164 squamous cell carcinoma

712 CHAPTER 164PART 13

DERMATOLOGY

164 SQUAMOUS CELLCARCINOMA

Richard P. Usatine, MD

PATIENT STORY

A 66-year-old farmer presents with new growths on his scalp(Figure 164-1).The patient admits to lots of sun exposure and hasalready had one squamous cell carcinoma (SCC) excised from thescalp 5 years ago. On close inspection there are four particularly sus-picious areas. Figure 164-1 shows four sites that have already beenbiopsied with shave biopsies.The final p thology demonstrated thatthree out of four sites were positive for SCC. Figure 164-2 demon-strates the shave biopsy technique using a Dermablade.The patientwas referred for Mohs surgery to fully excise the three positive areas.

EPIDEMIOLOGY

• SCC is the second most common skin cancer seen accounting for16% of skin cancers.

• The most important risk factors for SCC of the skin are sun expo-sure and skin type.

• Less common predisposing factors include chemical exposures,HPV, and burns.

• Incidence of SCC increases with age, related to cumulative sun ex-posure.

• Metastasis from SCC occurs in 2% to 6% of cases.1

• SCCs that metastasize most often start on the mucous membranesor lips or sites of chronic inflamm tory skin conditions.

• In the United States, approximately 2,500 people die from SCCevery year.1

PATHOPHYSIOLOGY

SCC is a malignant tumor of keratinocytes. Most SCCs arise from ac-tinic keratoses. SCCs usually spread by local extension but are capableof regional lymph node metastasis and distant metastasis. HPV-relatedlesions may be found on the penis, labia, or in the periungual region.1

DIAGNOSIS

• The only sure method of making the diagnosis is a biopsy. Biopsysuspicious lesions (thickened, indurated, ulcerated, or crusting) inareas with signs of sun exposure. Even suspicious lesions in non-sun-exposed areas need biopsy and can be SCCs.

FIGURE 164-1 Three squamous cell carcinomas (SCCs) on the scalp ofa farmer. The SCCs were found at the sites labeled SCC 1, SCC 2, andSCC B. (Courtesy of Richard P. Usatine, MD.)

FIGURE 164-2 Shave biopsy of a new SCC on the head of the patientin Figure 164-1 one year later. (Courtesy of Richard P. Usatine, MD.)

MHBD125-164[712-719].qxd 8/15/08 7:05 PM Page 712

713

CLINICAL FEATURES

SCC often present as areas of persistent ulceration, crusting, hyperk-eratosis, and erythema, especially on skin showing evidence of sundamage.

Less common types of SCC:

• Marjolin’s ulcer—SCC of the extremities found in chronic skin ul-cers or burn scars (Figure 164-3).

• Erythroplasia of Queyrat—SCC in situ on the penis or vulvarelated to HPV infection (Figure 164-4).This can progress to fullinvasive SCC of the penis (Figure 164-5).

TYPICAL DISTRIBUTION

SCC is found in all sun exposed areas and on mucus membranes.Themost common sites are:

• Face (Figures 164-6 and 164-7).

• Lower lip (Figures 164-8 and 164-9).

• Ears (Figure 164-10).

• Scalp (Figures 164-1 and 164-11).

• Extremities—arm—(Figures 164-12 and 164-13).

• Bands (Figure 164-14).

• Fingers (Figure 164-15).

• Mucus membranes (see Chapter 42, Oral Cancer).

BIOPSY

• Deep shave biopsy is adequate to make the diagnosis of most SCCs.

• Punch biopsy is an alternative for lesions that are pigmented orappear to be deeper.

FACTORS AFFECTING METASTATIC POTENTIAL OF CUTANEOUS SCC2

The following factors are taken from the “Multiprofessional guidelinesfor the management of the patient with primary cutaneous squamouscell carcinoma.”2

• Site.

