9 The Shave Biopsy

The shave biopsy is one of the most useful approaches for obtaining tissue for diagnostic purposes and for the removal of benign surface neoplasms. It is especially fast, easy, and effective when the lesion is raised above the skin surface. The shave biopsy is also valuable for diagnosing many cutaneous malignancies, including basal cell carcinomas (BCCs) and squamous cell carcinomas (SCCs). It is also an effective tool for removing benign lesions such as intradermal nevi and seborrheic keratoses. After a shave biopsy, hemostasis is easily obtained with aluminum chloride. The surface is allowed to heal naturally, and no sutures are needed. The excision site usually heals well with a good cosmetic result.

Indications

The following lesions are among those that are frequently diagnosed by shave biopsy:

• BCC (Figure 9-1)

• SCC (Figure 9-2)

• Keratoacanthoma (KA) (Figure 9-3)

• Dysplastic nevus (Figure 9-4).

FIGURE 9-1 Elevated pearly lesion in the nasolabial fold with telangiectasias. A shave biopsy is performed to rule out a BCC.

(Copyright Richard P. Usatine, MD.)

FIGURE 9-2 Shave biopsy of SCC on the lip.

(Copyright Richard P. Usatine, MD.)

FIGURE 9-3 A keratoacanthoma on face is appropriate for a shave biopsy.

(Copyright Richard P. Usatine, MD.)

FIGURE 9-4 Dysplastic nevus can be shaved with a deep shave for diagnosis and treatment.

(Copyright Richard P. Usatine, MD.)

Shave excision can also be used to remove the following benign lesions:

• Benign melanocytic nevus

• Seborrheic keratosis (Figure 9-5)

• Sebaceous hyperplasia

• Pyogenic granuloma (PG) (Figure 9-6)

• Skin tag with a broad base

• Single large wart

• Neurofibroma.

FIGURE 9-5 Shave excision of a verrucous-appearing seborrheic keratosis on the forehead.

(Copyright Richard P. Usatine, MD.)

FIGURE 9-6 Shave biopsy of PG on finger.

(Copyright Richard P. Usatine, MD.)

When a pigmented lesion appears to be benign and its removal is for cosmetic reasons, it is acceptable to use a shave excision. However, it is essential to send biopsies of all potentially suspicious lesions for review by a pathologist. A typical skin tag does not need to be sent to pathology.

Contraindications

There are no contraindications for shave biopsy based on location of the lesion. The use of a shave biopsy to diagnose a melanoma is controversial with a wide range of opinions. A superficial shave biopsy of a suspected melanoma runs the risk of losing important depth information used for staging and margin determination. However, if the melanoma is thin and the shave biopsy gets below the tumor, then nothing is lost. On the other hand, if a punch biopsy is performed of a large lesion and the punch misses the area with melanoma, this false-negative result can lead to missing the diagnosis of the melanoma. Although doing a complete full-thickness biopsy of a small suspected melanoma is optimal, this may be too deforming for a large superficial pigmented lesion on the face that might possibly be lentigo maligna melanoma (LMM) but appears more consistent with a solar lentigo (Figure 9-7). A broad scoop shave biopsy of LMM (Figure 9-8) may give a better tissue sample than one or more punch biopsies and will not cause the cosmetic deformities of a large full-thickness biopsy. It is also common practice to use a broad scoop shave to remove an atypical mole suspected of being a dysplastic nevus.

FIGURE 9-7 Solar lentigo.

(Copyright Richard P. Usatine, MD.)

FIGURE 9-8 Lentigo maligna melanoma.

(Copyright Richard P. Usatine, MD.)

In reality, the biopsy type is based on suspected diagnosis, size, location, patient preferences, and time considerations. It is better to diagnose a melanoma by shave biopsy than to lose a patient with melanoma to follow-up because you did not have the time to do an elliptical biopsy.

Advantages of A Shave Biopsy

The advantages of a shave biopsy can be broken down into two categories: those that are related to the clinician and those that are related to the patient. Advantages of a shave biopsy for the clinician include the following:

• Can be performed rapidly.

• Sutures are not needed.

• Procedure is relatively easy to learn.

• Multiple lesions can be easily excised at one time.

• An assistant is not required.

• Strict sterile procedure is not required.

The following advantages of a shave biopsy benefit the patient:

• There are no sutures that need to be removed.

• Wound care is usually simple.

• Restriction of activities is not needed during wound healing.

• The risks of infection and bleeding are reduced.

• It may give a better cosmetic result than a full-thickness excision.

• Even if a change in pigmentation occurs, it is easily covered by cosmetics.

A number of studies have shown the shave biopsy to produce a better cosmetic result than the punch biopsy and the fusiform diagnostic excision.¹^–³

Disadvantages of A Shave Biopsy

As with the advantages of the shave biopsy, the disadvantages can also be categorized into those for the clinician and those for the patient. Disadvantages for the clinician include the following:

• If the lesion turns out to be a melanoma, the shave may interfere with determining the depth of the lesion if the shave did not get below the tumor and the whole lesion was removed.

