# Punch Biopsy

## Overview

This module describes how to use a punch biopsy to take an

incisional

incisional

removes part of the lesion

or

excisional

excisional

removes the entire lesion

sample of the skin, including the epidermis, dermis, and subcutaneous tissue.

## Indications

Because punch biopsies sample deeper tissues, they are most suited to diagnosing lesions where dermal or subcutaneous tissue is required.

## Contraindications

## Patient information and consent

### How do I explain this procedure?

“I need to take a sample of your skin lesion to find out what it is. The method is called a punch biopsy. I use a punch tool to take a small, round sample of the skin and underlying tissue. I will close the wound with a stitch afterwards.”

### What can my patient expect?

“I will give you an injection so that you will not feel me taking the sample. You may feel tugging and working in the area, but it will not be painful. The test results may take a few days

or longer

or longer

Histology often takes 6 weeks for results. If urgent, call the pathologist directly to discuss and expedite.

after which I will contact you with the diagnosis.”

### What is my patient’s role?

“Let me know if you have any allergies or a bleeding tendency, or use blood thinners. Fearing blood or needles is normal, but tell me if you have fainted from it. Keep still while I take the sample. Afterwards, keep the plaster on for at least a day, and come back to remove the stitch in x days.”

## Preparation

Prepare a trolley with equipment.

### Documentation

### Equipment

## Site and Positioning

The patient should be positioned reclining or supine with the lesion within easy reach.

### Identify the area to be sampled

When there are several areas to choose from, select an early lesion or one that is well advanced. Sample larger lesions near the edge of an advancing border. Include the most raised or darkly pigmented area.

### Identify Langer Lines

If you do not have a chart indicating

Langer lines

Langer lines

, determine in which direction these lines lie at the biopsy site. Pinch the skin at the site, trying in two directions perpendicular to each other. The direction which produces the most wrinkles is the direction of the Langer lines in this area. When performing the punch biopsy, stretch the skin in a direction perpendicular to these lines, so that the end result is an elliptical wound aligned with the lines. This facilitates easy closure or healing by secondary intent.

## Procedure

Follow medical asepsis with non-sterile gloves.

## Troubleshooting

I’ve encountered pigmented tissue at the base of the specimen.

Continue to punch well into the subcutaneous fat. Ensure that you biopsy the entire depth of the lesion, since depth in mm is the major prognostic feature of stage I and II melanoma.

## Risks

## References