Slideshow: Precancerous Skin Lesions and Skin Cancer Pictures

The Warning Signs of Skin Cancer

Like many cancers, skin cancers—including melanoma, basal cell carcinoma, and squamous cell carcinoma—start as precancerous lesions. These precancerous lesions are changes in skin that are not cancer but could become cancer over time. An estimated 40% to 50% of fair-skinned people who live to be 65 will develop at least one skin cancer. Learn to spot the early warning signs. Skin cancer can be cured if it's found and treated early.

Actinic Keratosis (Solar Keratosis)

The small, scaly patches caused by too much sun exposure commonly occur on the head, neck, or hands, but can be found elsewhere. They're the early beginnings of skin cancer. Actinic keratosis usually appears on people after age 40, but they can show up in much younger people. Fair-skinned, blond, or red-haired people with blue or green eyes are most at risk. Early treatment is advised to stop progression to squamous cell skin cancer.

Actinic Cheilitis (Farmer's Lip)

Related to actinic keratosis, actinic cheilitis is a precancerous condition that usually appears on the lower lips. Scaly patches or persistent dryness and cracking of the lips may be present. Less common symptoms include swelling of the lip, loss of the sharp border between the lip and skin, and prominent lip lines. Actinic cheilitis may evolve into invasive squamous cell carcinoma if not treated.

Cutaneous Horns

The cutaneous horn appears as a funnel-shaped growth that extends from a red base on the skin. It is composed of compacted keratin (the same protein in nails). The size and shape of the growth can vary considerably, but most are a few millimeters in length. Squamous cell carcinoma is often found at the base. It usually occurs in fair-skinned elderly adults with a history of significant sun exposure.

Dysplastic Nevi (Atypical Moles)

Atypical moles are not cancer, but they can become cancer. They can be found in sun-exposed or sun-protected areas of the body. Atypical moles are larger (one-quarter inch across or larger) and more irregular in shape, with notched or fading borders. They may be flat or raised or the surface smooth or rough. They are typically of mixed color, including pink, red, tan, and brown.

Know Your ABCDEs

Most moles on a person's body look similar to one another. A mole or freckle that looks different from the others or that has a diameter larger than a pencil eraser or any characteristics of the ABCDEs of melanoma should be checked by a dermatologist. It could be cancerous. The ABCDEs are important characteristics to consider when examining your moles or other skin growths, so learn them in the slides to come.

Know Your ABCDEs: 'A' is for Asymmetry

Asymmetry means one half of a mole does not match the other half. Normal moles are symmetrical. When checking your moles or freckles, draw an imaginary line through the middle and compare the two halves. If they do not look the same on both sides, have it checked by a dermatologist.

Know Your ABCDEs: 'B' is for Border

If the border or edges of the mole are ragged, blurred, or irregular, have it checked by a dermatologist. Melanoma lesions often have uneven borders.

Know Your ABCDEs: 'C' is for Color

A mole that does not have the same color throughout or that has shades of tan, brown, black, blue, white, or red is suspicious. Normal moles are usually a single shade of color. A mole of many shades or that has lightened or darkened should be checked by a doctor.

Know Your ABCDEs: 'D' is for Diameter

A mole is suspicious if the diameter is larger than the eraser of a pencil. Benign moles are usually less than 6 millimeters in diameter.

Know Your ABCDEs: 'E' is for Elevation

If a portion of the mole appears elevated, or raised from the skin, have it looked at by a doctor. Melanoma lesions often grow in size or change in height rapidly. A mole that is evolving—shrinking, growing larger, changing color, begins to itch or bleed—should also be checked.

Tips for Screening Moles for Cancer

Examine your skin after a shower while skin is wet. A common location for melanoma in men is on the back, and in women, the lower leg. But check your entire body for moles or suspicious spots once a month. Start at your head and work your way down. Check the "hidden" areas: between fingers and toes, the groin, soles of the feet, the backs of the knees. Check your scalp and neck for moles. Use a handheld mirror or ask a family member to help you look at these areas. Be especially suspicious of a new mole. Take a photo of moles and date it to help you monitor them for change. Pay special attention to moles if you're a teen, pregnant, or going through menopause, times when your hormones may be surging.

