When to Refer/Mohs Surgery

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37 When to Refer/Mohs Surgery

John L. Pfenninger, MD, and Richard P. Usatine, MD

The primary care clinician handles a multitude of problems and each person has his or her own level of comfort and expertise. There are no hard-and-fast guidelines to determine when a consultation/referral should be obtained. Some clinicians will feel very comfortable performing extensive flaps, whereas others will be anxious about doing a fairly straightforward skin biopsy. This chapter provides some general guidelines to help gauge when, and if, the expertise of another clinician is needed.

When to Refer

In general, a referral means that the patient is being turned over to another physician for care. A consult asks for direction, but the patient remains under the care of the consulting physician. In practice, these two terms are often used interchangeably. The term verbal consult is often used to relay the fact that the case was discussed with someone else for input and direction as to proper care but not referred formally. Although discouraged on a legal basis, it is commonly done and for simple questions such as “What should the margins of the excision be?” it functionally works well.

Medical-legal considerations are important. Hospitals may limit privileges and require that a referral be made for performing certain procedures in hospital-owned facilities. In such cases, it may not be a matter of expertise, but rather of legal restriction as to what may be done.

HMOs and insurance companies may also limit the ability of a clinician to employ the full use of his or her skills. Some restrict payment to certain specialties only. It is not a matter of competence (despite the insurers’ claims), but rather a matter of rules, regulations, and “protecting turf.”

It is important for clinicians to always provide complete disclosure to patients about their background and training. Patients must not be misled into thinking that the physician assistant, nurse practitioner, family physician, or internist is a dermatologist or plastic surgeon. The simplest procedure for professionals may appear to be very complex to the patient and can be a fearful ordeal. It is always appropriate to mention that a dermatologist, plastic surgeon, or referral to some other center is readily available should the patient so desire. A statement such as “This is a common procedure that has few complications. I perform it frequently and I would be happy to do it for you. However, if you’d like to see someone else, I understand and can easily arrange a referral” goes a long way toward putting the patient at ease. Do not forget the family members in the equation. Some may be extremely concerned about a scar, even though it involves an elderly parent. These issues need to be discussed and dealt with prior to performing any procedure. If the patient or the family appears to be hesitant, it is prudent to make a referral.

No clinician will ever feel totally comfortable in every situation that he or she will encounter. Sometimes, too, a straightforward diagnosis and planned treatment becomes more complicated than expected. It is important to have lines of communication open with other specialists so that when these “complications” do arise, the clinician has support. Whether this consultant is a plastic surgeon, dermatologist, general surgeon, or another colleague who performs the same procedure, it is important to have the backup. Immediate complications will most likely involve bleeding or the inability to close a large, gaping wound; wound dehiscence; or nonhealing of a treated site. Rarely, a nerve may be transected or the repair may leave the surrounding structures distorted. Long-term complications include scarring, missing a diagnosis, or recurrence.

Clinicians should not be hesitant to perform a skin biopsy. Multiple methods are available (see Chapters 8 through 11). Complications are so rare, and the benefits are so great, that all clinicians, especially those in primary care, should consider mastering this skill. If one wants to limit procedural acumen solely to skin biopsies, then referral would be necessary for many findings. However, the average primary care clinician should be able to evaluate and treat 95% of all dermatologic conditions that come into the office using the techniques described in this text. Cryotherapy, electrosurgery, injection techniques, laceration repair, and simple incisions/excisions will be adequate to treat the majority of conditions. When the excisions become larger and more complicated, it is then that many patients may need to be referred.

Keeping in mind all of the considerations noted above, the clinician will individually define when a referral is indicated. As expertise increases with training and experience, fewer consultations and referrals will be needed. General guidelines for when to consult and when to refer include the following:

1. Lack of experience with the method needed for diagnosis and/or treatment.

2. Significant cosmetic concerns with the skills for removal being beyond the practitioner’s comfort level.

3. Large lesions, whether benign or malignant. These often need to be referred to a specialist. “Large” is relative and depends on the practitioner’s expertise and the nature of the lesion (benign or malignant, location, new or recurrent, etc.).

4. Request by the patient or the family for a referral.

5. A poor or questionable patient–doctor relationship.

6. An uncooperative patient.

7. Medical-legal or insurance requirements/regulations.

8. Advanced and/or complicated disease. In general, the major considerations for aggressiveness of a tumor are histologic type, size, and location of the lesion.

All factors should be considered when deciding whether or not to make a referral. The skin cancers that cause the most concern for all of us can be categorized as follows by histologic type (from least to most aggressive):

Basal Cell Carcinoma (BCC)

• Morpheaform (aggressive, sclerotic)

• Perineural invasion.

Squamous Cell Carcinoma (SCC)

• In situ (depending on size and location, generally does not need aggressive treatment)

• Invasive (more aggressive on mucus membranes and non-sun-exposed areas)

• Perineural invasion.

Melanoma

• In situ

• Superficial

• <1-mm invasion with no ulceration or neural involvement

• >1-mm invasion or with ulceration or neural involvement.

