Melanoma is one of the common forms of skin cancer, and by far the deadliest because it is the most likely to metastasize. Melanoma is responsible for 6 of every 7 deaths from skin cancer in the United States even though it accounts for fewer new cases annually than the other forms—basal cell carcinoma and squamous cell carcinoma:

• Basal cell carcinoma (BCC) develops in more than one million persons annually in the U.S.
• Squamous cell carcinoma (SCC) develops in more than 200,000 persons annually in the U.S.
• Melanoma develops in 50,000 or more persons annually in the U.S.

Although melanoma is more likely to have a fatal outcome, SCC is capable of metastasizing. BCC is rarely capable of metastasizing. Surgical excision of all types of skin cancer may result in disfigurement. Any suspicious lesion should be examined by a dermatologist.

Basal Cell Carcinoma

Basal cell carcinoma (BCC) arises within the basal layer of the epidermis. Although it very seldom metastasizes, it is capable of metastasizing if the tumor invades lymph or blood vessels that can carry tumor cells to distant parts of the body. BCC spreads most often by local invasion of surrounding tissue. If left untreated, it can become large and disfiguring and destroy vital structures.

The major risk factors for BCC are:

• a personal or family history of BCC,
• history of sun exposure,
• a fair, white skin and blond or red hair and
• a tendency to burn before tanning.
• Ionizing radiation is also a major risk factor for BCC, 15-20 years after treatment.

BCC develops most frequently in skin chronically exposed to the sun—face, scalp, ears, neck, shoulders, hands, and back—but can and does occur in sun protected sites.

Characteristics of BCC lesions:

• A small, pearly, papule or nodule that increases slowly in size; some may be pigmented and resemble melanoma; most have a network of small blood vessels on the surface when visualized using surface microscopy.
• A solitary, flat or slightly depressed lesion that feels hard to the touch; some may be whitish to yellowish and have indistinct borders.
• One or more reddish, scaling plaques that slowly enlarge; some may resemble eczema or psoriasis.

A small, pearly, waxy nodule diagnosed as basal cell carcinoma.

A pigmented basal cell carcinoma superficially resembles a melanoma.

A pigmented basal cell carcinoma superficially resembles a melanoma. See next photo.

The previous lesion viewed by dermatoscopy reveals no characteristics of melanoma. Basal cell carcinoma was confirmed by biopsy.

(Photos used with permission of the American Academy of Dermatology National Library of Dermatologic Teaching Slides and the Sulzberger Institute for Dermatologic Education)

Early treatment of BCC by a dermatologist has a cure rate of more than 95%. Techniques of early treatment include surgical excision, Mohs microsurgery, cryosurgery (applying liquid nitrogen to the lesion), topical chemotherapy, electrodessication and curettage, and laser surgery. Early treatment can usually be carried out in an office or outpatient setting.

Squamous Cell Carcinoma

Squamous cell carcinoma (SCC) develops in the outer layers of skin. It is capable of metastasizing to other areas of the body if not treated early. It also spreads locally and may cause significant disfigurement.

The major risk factors for SCC are:

• a personal or family history of SCC;
• excessive, chronic exposure to sunlight over many years;
• overexposure or chronic exposure to x-rays (ionizing radiation used for treatment of another disease);
• long-term treatment with immunosuppressive drugs;
• pale white skin, especially with red or blond hair; and,
• tendency to burn before tanning.

SCC can also occur on sun-protected skin of white-skinned or dark-skinned people, at sites of scarring, skin disease, chemical or thermal burns, chronic skin ulcers, or sinus tracts.

Common characteristics of SCC lesions:

• A persistently non-healing, ulcerated nodule on the skin or lower lip; margins may be poorly defined.
• A wart-like growth or plaque.
• Lesions called actinic keratoses may appear as scaling pink plaques, inflamed plaques, or hard fibrous horn-like growths; these can be early beginnings of squamous cell carcinoma (Link to ActinicKeratosesNet).

A slightly tender lesion developed on the scalp of a 69-year-old man over a 6-month period. Biopsy confirmed the lesion as squamous cell carcinoma.

An unhealing sore persisted on the lower lip of a 67-year-old man. Biopsy confirmed the lesion as squamous cell carcinoma.

A wart-like growth developed near the ear of an elderly white man. Biopsy confirmed the lesion as squamous cell carcinoma.

Numerous crusted lesions developed on the hand of a middle-aged white man. The lesions were diagnosed as actinic keratoses, a premalignant lesion that can undergo malignant transformation into squamous cell carcinoma.

(Photos used with permission of the American Academy of Dermatology National Library of Dermatologic Teaching Slides and the Sulzberger Institute for Dermatologic Education)

Early treatment of SCC is usually curative. Early treatment of actinic keratoses removes unsightly lesions and prevents the possibility of malignant transformation. Treatment options for SCC are similar to those for basal cell carcinoma discussed earlier. One-third to two-thirds of actinic keratoses disappear spontaneously within 12 months of observation.

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