Skin Biopsy Surgery
Skin biopsy surgery is a procedure where a small sample of skin is removed and studied under a microscope. The most common reason for doing a skin biopsy is to achieve an accurate diagnosis of a skin lesion. It is also useful to exclude specific diagnosis, for example skin cancer or malignancy. Not only do skin biopsies provide support for a clinical diagnosis, the removal of the unwanted skin lesion can also improve cosmesis. Sometimes, skin biopsies are itself a treatment modality to remove the entire skin lesion, and may be use to monitor disease progression and also useful in determining treatment response.
Skin Biopsy Techniques:
1. Punch Biopsy
The punch biopsy is one of the commonly performed techniques for skin biopsy. The instrument has a hollow and sharp circular piece that allows the removal of deeper skin structures such as the dermis or even fat. The diameter of the punch biopsy sample taken is about 3-8mm. The procedure is performed under local anaesthesia, and the wound is closed with one to two sutures after the procedure. There is low risk of significant scarring, bleeding and infection with this procedure.
2. Shave Biopsy
The shave biopsy technique is employed for more superficial skin lesions involving the epidermis. The procedure is performed under local anaesthesia where a surgical blade is used to removing the skin lesion. Its a rather fast procedure that has the advantages of not requiring any suturing. Any bleeding is stopped using electrocautery, and the wound is allowed to heal on its own (we call this healing secondary intention). The shave biopsy technique is commonly used for skin viral warts, seborrhoeic keratosis (age spots) and certain moles.
3. Incisional Biopsy
An incisional biopsy is considered when the diagnosis is in doubt, the skin lesion is too large for complete removal, or when non-surgical treatments like radiotherapy are being considered. A portion of the skin lesion is removed for histological diagnosis before planning definitive treatment. An elliptical portion of the skin is removed along the natural skin tension lines. This helps to facilitate healing, and reduces the appearance of scarring. Sutures are placed and removed timely according to the site involved.
4. Snip Excisions
As the name suggests, this procedure involves snipping a skin lesion using a pair of surgical scissors. Typically a skin lesion with a narrow base can be removed expediently under local anaesthesia, and the base is cauterised to prevent bleeding. Snip excisions are suitable for skin lesions that are polyp-like. They include skin tags, warts, seborrhoeic keratosis and certain skin cancers.
5. Excision Biopsy
An excision biopsy procedure can be both considered a therapeutic and diagnostic procedure. The entire skin lesion is removed, typically with an elliptical excision, the wounds are closed and the specimen sent for histological analysis. This is usually reserved for skin lesions or lumps to exclude precancerous and cancerous growths.
Complications of Skin Biopsy
While the majority of skin biopsies are performed safely without any significant complications, we have to be aware of what can go wrong on occasion.
- Pain: This should be minimal during the procedure when adequate anaesthetic is given. For larger skin biopsy sites, you may experience some discomfort which will respond to simple painkillers in most instances.
- Bleeding: Mild bleeding and oozing around the skin biopsy site is common. In most cases this is self limiting. However, bleeding that does not stop would require medical attention and intervention.
- Infections: The skin harbours a large amount of normal bacteria. Occasionally, the skin biopsy site can lend itself to be a port of entry for infections to occur. Infections are characterised by increase redness, warm, pain and swelling. The underarms, groin and lower limbs are more prone to infections.
- Scarring: This is common part of the healing process after your skin biopsy procedure. Scars may appear lighter (hypopigmentation), or even darker (hyperpigmentation) after the procedure. In addition, scars can be depressed (atrophic scars) or even raised (keloids and hypertrophic scars). A full discussion on the most appropriate site for skin biopsy will be undertaken during consultation.
- Maximising diagnostic outcomes of skin biopsy specimens. : Int J Dermatol. 52:72–78 2013