsy?
What type of biopsy will I have?
How much tissue will you be collecting from me?
Can my biopsy be completed as an outpatient procedure?
Will I experience any pain during the procedure? What about after?
Will I require stitches?
Are there any risks associated with the test? What complications may I develop?
How should I prepare for the biopsy?
How long will I have to wait for the results of the biopsy? Who will explain them to me?
Will the biopsy leave me with a scar?
How should I care for the wound left after the biopsy?