Tumor location influences p ognosis: sites are listed in order ofincreasing metastatic potential.2

1. SCC arising at sun-exposed sites excluding lip and ear.

2. SCC of the lip (Figures 164-8 and 164-9).

3. SCC of the ear (Figure 164-10).

4. Tumors arising in non-sun-exposed sites (e.g., perineum, sacrum,sole of foot) (Figures 164-4 and 164-5).

5. SCC arising in areas of radiation or thermal injury, chronic drain-ing sinuses, chronic ulcers, chronic inflamm tion, or Bowen’s dis-ease, such as the SCC arising in a burn site (Figure 164-3).

• Size: diameter.

FIGURE 164-4 Erythroplasia of Queyrat (SCC in situ) under the fore-skin of an uncircumcised man. This is related to HPV infection as is cer-vical cancer. (Courtesy of John Pfenninger, MD.)

FIGURE 164-3 Marjolin’s ulcer (SCC) arising in a large burn thatoccurred years before on the legs of a woman living in India. (Courtesyof Colby McLaren, MD.)

SQUAMOUS CELL CARCINOMAPART 13

DERMATOLOGY

MHBD125-164[712-719].qxd 8/15/08 7:05 PM Page 713


DERMATOLOGY

Tumors larger than 2 cm in diameter are twice as likely to recurlocally (15.2% vs 7.4%), and three times as likely to metastasize(30.3% vs 9.1%) as smaller tumors.

• Size: depth.

Tumors greater than 4 mm in depth (excluding surface layers of ker-atin) or extending down to the subcutaneous tissue (Clark level V) aremore likely to recur and metastasize (metastatic rate 45.7%)compared with thinner tumors. Recurrence and metastases are lesslikely in tumors confined to the upper half of the de mis and less than4 mm in depth (metastatic rate 6.7%).

• Histologic differentiation.

Poorly differentiated tumors have a poorer prognosis, with more thandouble the local recurrence rate and triple the metastatic rate of bet-ter differentiated SCC.Tumors with perineural involvement are morelikely to recur and to metastasize.

• Host immunosuppression.

Tumors arising in patients who are immunosuppressed have a poorerprognosis. Host cellular immune response may be important both indetermining the local invasiveness of SCC and the host’s response tometastases. Figures 164-16 to 164-18 are SCCs in patients that areHIV positive.

• Previous treatment and treatment modality.

The risk of local recurrence depends upon the treatment modality.Locally recurrent disease itself is a risk factor for metastatic disease.Local recurrence rates are considerably less with Mohs’ micrographicsurgery than with any other treatment modality.

DIFFERENTIAL DIAGNOSIS

• Actinic keratoses are precancers on sun-exposed areas, which canprogress to SCC (see Chapter 159,Actinic Keratosis and Bowen’sDisease).

• Bowen’s disease is SCC in situ before it invades the basement mem-brane (see Chapter 159,Actinic Keratosis and Bowen’s Disease).

• Keratoacanthoma is a lesion that can grow rapidly and often has acentral keratinized crater. Figure 164-18 resembles a keratoacan-thoma but is actually a SCC. Keratoacanthomas can also be consid-ered to be a type of SCC (see Chapter 160, Keratoacanthomas).

• Basal Cell Carcinoma cannot always be distinguished from SCC byclinical appearance alone. Both Figures 164-16 and 164-17 couldbe BCCs by appearance but were proven to be SCC by biopsy (seeChapter 163, Basal Cell Carcinoma).

• Market cell carcinoma (neuroendocrine carcinoma of the skin) is arare aggressive malignancy. It is most commonly seen on the face ofwhite elderly persons. It can resemble a SCC and the diagnosis ismade on biopsy (Figure 164-19).

• Nummular eczema can usually be distinguished by the multiplecoin-like shapes, transient nature, and pruritus (Chapter 139,Atopic Dermatitis).

FIGURE 164-6 SCC on the tip of the nose of an older woman. (Cour-tesy of the Skin Cancer Foundation.)

FIGURE 164-5 SCC of the penis. (Courtesy of Jeff Meffert, MD.)

