What are the steps and considerations for performing a skin biopsy?

From the Guidelines

Performing a skin biopsy requires careful preparation, proper technique, and appropriate follow-up care, with the most recent and highest quality study recommending excisional biopsy with 1-3 mm margins as the preferred method for diagnosing skin cancer 1. When performing a skin biopsy, the following steps should be taken:

• Select the biopsy type based on the lesion characteristics: punch biopsy (2-6mm circular sample) for small lesions, shave biopsy for raised lesions, or excisional biopsy for complete removal of suspicious growths.
• Obtain informed consent and gather supplies including sterile gloves, antiseptic solution, local anesthetic (typically 1-2% lidocaine with epinephrine), biopsy tools, gauze, specimen container with formalin, and suture materials.
• Clean the area with antiseptic solution and administer local anesthetic, waiting 5-10 minutes for full effect.
• For a punch biopsy, apply the punch tool perpendicular to the skin with gentle downward pressure and twisting motion until reaching subcutaneous fat.
• Carefully lift the specimen with forceps and snip at the base with scissors.
• Control bleeding with pressure or electrocautery, then close larger wounds (>4mm) with simple interrupted sutures using 4-0 or 5-0 non-absorbable material.
• Place the specimen in formalin immediately and label with patient information and biopsy site. Some key considerations when performing a skin biopsy include:
• Selecting the most representative area of the lesion
• Avoiding distortion of the specimen during collection
• Ensuring proper specimen handling to preserve diagnostic features
• Providing wound care instructions, including keeping the site clean, applying petroleum jelly and a bandage for 24-48 hours, and watching for signs of infection
• Scheduling appropriate follow-up for suture removal (7-14 days) and to discuss pathology results, as recommended by recent studies 1.

From the Research

Steps for Performing a Skin Biopsy

• The procedure involves the use of a circular blade that is rotated down through the epidermis and dermis, and into the subcutaneous fat, yielding a 3- to 4-mm cylindrical core of tissue sample 2.
• Stretching the skin perpendicular to the lines of least skin tension before incision results in an elliptical-shaped wound, allowing for easier closure by a single suture 2.
• Once the specimen is obtained, caution must be used in handling it to avoid crush artifact 2.
• The procedures used most often for office-based skin biopsies are two types of shave biopsies, punch biopsy, and elliptical biopsy performed with a scalpel 3.

Considerations for Performing a Skin Biopsy

• Skin biopsy is a safe, easy and out-patient procedure of diagnostic and academic relevance, but complications such as bleeding, infection and scarring may occasionally be encountered 4.
• It is not necessary to discontinue anticoagulants before office-based skin biopsy is performed or to administer topical or systemic antibiotics 3.
• When sutures are used for wound closure, it is important for the sutures to have appropriate tensile strength, and multifilament sutures should be avoided in areas prone to infection, such as the feet 3.
• An important complication of skin biopsy is the development of hypertrophic and keloid scars, which are more common among patients with dark skin, and injection of triamcinolone or verapamil into a maturing scar can minimize the possibility of hypertrophic and keloid scars 3.

Types of Skin Biopsy

• Punch biopsy is considered the primary technique for obtaining diagnostic full-thickness skin specimens 2.
• Shave and punch biopsies are essential procedures for physicians who manage skin conditions, and can diagnose questionable dermatologic lesions, including possible malignancies 5.
• Tangential shave biopsy is superficial and best suited to small, raised, benign lesions, while saucerization shave biopsy is deeper and is used for excisional biopsy of atypical nevi, for squamous and basal cell carcinomas, and as initial biopsy for suspected melanoma 3.
• Elliptical biopsy using a scalpel is reserved for larger lesions not amenable to shave or punch biopsies 3.