Other, More Rare and Potentially Aggressive Cancers

• These include dermatofibrosarcoma protuberans, cutaneous T-cell lymphoma, Merkel cell carcinoma. See the end of Chapter 34 for photographs and further information on these skin cancers.

The following are examples of when most primary care clinicians might consider a referral ¹^–⁶:

1. A melanoma with invasion 1 mm or deeper or if there is neural involvement or ulceration: Some would want to refer all melanomas. However, those less than 1 mm in depth are generally treated with simple excision using 1-cm free margins. Once the melanoma has invaded 1 mm or more, then the workup becomes much more extensive, often including a sentinel node biopsy. Surgical oncologists and melanoma clinics that deal with melanomas on a routine basis are more likely to provide the patient with more options for an improved outcome. Most dermatologists refer melanomas with Breslow depth over 1.0 mm because they do not do sentinel node biopsies.

2. Rare, unusual tumors or metastatic disease: for example, dermatofibrosarcoma protuberans, Merkel cell tumors, and any metastatic cancer to or from the skin (Figure 37-1).

3. Recurrent skin cancers, such as SCC, which can metastasize: Even BCCs, which generally do not metastasize, can recur and require large margins for resection (Figure 37-2). Mohs micrographic surgery or radiation may be indicated in such cases.

4. Large nonmelanoma skin cancers (NMSC) >1 cm in length or diameter, unless the clinician is capable of performing large excisions: Many basal cell carcinomas <1 cm in size can be treated with ablation/destruction techniques, such as electrodesiccation and curettage or cryotherapy. Small SCC < 1 cm can be excised with 5-mm margins. Although some physicians refer all skin cancers for Mohs surgery, this is not a true cost-effective approach. A higher cure rate is sometimes cited to justify Mohs, but with lesions <1 cm (BCCs and SCCs), the benefit is very small, and the scarring may be less with ablative techniques.

5. High-risk anatomic areas: temporal (temporal branch of facial nerve), lateral neck (spinal accessory nerve), nasolabial groove with ablation (higher recurrence of skin cancers when size is over 0.6 cm), lacrimal duct area (scarring), excisions near eyelids (ectropion or entropion).

6. High-risk lesions: These include SCC on the lips, temple, and ears as these have a 10% rate of metastasis. SCC also requires more aggressive treatment if it is >2 cm, occurs in a scar, or there is evidence of perineural invasion.

7. High-risk patients: These include those with diabetes, immune suppression, obesity, peripheral vascular disease, stasis dermatitis/pedal edema with lower extremity lesions, alcoholics, HIV/AIDS, malnutrition.

8. Areas where even normal scarring may be especially critical: For example, the eyelid margins and face, especially in the young/female patient; the vermilion border.

9. Patients who easily form hypertrophic- or keloid-scars.

10. Non-adherent patients or those with unrealistic expectations.

FIGURE 37-1 These scattered black nodules are caused by metastatic melanoma to the skin. The patient was referred directly to medical oncology.

(Copyright Richard P. Usatine, MD.)

FIGURE 37-2 Two recurrent BCCs are seen along the scar from a previous large flap that was used after a large BCC was removed from the neck. The patient was referred for Mohs surgery.

(Copyright Richard P. Usatine, MD.)

Mohs Surgery

Mohs surgery is a technique in which careful mapping of a lesion (usually an NMSC) is performed using marking dye at the time of the removal.^7,⁸ The lesion is excised and immediately processed histologically. Areas of residual tumor are identified under the microscope by the Mohs surgeon and further excision completed in the specific areas needed. It is generally performed in an office under local anesthesia. The advantage is that the entire tumor can be removed with cure rates as high as 99%. The disadvantages are the time and costs to perform the procedure. Most reviews have found it to be cost effective for high-risk cancers. Potential indications for Mohs are noted in Box 37-1. Medicare will cover reimbursement for Mohs micrographic surgery for the diagnoses and indications listed in Box 37-2.

Box 37-1

Indications for Mohs Micrographic Surgery in Patients with High-Risk Skin Cancers

• High-risk anatomic location (eyelids, nose, ears, lips, genitalia, fingers)

• Large tumors (20 mm or more in diameter) on the torso and extremities

• Recurrent tumors after previous excision or destruction

• Tumors occurring in previous sites of radiation therapy

• Tumors with aggressive histologic patterns (small strand, infiltrative, or morphea-like growth in BCCs; perineural invasion; or poorly differentiated histology or deep invasion in squamous cell carcinomas)

• Tumors in immunosuppressed patients

• Tumors with involved borders or vague clinical margins, or incompletely excised tumors (positive histologic margins after resection).

Source: Adapted from National Comprehensive Cancer Network. Clinical Practice Guidelines in Oncology: Basal Cell and Squamous Cell Skin Cancers. Version 1.2010. Accessed online April 13, 2010, at http://www.nccn.org/professionals/physician_gls/PDF/nmsc.pdf.