How Are Moles Evaluated?

If you find a mole or spot that has any ABCDE's of melanoma -- or one that's tender, itching, oozing, scaly, doesn't heal or has redness or swelling beyond the mole -- see a doctor. Your doctor may want to remove a tissue sample from the mole and biopsy it. If found to be cancerous, the entire mole and a rim of normal skin around it will be removed and the wound stitched closed. Additional treatment may be needed.

A Primer on Skin Cancer

Malignant melanoma, especially in the later stages, is serious and treatment is difficult. Early diagnosis and treatment can increase the survival rate. Nonmelanoma skin cancers include basal cell carcinoma and squamous cell carcinoma. Both are common and are almost always cured when found early and treated. People who've had skin cancer once are at risk for getting it again; they should get a checkup at least once a year.

Melanoma

Melanoma is not as common as other types of skin cancer, but it's the most serious and potentially deadly. Possible signs of melanoma include a change in the appearance of a mole or pigmented area. Consult a doctor if a mole changes in size, shape, or color, has irregular edges, is more than one color, is asymmetrical, or itches, oozes, or bleeds.

Squamous Cell Carcinoma

This nonmelanoma skin cancer may appear as a firm red nodule, a scaly growth that bleeds or develops a crust, or a sore that doesn't heal. It most often occurs on the nose, forehead, ears, lower lip, hands, and other sun-exposed areas of the body. Squamous cell carcinoma is curable if caught and treated early. If the skin cancer becomes more advanced, treatment will depend on the stage of cancer.

Bowen Disease

Bowen disease is also called squamous cell carcinoma "in situ." It is a type of skin cancer that spreads outward on the surface of the skin. By contrast, "invasive" squamous cell carcinomas can grow inward and spread to the interior of the body. Bowen disease looks like scaly, reddish patches that may be crusted; it may be mistaken for rashes, eczema, fungus, or psoriasis.

Basal Cell Carcinoma

Basal cell carcinoma is the most common and easiest-to-treat skin cancer. Because basal cell carcinoma spreads slowly, it occurs mostly in adults. Basal cell tumors can take on many forms, including a pearly white or waxy bump, often with visible blood vessels, on the ears, neck, or face. Tumors can also appear as a flat, scaly, flesh-colored or brown patch on the back or chest, or more rarely, a white, waxy scar.

Less Common Skin Cancers

Uncommon types of skin cancer include Kaposi's sarcoma, mainly seen in people with weakened immune systems; Merkel cell carcinoma, which is usually found on sun-exposed areas on the head, neck, arms and legs but often spreads to other parts of the body; and sebaceous gland carcinoma, an aggressive cancer originating in the oil glands in the skin.

Who Gets Skin Cancer, and Why?

Sun exposure is the biggest cause of skin cancer. But it doesn't explain skin cancers that develop on skin not ordinarily exposed to sunlight. Exposure to environmental hazards, radiation treatment, and even heredity may play a role. Although anyone can get skin cancer, the risk is greatest for people who have:

• Fair skin or light-colored eyes
• An abundance of large and irregularly-shaped moles
• A family history of skin cancer
• A history of excessive sun exposure or blistering sunburns
• Lived at high altitudes or with year-round sunshine
• Received radiation treatments

Reduce Your Risk of Skin Cancer

Limit your exposure to the sun's ultraviolet rays, especially between 10 a.m. and 4 p.m., when the sun's rays are strongest. While outdoors, apply sunscreen liberally (don't forget the lips and ears!), wear a hat and sunglasses, and cover up with clothing. And remember, if you notice changes to your skin such as a new growth, a mole changing appearance, or a sore that won't heal, see a doctor right way.

More Reading on Skin Cancer

• Skin Cancer
• Skin Biopsy
• Sunburn
• Wilderness: Sunburn