Chapter 170. Basal Cell Carcinoma

A 52-year-old woman presented to the office with a “mole” that had been increasing in size over the last year (Figure 170-1). This “mole” had been on her face for at least 5 years. The differential diagnosis of this lesion was a nodular basal cell carcinoma (BCC) versus an intradermal nevus. A shave biopsy confirmed it was a nodular BCC and the lesion was excised with an elliptical excision.

Basal cell carcinoma is the most common cancer in humans. Usually found on the head and neck, it is generally slow growing and almost never kills or metastasizes when treated in a timely fashion.  However, the treatment necessary to eliminate it is often surgical and may cause scarring and changes in appearance and/or function.

• BCC is the most common skin cancer but the exact incidence is not known.1
• Incidence of these cancers increases with age, related to cumulative sun exposure.
• Nodular BCCs—Most common type (70%) (Figures 170-1, 170-2, 170-3, and 170-4).
• Superficial BCCs—Next most common type (Figures 170-5 and 170-6).
• Sclerosing (or morpheaform) BCCs—The least common type (Figures 170-7 and 170-8).

Other clinical variants including pigmented, polypoid, giant, keloidal, linear, and fibroepithelioma of Pinkus have been recognized, but are less common to very rare.2

• BCCs spread locally and very rarely metastasize.
• Basal cell nevus syndrome, also known as Gorlin syndrome, is a rare autosomal dominant condition in which affected individuals have multiple BCCs that may clinically mimic nevi (Figure 170-9).

• Advanced age.
• Cumulative sun exposure.
• Radiation exposure.
• Latitude.
• Immunosuppression.
• Genetic predisposition.
• Family history.
• Skin type.3

Clinical Features

Common clinical features of the three most common morphologic types are listed below.

Nodular BCC

• Raised pearly white, smooth translucent surface with telangiectasias.
• Smooth surface with loss of the normal pore pattern (Figures 170-1, 170-2, 170-3, and 170-4).
• May be moderately to deeply pigmented (Figures 170-10, 170-11, and 170-12).
• May ulcerate (Figures 170-13, 170-14, 170-15, and 170-16) and can leave a bloody crust.

Superficial BCC

• Red or pink patches to plaques often with mild scale and a thready border (slightly raised and pearly) (Figure 170-5).
• Found more commonly on the trunk and upper extremities than the face.

Sclerosing (morpheaform)

• Ivory or colorless, flat or atrophic, indurated, may resemble scars, are easily overlooked (Figures 170-7 and 170-8).
• Called morpheaform because of their resemblance to localized scleroderma (morphea).
• The border is not well demarcated and the tumor can spread far beyond what is clinically visible (Figure 170-17).
• These BCCs are the most dangerous and have the worst prognosis.

Typical Distribution

Ninety percent appear on face, ears, and head, with some found on the trunk and upper extremities (especially the superficial type).1

Recently lesions on the ears have been associated with a more aggressive behavior (Figure 170-18).4

Dermoscopy

Dermoscopic characteristics of BCCs (Figures 170-19 and 170-20) include:

• Large blue-gray ovoid nests.
• Multiple blue-gray globules.
• Leaf-like areas, also called clods, that look like maple leaves.
• Spoke-wheel areas.
• Arborizing “tree-like” telangiectasia.
• Ulceration.
• Shiny white areas/stellate streaks (see Appendix C: Dermoscopy for further information).

Biopsy

• A shave biopsy is adequate to diagnose a nodular BCC or a thick superficial BCC.
• A scoop shave or punch biopsy is preferred for a sclerosing BCC or a very flat superficial BCC.
• In many instances, excision at the time of definitive treatment reveals a different morphologic type in deeper tissue.5

Nodular BCC

• Intradermal (dermal) nevi may look very similar to nodular BCCs with telangiectasias and smooth pearly borders (Figure 170-21). A history of stable size and lack of ulceration may be helpful in distinguishing them from a nodular BCC. A simple shave biopsy is diagnostic and produces a good cosmetic result. Excisional biopsy is usually unnecessary and can be deforming. It is remarkable how similar Figure 170-21 appears to Figure 170-1 (both biopsies proven to be as labeled) (see Chapter 162, Benign Nevi).
• Sebaceous hyperplasia is a benign adnexal tumor common on the face in older adults and usually occurs with more than one lesion present (Figure 170-22). This benign overgrowth of the sebaceous glands produces small waxy yellow to pink papules with telangiectasias. Dermoscopy may show vessels that radiate out from the center like spokes on a wheel (see Chapter 159, Sebaceous Hyperplasia).
• Fibrous papule of the face is a benign condition with small papules that can be firm and pearly.
• Trichoepithelioma/trichoblastoma/trichilemmoma are benign tumors on the face that can appear around the nose. They may be pearly but usually do not have telangiectasias. These are best diagnosed with a shave biopsy, but trichoepitheliomas can even mimic a BCC on histology.
• Keratoacanthoma is a type of squamous cell carcinoma that is raised, nodular, and may be pearly with telangiectasias. A central keratin-filled crater may help to distinguish this from a BCC (see Chapter 167, Keratoacanthoma).