• Shave biopsies of flat lesions are more challenging than elevated lesions and a punch biopsy may be easier for an inexperienced clinician.

For the patient, the disadvantages of shave biopsy include the following:

• An indentation (divot) may remain.

• Hypopigmentation or hyperpigmentation may result.

• Regrowth may occur.

• A second surgery may be needed if the whole lesion needs excision.

• Scarring may occur over the whole biopsy site.

A superficial shave biopsy should heal with little to no indentation of the skin.⁴ Deep-shave biopsies are more likely to leave an indentation. Persistence rates of melanocytic lesions for shave biopsy range from approximately 13% to 28%.⁵ Persistence does not always translate into regrowth. If regrowth does occur, it is important to have access to the original pathology report to avoid overdiagnosing a benign regrowth as a melanoma (pseudomelanoma). Methods useful to differentiate pseudomelanoma from melanoma include accurate clinical records of prior biopsy sites along with evidence of scarring within the current biopsy.⁵

Equipment

The minimum equipment necessary for a shave biopsy is a sharp blade (razor blade or No. 15 scalpel), a 3-mL syringe and needle for local anesthesia, and cotton-tipped applicators (CTAs) and aluminum chloride for hemostasis. It is handy to have a forceps to hold the lesion during the shave procedure or to transfer the tissue into the biopsy container. (The end of a CTA can also be used to do this transfer in many cases.) A surgical marking pen can be useful and is best used before administering the anesthesia.

The Personna DermaBlade is an excellent razor blade for shave biopsies. The blue plastic handle makes it easy and safe to grip the sharp razor blade and control the blade for an accurate and precise shave excision. The cost of the disposable DermaBlade is about the same as a standard disposable No. 15 scalpel. Other options include the Personna or Wilkinson double-edge razor blade. The Personna (or Personna Plus with Teflon coating) double-edge blade is very sharp and can be broken in half for easy use (Figure 9-9). Although these do not come in sterile packaging, they can be safely used for shave biopsies without using the autoclave. At approximately 15 cents per cutting blade (30 cents per two-sided blade), these are the most cost-effective tool for shave biopsies. They can be broken in half within their paper container to avoid cutting your hand prior to use. It might take some more time to get used to the bare blade, but once you have mastered its use, you will find this type of low-cost blade to be sharp and effective.

FIGURE 9-9 Shave biopsy with a double-edge Personna blade that was snapped in half before use. The blade easily cuts through this pigmented BCC.

(Copyright Richard P. Usatine, MD.)

Miltex produces a BiopBlade flexible scalpel for shave biopsies. Its design is similar to that of the DermaBlade, using a single-edge razor blade with a plastic bendable handle. It is currently more expensive than the DermaBlade and has no advantages over the DermaBlade. The plastic handle can snap in half if the blade is bent incorrectly. The Personna single-edge razor blade is too rigid for shave biopsies. All of these blades (Figure 9-10) are available for purchase through Delasco (www.delasco.com) and some can be purchased through other suppliers.

FIGURE 9-10 Equipment used to perform a shave biopsy.

(Copyright Richard P. Usatine, MD.)

Shave Biopsy: Steps and Principles

Three critical steps in the shave biopsy include:

• Using 1% lidocaine with epinephrine for anesthesia and hemostasis.

• Stabilizing the lesion to allow for controlled removal of the biopsy.

• Dealing with any residual tissue after the initial shave.

Preoperative Measures

• After determining that the shave technique is the best method for the patient, obtain informed consent. (See Appendix A for an informed consent form titled Disclosure and Consent: Medical and Surgical Procedures.) By visual inspection and palpation, determine the likely depth of the lesion and plan the depth of your biopsy based on the probable diagnosis and your physical exam.

• Lightly prep the area with alcohol or another antiseptic. There is no evidence that this preparation decreases the already extremely low infection rate, but it is easy to do.

• If it appears that the lesion will have fewer visible margins after the anesthesia, it helps to mark the area to be shaved with a surgical marker. It need not be a sterile marker. Consider marking the margins of nonpigmented relatively flat lesions that may only be actinic keratoses or sebaceous hyperplasia (but are somewhat suspicious for early skin cancer), because after injection the margins of these lesions may not be visible (Figure 9-11).

• Inject local anesthesia. Use a 30-gauge needle with approximately 2 to 3 mL of 1% lidocaine and epinephrine (buffer the lidocaine for less pain; see Chapter 3, Anesthesia). Start with the needle under the lesion (greater depth is less painful) and then give the last amount of anesthesia closer to the skin surface. If the lesion is flat, consider raising the lesion some with the anesthesia (Figure 9-12A).