# 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.

1. Inflammatory lesions & panniculitis

2. Bullous lesions

3. Large dysplastic or complex nevi that cannot be excised

4. Scalp or hair follicle samples

## Contraindications

1. Sites with superficial large vessels or other vital structures

2. Lesions better sampled by other methods

3. Lesions that do not require sampling for diagnosis and management e.g. classical atopic eczema

4. Weigh up the risks and benefits in patients with coagulopathy

## 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

1. Patient notes

2. Patient labels

3. Histology forms

### Equipment

1. Non-sterile gloves

2. Alcohol-based hand rub

3. Sharps container
   Sharps container

   If a sharps container is not within arm's length, use a kidney dish or other hard container to temporarily hold used sharps and to carry them to the sharps container for disposal.

4. Skin disinfectant
   Skin disinfectant

   Commonly used preparations include 0.5-2% chlorhexidine in 70% alcohol (Steriprep), or 10% povidone iodine. There is no consensus on the superiority of one agent above another. Caution: chlorhexidine solutions may be associated with burns and skin breakdown in infants < 2 months old.

5. A punch biopsy tool
   A punch biopsy tool

   Select the right size for the lesion you are sampling. 2-6 mm are most commonly used.

6. A suture pack and suturing supplies

7. Silver nitrate stick
   Silver nitrate stick

   Ideally, have cautery available, Monsel's solution (ferric subsulfate) and aluminium chloride. Monsel's solution can rarely cause tattooing. Aluminium chloride slows wound healing. Silver nitrate can also cause tattooing.

   or other haemostatic agents

8. A 3-5 ml syringe, aspiration needle (preferably blunt fill), and an injection needle

9. Lignocaine with adrenaline

10. An alcohol swab

11. A gauze dressing and transparent film dressing

12. Specimen jar and formalin

## 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.

1. Draw up 2-3 ml lignocaine with adrenaline.

2. Open the suture pack and pour skin disinfectant into the well.

3. Perform hand hygiene and don gloves.

4. Clean
   Clean

   Start in the middle and clean in concentric circles outward.

   the skin with cleaning solution.

5. Anaesthetise the site with lignocaine.

6. Tense the skin perpendicular to Langer lines with your non-dominant hand.

7. Insert the punch
   Insert the punch

   Insert until there is a loss of skin tension, indicating full thickness insertion.
   You want to get to at least the level of the dermal-subcutaneous tissue interface.

   , using rotational movements.

8. Remove the punch.

9. Elevate the sample using the

   tip of the anaesthesia needle
   tip of the anaesthesia needle

   Forceps should not be used as they create crush artifact.

   with your non-dominant hand.

10. Cut off the sample with scissors below the level of the dermis.

11. Use the silver nitrate stick to stop bleeding if necessary.

12. If necessary
    If necessary

    Generally only necessary in cosmetically critical sites, or in punch biopsies of 6 mm or greater in diameter. A 5-0 suture is usually used in non-facial areas and a 6-0 in facial areas.

    , insert a suture to close the wound.

13. Apply a gauze pad and transparent film dressing.

14. Label a specimen jar of formalin, and send the sample in it to the laboratory with a histology form.

15. Dispose of medical waste safely.

16. Record completion of the procedure in patient notes.

## 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

1. Local hematoma, pain, or excessive bleeding at the site

2. Injury to nerves and other local structures

3. Infection at the site

4. Scarring

5. Sharps injury to healthcare personnel

6. Vasovagal response (fainting)

## References

1. Ramsey ML, Rostami S. Skin Biopsy. [Updated 2021 Jun 4]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK470457/

2. Pickett H. Shave and punch biopsy for skin lesions. Am Fam Physician. 2011;84(9):995-1002.

3. Zuber TJ. Punch biopsy of the skin. Am Fam Physician. 2002;65(6):1155-1164.

4. Hellenberg D. How to do a skin biopsy, cryotherapy and electrotherapy. In: Mash B, Blitz-Lindeque J, eds. South African Family Practice Manual. 2nd ed. Pretoria: Van Schaik Publishers; 2010:160-161.