Superficial BCC

• Actinic keratoses are precancers that are flat, pink, and scaly. They lack the pearly and thready border of the superficial BCC (see Chapter 166, Actinic Keratosis and Bowen Disease).
• Bowen disease is a squamous cell carcinoma in situ that appears like a larger thicker actinic keratosis with more distinct well-demarcated borders. It also lacks the pearly and thready border of the superficial BCC (see Chapter 166, Actinic Keratosis and Bowen Disease).
• Nummular eczema can usually be distinguished by its multiple coin-like shapes, transient nature, and rapid response to topical steroids. These lesions are extremely pruritic and most patients will have other signs and symptoms of atopic disease (see Chapter 145, Atopic Dermatitis).
• Discoid lupus erythematosus is a cutaneous manifestation of autoimmune disease and often presents with skin color change, scaling, and hair follicle destruction. These have characteristic predilection for the ears, scalp, and face, but may be found on the trunk and extremities.
• Benign lichenoid keratosis is a variably scaly flat or slightly raised benign reactive neoplasm on sun-damaged skin. It is often on the trunk or extremities and can have blue-gray globules on dermoscopy and some pearly color.

Sclerosing (morpheaform) BCC

• Scars may look like a sclerosing BCC. Ask about previous surgeries or trauma to the area. If the so-called scar is flat, shiny, and enlarging, a biopsy still may be needed to rule out a sclerosing BCC.

• Mohs micrographic surgery (3 studies, n = 2660) is the gold standard but is not needed for all BCCs. Recurrence rate is 0.8% to 1.1% (Figure 170-17B). Mohs micrographic surgery (pioneered by Dr. Frederick Mohs) entails surgical removal of tumors with immediate histologic processing in sequential horizontal layers preserving a continuous peripheral margin that is mapped to the clinical lesion. Concentric surgical margins are taken until all margins are clear (Figure 170-17). This is the treatment of choice for BCCs with poorly defined clinical margins or in areas of significant cosmetic or functional importance such as the face.6 SOR A
• Surgical excision (3 studies, n = 1303): Recurrence rate was 2% to 8%. Mean cumulative 5-year rate1 (all 3 studies) was 5.3%. Recommended margins are 4 to 5 mm. SOR A
• Cryosurgery (4 studies, n = 796): Recurrence rate was 3.0% to 4.3%. Cumulative 5-year rate (3 studies) ranged from 0% to 16.5%.6 SOR A Recommended freeze times are 30 to 60 seconds with a 5-mm halo. This can be divided up into two 30-second freezes with a thaw in between. For such long freeze times, most patients will prefer a local anesthetic (Figure 170-23). SOR C
• Curettage and desiccation (6 studies, n = 4212): Recurrence rate ranged from 4.3% to 18.1%; cumulative 5-year rate ranged from 5.7% to 18.8%. Three cycles of curettage and desiccation can produce higher cure rates than one cycle (Figure 170-24).6 SOR A
• Imiquimod is FDA approved for the treatment of superficial BCCs less than 2 cm in diameter.7 SOR B Confirm diagnosis with biopsy and use when surgical methods are contraindicated. A recent study combining cryotherapy with imiquimod improved decreased the recurrence rate.8
• Vismodegib is an FDA-approved targeted chemotherapy for the treatment of metastatic or nonresectable BCCs that cannot be treated with radiation. It targets the smoothened pathway, which is damaged in basal cell nevus syndrome and altered in most BCCs.9 SOR B

• All skin cancer prevention starts with sun protection.
• Unfortunately there is no proof that sunscreen use prevents BCC.10
• Sun protection should include sun avoidance, especially during peak hours of UV transmission, and protective clothing.
• United States Preventive Services Task Force has not found sufficient evidence to recommend regular screening for any skin cancer in the general population.11
• Most experts believe that persons at high risk for BCC (including previous personal history of BCC, high risk family history, and high risk skin types with significant sun exposure) should be screened regularly for skin cancer by a physician trained in such screening.
• Evidence for the value of self-screening is lacking but persons at high risk for skin cancer should also be encouraged to observe their own skin and to come in for evaluation if they see any suspicious changes or growths.

The prognosis for basal cell carcinoma is generally excellent with high cure rates with surgery and destructive modalities.  Large lesions on the face or lesions that have spread to sites deep to the skin have a poorer prognosis.

Patients should be seen at least yearly after the diagnosis and treatment of a BCC. The 3-year risk of BCC recurrence after having a single BCC is 44%.12

Patients should practice skin cancer prevention by sun-protective behaviors such as avoiding peak sun, covering up, and using sunscreen.

Patient Resources

• The Skin Cancer Foundation— http://www.skincancer.org/skin-cancer-information/basal-cell-carcinoma
• http://www.nlm.nih.gov/medlineplus/ency/article/000824.htm
• http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001827/

Provider Resources

• http://emedicine.medscape.com/article/276624-overview

Chapters and videos on diagnosing and surgically managing melanoma can be found in the following book/DVD or electronic application:

• Usatine R, Pfenninger J, Stulberg D, Small R. Dermatologic and Cosmetic Procedures in Office Practice. Philadelphia, PA: Elsevier, Inc.; 2012.
• Information about smartphone and tablet apps of this resource can be viewed at: www.usatinemedia.com