Skin Cancer Overview (cont.)
Norman Levine, MD
Dr. Norman Levine, MD, is a dermatologist in active practice in Tucson, Arizona. He has authored four books about skin health and dermatology therapy and contributed to hundreds of articles, several book chapters, and even a CD-ROM. Dr. Levine is a reviewer of dermatological cases for Physicians' Review Network.
John P. Cunha, DO, FACOEP
John P. Cunha, DO, is a U.S. board-certified Emergency Medicine Physician. Dr. Cunha's educational background includes a BS in Biology from Rutgers, the State University of New Jersey, and a DO from the Kansas City University of Medicine and Biosciences in Kansas City, MO. He completed residency training in Emergency Medicine at Newark Beth Israel Medical Center in Newark, New Jersey.
In this Article
- What is skin cancer?
- What are the risk factors for skin cancer?
- What causes skin cancer?
- What are the different types of skin cancer?
- What are the signs and symptoms of skin cancer?
- When is a mole dangerous or high-risk for becoming a skin cancer?
- What are the most common sites where skin cancer develops?
- How is skin cancer diagnosed?
- What is the staging for skin cancer?
- What is the treatment for skin cancer?
- What kinds of doctors treat skin cancer?
- What is the prognosis for skin cancer?
- Can skin cancer be prevented?
- Sunscreen use and vitamin D
- Skin Cancer Risks
- Take the Skin Cancer Quiz
- Sun-Damaged Skin Dangers
- Skin Cancer (Melanoma) FAQs
- Find a local Dermatologist in your town
What causes skin cancer?
The exact cause of skin cancer is unknown. It appears basal cell skin cancers arise from basaloid cells in the upper layer of the skin. Uncontrolled growth of these cells is regulated by other factors in the skin. When that regulation is lost, skin cancer cells begin to grow into tumors.
In squamous cell skin cancers, the tumors arise from a normal cell in the top layer of the skin, the epidermis. As with basal cell cancers, these cells are prevented from growing wildly by genetically controlled factors. When there is an alteration in the genes that regulate these cells, the control is lost and skin cancers start to grow. In many instances, the genes are altered by sunlight exposure.
What are the different types of skin cancer?
There are several different types of skin cancers:
- Basal cell carcinoma is the most common cancer in humans. Over 1 million new cases of basal cell carcinoma are diagnosed in the U.S. each year. There are several different types of basal cell carcinoma, including the superficial type, the least worrisome variety; the nodular type, the most common; and the morpheaform, the most challenging to treat because the tumors often grow into the surrounding tissue (infiltrate) without a well-defined border.
- Squamous cell carcinoma accounts for about 20% of all skin cancers but is more common in immunosuppressed people. In most instances, its biologic behavior is much like basal cell carcinoma, with minimal chance of spread. However, some of these tumors can act in an aggressive fashion and can even metastasize and cause death.
- Less common skin cancers include melanoma, Merkel cell carcinoma, atypical fibroxanthoma, cutaneous lymphoma, and dermatofibrosarcoma.
What are the signs and symptoms of skin cancer?
Most basal cell carcinomas have few if any signs or symptoms. Squamous cell carcinomas may be painful. Both forms of skin cancer may appear as a sore that bleeds, oozes, crusts, or otherwise will not heal. There is often a slowly growing bump on the skin that may bleed after minor trauma. Both kinds of skin cancers may have raised edges and a central ulceration.
Signs and symptoms of basal cell carcinomas include:
- Appearance of a shiny pink, red, pearly, or translucent bump
- Pink skin growths or lesions with raised borders that are crusted in the center
- Raised reddish patch of skin that may crust or itch, but is usually not painful
- A white, yellow, or waxy area with a poorly defined border that may resemble a scar
Signs and symptoms of squamous cell carcinomas include:
- Persistent, scaly red patches with irregular borders that may bleed easily
- Open sore that does not go away for weeks
- A raised growth with a rough surface that is indented in the middle
- A wart-like growth
Actinic keratoses (AK), also called solar keratosis are scaly, crusty lesions caused by damage from ultraviolet light, often in the facial area, scalp, and hands. In some cases these are considered potential precancers. If untreated, up to 10% of actinic keratosis growths can develop into squamous cell carcinoma, and in rare cases some can turn into basal cell carcinomas.
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