MHBD125-164[712-719].qxd 8/15/08 7:05 PM Page 714

715

MANAGEMENT

The following recommendations are derived from the “Multiprofes-sional guidelines for the management of the patient with primary cu-taneous squamous cell carcinoma.”2 See Table 164-1 for a summaryof treatment options.

Surgical resection for definiti e treatment should include marginsas given below:

4-mm margin—should be adequate for well-defined low-risk tu-mors less than 2 cm in diameter, such margins are expected toremove the primary tumor mass completely in 95% of cases.2 SOR�

6-mm margin—recommended for larger tumors, high-risktumors, tumors extending into the subcutaneous tissue and those inhigh-risk locations (ear, lip, scalp, eyelids, nose).2

MOHS’ MICROGRAPHIC SURGERY

Allows precise definition and excision of p imary tumor growing incontinuity, thereby reducing errors in primary treatment that mayarise owing to clinically invisible tumor extension.There is good evi-dence that the incidence of local recurrent and metastatic disease arelow after Mohs’ micrographic surgery and it should, therefore, beconsidered in the surgical treatment of high-risk SCC, particularly atdifficult sites whe e wide surgical margins may be technically difficulto achieve without functional impairment.2 SOR�

CURETTAGE AND ELECTRODESICCATION

Excellent cure rates have been reported in several series, and experi-ence suggests that small (�1 cm) well-differentiated primary slow-growing tumors arising on sun-exposed sites can be removed by ex-perienced physicians with curettage.2

The experienced clinician undertaking curettage can detect tumortissue by its soft consistency and this may be of benefit in identifyininvisible tumor extension and ensuring adequate treatment.Electrodesiccation is applied to the curetted wound and thecurettage-cautery cycle then repeated twice. SOR�

CRYOSURGERY

Good short-term cure rates have been reported for small, histologi-cally confi med SCC treated by cryosurgery in experienced hands.Prior biopsy is necessary to establish the diagnosis histologically.There is great variability in the use of liquid nitrogen for cryotherapy.Start by drawing a 4- to 6-mm margin around the SCC and then use atotal freeze time of 60 seconds.This can be divided up into two 30-second freezes with a thaw in between. Some patients might preferlocal anesthetic if the freezing is too painful. SOR�

Cryosurgery and curettage and electrodesiccation are notappropriate for locally recurrent disease.

RADIOTHERAPY

Radiation therapy alone offers short- and long-term cure rates forSCC that are comparable with other treatments. It is recommendedfor lesions arising on the lip, nasal vestibule (and sometimes the out-side of the nose), and ear. Certain very advanced tumors, where sur-gical morbidity would be unacceptably high, may also be best treatedby radiotherapy. SOR�

FIGURE 164-8 SCC on the lower lip. (Courtesy of the Skin CancerFoundation.)

FIGURE 164-7 Large SCC on the cheek of an older man. (Courtesy ofthe Skin Cancer Foundation.)


DERMATOLOGY

MHBD125-164[712-719].qxd 8/15/08 7:05 PM Page 715


DERMATOLOGY

ELECTIVE PROPHYLACTIC LYMPH NODE DISSECTION

Elective prophylactic lymph node dissection has been proposed forSCC on the lip greater than 6 mm in depth and cutaneous SCCgreater than 8 mm in depth, but evidence for this is weak. SOR�

FOLLOW-UP

Patients should be seen at least yearly for skin examinations after thediagnosis and treatment of a SCC.The 3-year risk of recurrence of anew SCC after having a single SCC is 18%.3

PATIENT EDUCATION

Includes use of a hat and sunscreen on a regular basis with frequentfollow-up for early recognition of new skin cancers.

PATIENT AND PROVIDER RESOURCE

Skin Cancer Foundation has an excellent web site with photos andpatient information http://www.skincancer.org/squamous/index.php.

