Need a punch biopsy? Here’s what to expect

As a dermatologist, I examine skin all day, every day. If I see something concerning on your skin, I may perform a punch biopsy to learn more about it. A punch biopsy is a minimally invasive procedure that takes a sample of your skin to check for signs of disease.    

Here, I’ll answer common questions about punch biopsies.

What does a punch biopsy test for?

Typically, we’ll do a punch biopsy if we see a rash or something suspicious on your skin, or if we suspect you may have cancer.

We give a sample of your skin to a pathologist to look at under a microscope. This can help us diagnose skin cancer or other skin conditions like moles, inflammatory skin conditions or precancerous lesions. It can also help us rule out cancer.

Why is it called a punch biopsy?

A punch biopsy is described by the tool that is used to retrieve the skin sample.

Your doctor will use a sharp, circular (punch) tool to cut deep into the tissue and then use scissors to remove a small core of skin.

What happens during a punch biopsy?

A punch biopsy is an outpatient procedure. This means it is done in a clinic or doctor’s office, and you can go home afterward.

You will be awake during the procedure. First, a nurse or doctor will inject a numbing agent like lidocaine into the skin where the biopsy will be performed. You might feel some slight discomfort when the needle is injected into your skin. After that, you should not feel any pain.

Your doctor will then use the punch tool to cut into your tissue and retrieve the skin sample. The actual sample is very small. A standard punch biopsy size ranges from about 2 to 8 millimeters.

You may get 1 or 2 stitches, depending on the size of the biopsy. Then, we’ll clean the area with an alcohol swab, apply an antibiotic ointment and cover the area with a bandage.

The entire procedure takes about 15 minutes.

How long does it take for a punch biopsy to heal?

You will need to keep the area dry for 24 hours after your punch biopsy. After that, you can begin washing the area with regular soap and water. We tell patients to apply petroleum jelly and a bandage to the area until the stitches are removed. We remove the stitches 10 to 14 days after the biopsy, depending on the location of the biopsy. After that, you can treat the area like normal.

There will be a scar any time you cut the skin. So, the biopsy will leave a scar that is the same size as the punch. In most cases, we perform 4-millimeter punch biopsies, which are very small.

When will you get the results from a punch biopsy?

Your biopsy sample will be reviewed by a pathologist, and the results will be given to your doctor. Your doctor will then share the results with you. This usually takes about a week.

It’s important to note that a punch biopsy is a technique for sampling the skin to look for disease or skin conditions. It is not meant to be a definitive treatment. Your doctor will go over the results with you and discuss the next steps, whether that’s treatment, surveillance or something else.

I always stress to patients that a punch biopsy is a minimally invasive procedure that we do often. It is not painful. And it usually takes longer for you to read over and sign the consent forms than it does for us to do the actual biopsy. So, you don’t have to be nervous about it.

Anisha Patel, M.D., is a dermatologist at MD Anderson.

Request an appointment at MD Anderson online or call 1-855-960-2943.