# Fusiform Excisional Biopsy

## Overview

This module describes how to perform an excisional biopsy.

## Indications

1. Suspected melanoma

2. Epidermal inclusion cysts

3. Lipomas

4. Dermal lesions

## Contraindications

1. Any lesion < 8 mm can be excised with a punch

2. Weigh up the risks and benefits in patients with a coagulopathy

3. Weigh up the risks and benefits where an unfavorable cosmetic outcome may result, or sites below the knee, where infection is common

## Patient information & consent

Always verify your patient’s identity and obtain informed consent before proceeding.

### How do I explain this procedure?

“I need to take a sample of your skin lesion to find out what it is. This method is called an excisional biopsy. I will use a small blade to cut out the whole lesion and close the wound with a few stitches afterwards. It should heal normally, but because people can sometimes form a scar, you need to sign consent for it.”

### 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.

to come out.”

### 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 stitches in x days.”

## Preparation

Prepare a trolley with equipment.

### Documentation

1. Patient notes

2. Patient labels

3. Histology forms

4. Consent form

### Equipment

1. Sterile gloves
   Sterile gloves

   Although it is considered best practice to use sterile gloves to perform minor procedures, there is mounting evidence that infection rates are similar for sterile and non-sterile glove use.

2. An apron and eye protection

3. Alcohol-based hand rub

4. 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.

5. 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.

6. A pen (surgical marker is ideal)

7. No 15 scalpel blade

8. A suture pack and suturing supplies

9. Cautery,

   silver nitrate stick
   silver nitrate stick

   Ideally, have cautery available, or otherwise 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

10. A 3-5 ml syringe, aspiration needle (ideally blunt fill), and a small injection needle

11. Lignocaine with adrenaline

12. An alcohol swab

13. A gauze dressing and transparent film dressing

14. Specimen jar and formalin

## Site and Positioning

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

Always position good lighting on the site.

### Identify Langer Lines

If you do not have a chart indicating Langer lines, you will need to 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 biopsy, orientate the long axis of the elliptical incision in line with the Langer lines.

### Incision shape

The incision is elliptical, with 3:1 ratio of length to width, and a 2 mm margin of normal skin around the lesion. A 4 mm margin is required for suspected basal cell carcinomas, and a 5 mm margin for suspected melanoma in situ.

## Procedure

Follow medical asepsis with sterile gloves.

1. Perform hand hygiene.

2. Draw the incision ellipse around the lesion with a pen or surgical marker.

3. Draw up 2-3 ml lignocaine with adrenaline. Clean the site with an alcohol swab and

   anaesthetise
   anaesthetise

   For biopsies, try to make only one puncture. Inject anaesthetic from one corner of the ellipse, aiming beneath the lesion, to either side, to the far end of the ellipse, and to the near end as you remove the needle.

   the area.

4. Open the suture pack to create a sterile field and pour skin disinfectant into the well. Open the scalpel blade, suture, silver nitrite stick and dressing onto the sterile field.

5. Perform hand hygiene and don gloves.

6. Clean
   Clean

   Start in the middle and clean in concentric circles outward.

   the skin with skin disinfectant, and drape the site.

7. Make a small incision in the corner of the ellipse using the tip of the blade. Continue the incision with the rounded edge of the blade. Repeat for the other side. Carry the incision through the full skin thickness.

8. Elevate the sample gently with forceps, then undermine the sample to the level of the subcutaneous tissue and cut it free.

9. Undermine the edges of the wound with blunt dissection to free the dermis from the subcutaneous tissue to mobilise them. For every 1 cm of closure needed, you must perform 3 cm of

   undermining
   undermining

   Use a skin hook if available to grasp the wound edges. If undermining is not done, there will be tension on the wound and this increases the risk of wound dehiscence and puckering.

   to allow the skin to stretch sufficiently.

10. Use the cautery or silver nitrate stick to stop bleeding if necessary.

11. Reapproximate the skin, trying to evert the edges and close the wound. Insert deep subcuticular interrupted

    sutures
    sutures

    Use 4-0 or 5-0 absorbable sutures.

    to reduce wound tension.

12. Close the skin with interrupted sutures.

13. Apply a gauze pad and transparent film dressing.

14. Dispose of medical waste safely.

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

16. Record completion of the procedure in patient notes.

## Troubleshooting

I am unable to approximate the edges of the incision.

The incision might not be long enough. Check the measurements indicated above, and extend the incision if necessary.

The edges of the incision pucker when I approximate them.

There is too much tension on the skin edges. Check that your incision is long enough. If so, you may need to undermine the edges some more.

The skin I am holding with the forceps while undermining is becoming bruised.

Check that you are using non-toothed forceps rather than toothed forceps. Try to apply less force on the forceps, but if this is not possible, place a piece of gauze between the skin and the forceps.

I have nicked a vessel and the bleeding won’t stop with silver nitrate

Most venous oozing stops with pressure. If not, or the bleed is from a visible vessel, clamp the vessel (or the tissue if you are unable to visualise the vessel) with artery forceps in a plane parallel to the skin. Tie an absorbable suture such as chromic under the forceps, asking an assistant to partially release the forceps while you tighten the suture before the assistant tightens their grip again. Make another tie in the suture and ask the assistant to release the forceps, but only secure the knot when you are sure that haemostasis has been achieved. If unsuccessful, perform a figure of eight suture over the area of bleeding.

## 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. Beard CJ, Ponnarasu S, Schmieder GJ. Excisional Biopsy. [Updated 2020 Sep 7]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK534835/

2. Skin Biopsy Techniques: When and How to Perform Shave and Excisional Biopsy. Consultant. 2012(52):7. Available from: https://www.consultant360.com/article/skin-biopsy-techniques-when-and-how-perform-shave-and-excisional-biopsy

3. 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; 2010:159-160.