FIGURE 164-10 Large SCC on the pinna that has features suggestiveof a BCC or keratoacanthoma. (Courtesy of the Skin CancerFoundation.)

FIGURE 164-9 SCC showing ulceration on the lower lip. (Courtesy ofRichard P. Usatine, MD)

MHBD125-164[712-719].qxd 8/15/08 7:05 PM Page 716

717

FIGURE 164-12 Large pedunculated SCC on the shoulder of a 92-year-old woman. (Courtesy of Richard P. Usatine, MD.)

FIGURE 164-13 Large ulcerating SCC on arm. (Courtesy of Richard P.Usatine, MD.)

FIGURE 164-14 SCC on the dorsum of the hand. (Courtesy of the SkinCancer Foundation.)

FIGURE 164-11 SCC on the shaven scalp of a 35-year-old man, whichwas formerly mistaken for a wart. (Courtesy of Richard P. Usatine, MD.)


DERMATOLOGY

MHBD125-164[712-719].qxd 8/15/08 7:05 PM Page 717


DERMATOLOGY

FIGURE 164-15 SCC on the finger. It took two biopsies to establishthe correct diagnosis. (Courtesy of Richard P. Usatine, MD.)

FIGURE 164-16 Large SCC on the arm of an HIV positive 51-year-oldman. It grew to this size in one year and took two biopsies to get a de-finitive diagnosis. Differential diagnosis includes mycosis fungoides.(Courtesy of Richard P. Usatine, MD.)

FIGURE 164-18 SCC on the shoulder of an HIV positive man. Notethat the pearly borders and telangiectasias resemble a BCC and thecentral crater suggests that this could be a keratoacanthoma.(Courtesy of Richard P. Usatine, MD.)

FIGURE 164-19 Merkel cell carcinoma on the lower lip of an elderlywoman. This is an aggressive cancer with a high mortality rate. (Cour-tesy of Jeff Meffert, MD.)

FIGURE 164-17 SCC invading the internal nasal structures in an HIV-positive man who was afraid of having a biopsy done earlier. Patient re-ferred to ENT. (Courtesy of Richard P. Usatine, MD.)

MHBD125-164[712-719].qxd 8/15/08 7:05 PM 18

719

REFERENCES

1. Goldman, G. Squamous Cell Carcinoma. www.emedicine.com/DERM/topic401.htm. 2007.Accessed November 7, 2007.

2. Motley R, Kersey P, Lawrence C. Multiprofessional guidelines forthe management of the patient with primary cutaneous squamouscell carcinoma. Br J Plast Surg. 2003;56:85–91.

3. Marcil I, Stern RS. Risk of developing a subsequent nonmelanomaskin cancer in patients with a history of nonmelanoma skin cancer:A critical review of the literature and meta-analysis. Arch Dermatol.2000;136:1524–1530.

TABLE 164-1 Summary of Treatment Options for Primary Cutaneous Squamous Cell Carcinoma2

Treatment Indications Contraindications Notes

Surgical excision All resectable tumors Where surgical morbidity is Generally treatment of likely to be unreasonably high choice for SCC

High-risk tumors need wide margins or histologicmargin control

Mohs’ micrographic High-risk tumors, recurrent Where surgical morbidity is Treatment of choice for surgery/excision with tumors likely to be unreasonably high high-risk tumorshistologic control

Radiotherapy Nonresectable tumors Where margins are ill-defined

Curettage and cautery Small, well-defined, low-risk High-risk tumors Curettage may be helpful tumors prior to surgical excision

Cryotherapy Small, well-defined, low-risk High-risk tumors, recurrent Only suitable for tumors tumors experienced practitioners

Reprinted from Motley R, Kersey P, Lawrence C. Multiprofessional guidelines for the management of the patient with primarycutaneous squamous cell carcinoma. Br J Plast Surg. 2003;56:85–91.


DERMATOLOGY

MHBD125-164[712-719].qxd 8/15/08 7:05 PM Page 719

164 squamous cell carcinoma

Documents