Box 37-2 Medicare Covers Reimbursement for Mohs Surgery for these Diagnoses

1. Basal cell, squamous cell, or basalosquamous cell carcinomas in anatomic locations where they are prone to recur:

• Central facial areas, periauricular, nose, and temple areas of the face (the so-called “mask area” of the face)

• Lips, cutaneous and vermilion

• Eyelids and periorbital areas

• Auricular helix and canal

• Chin and mandible.

2. Other skin lesions:

• Angiosarcoma of the skin

• Keratoacanthoma, recurrent

• Dermatofibrosarcoma protuberans

• Malignant fibrous histiocytoma

• Sebaceous gland carcinoma

• Microcystic adnexal carcinoma

• Extramammary Paget’s disease

• Bowenoid papulosis

• Merkel cell carcinoma

• Bowen’s disease (squamous cell carcinoma in situ)

• Adenoid type of squamous cell carcinoma

• Rapid growth in a squamous cell carcinoma

• Long-standing duration of a squamous cell carcinoma

• Verrucous carcinoma

• Atypical fibroxanthoma

• Leiomyosarcoma or other spindle cell neoplasms of the skin

• Adenocystic carcinoma of the skin

• Erythroplasia of Queyrat

• Oral and central facial, paranasal sinus neoplasm

• Apocrine carcinoma of the skin

• Malignant melanoma (facial, auricular, genital and digital) when anatomic or technical difficulties do not allow conventional excision with appropriate margins.

Patient Selection

Examples of patients that were referred for Mohs surgery including those with the following lesions:

• Pigmented BCC on the nose, newly diagnosed (Figure 37-3)

• BCC on the upper lip close to the vermilion border (Figure 37-4)

• Infiltrating BCC on the cheek (Figure 37-5)

• Recurrent squamous cell carcinoma on the cheek (Figure 37-6)

• BCC on the ear, newly diagnosed (Figure 37-7).

FIGURE 37-3 Resecting this pigmented BCC on the nose can easily result in a nasal deformity. The patient was referred for Mohs surgery to get the highest cure rates and the best cosmetic result.

(Copyright Richard P. Usatine, MD.)

FIGURE 37-4 The BCC on the upper lip approaches the vermilion border. Unless you are experienced in facial flaps, this is a good patient to refer for Mohs surgery and a flap repair.

(Copyright Richard P. Usatine, MD.)

FIGURE 37-5 (A) This patient was referred for Mohs surgery to treat his sclerosing BCC. (B) The BCC had extensively infiltrated his cheek and required three stages to get clear margins. (C) A repair was able to close the defect to heal by primary intention.

(Courtesy of Ryan O’Quinn, MD.)

FIGURE 37-6 Squamous cell carcinoma was found to be recurrent along the excision scar on the face. When Mohs surgery was performed, the SCC was found to have infiltrated deeply and widely resulting in the defect in this image.

(Copyright Richard P. Usatine, MD.)

FIGURE 37-7 A new BCC was diagnosed on the pinna and the patient was referred for Mohs surgery. See next figures.

(Copyright Richard P. Usatine, MD.)

Performing Mohs Surgery

1. Local anesthetic with lidocaine and epinephrine is administered.

2. The tumor is debulked with a scalpel and discarded.

3. A saucer-shaped section of the remaining tumor including lateral and deep margins is cut out (Figure 37-8).

4. The piece is processed, including inking and cut into four quarters if the pieces are too large for a single slide.

5. The laboratory technician freezes and stains the segments (Figure 37-9).

6. The Mohs surgeon reads the histology looking at all margins.

7. If there are any positive margins, a second stage is performed.

8. The process continues until there are completely clear margins.

9. The defect is repaired using Burow’s triangles to create a simple ellipse or a more elaborate flap.

FIGURE 37-8 After debulking the tumor, the Mohs surgeon carefully removes a segment of the skin with margins laterally and deep.

(Copyright Richard P. Usatine, MD.)

FIGURE 37-9 Mohs slides in the tray ready to be viewed under the microscope.

(Copyright Richard P. Usatine, MD.)

Standard pathology for an ellipse involves bread loaf examination of the tissue (Figure 37-10). Mohs surgery is done with a more complete examination of the margin (Figure 37-11).

FIGURE 37-10 A standard elliptical excision of tumor followed by vertical sectioning “bread loafing.” Here, all margins appear to be clear based on the sections evaluated at the top of the figure. However, the positive margin between sections B and C was not evaluated. Hence, the higher risk of recurrence with an ellipse rather than Mohs surgery.

(From Vidimos A, Ammirati C, Poblete-Lopez C. Dermatologic Surgery. London: Saunders; 2008.)

FIGURE 37-11 In Mohs surgery, the tumor is removed in a saucer-shaped section and divided into pieces for processing. Evaluation of all excised margins reveals skin cancer present at one of the dermal edges of excision. This area is subsequently excised to remove the rest of the tumor.

(From Vidimos A, Ammirati C, Poblete-Lopez C. Dermatologic Surgery. London: Saunders; 2008.)

One way to consider who to refer is to look at Figure 37-12 of the H-zone and the levels of recurrence risk. The H-zone resembles the letter “H” and is the highest risk area.