Skin cancer is the most common type of cancer in the United States. Each year, more than 68,000 Americans are diagnosed with melanoma, and another 48,000 are diagnosed with an early form of the disease that involves only the top layer of skin. Also, more than 2 million people are treated for basal cell or squamous cell skin cancer each year.

If you have a change on your skin, your doctor must find out whether or not the problem is from cancer. You may need to see a dermatologist, a doctor who has special training in the diagnosis and treatment of skin problems. Your doctor will check the skin all over your body to see if other unusual growths are present.



Melanoma is caused by changes in skin cells called melanocytes. These cells make a skin color pigment called melanin. Melanin is responsible for skin and hair color.

Melanoma can appear on normal skin. Or, it can begin as a mole or other area that then changes in appearance. Some moles that are present at birth may develop into melanomas.

Larger moles that are present at birth are at higher risk of developing melanoma.

There are four major types of melanoma:

  • Superficial spreading melanoma is the most common type. It is usually flat and irregular in shape and color, with different shades of black and brown. It is most common in Caucasians.
  • Nodular melanoma usually starts as a raised area that is dark blackish-blue or bluish-red. Some do not have any color (amelanotic melanoma).
  • Lentigo maligna melanoma usually occurs in older people. It is most common in sun-damaged skin on the face, neck, and arms. The abnormal skin areas are usually large, flat, and tan with areas of brown.
  • Acral lentiginous melanoma is the least common form. It usually occurs on the palms, soles, or under the nails. It is more common in African Americans.

Melanoma is not as common as other types of skin cancer, such as basal cell carcinoma. But more and more people are developing melanoma, especially young adults.


Risk Factors for Melanoma:

The risk of developing melanoma increases with age, though the risk is rising in young people.

You are more likely to develop melanoma if you:

  • Have fair skin, blue or green eyes, or red or blond hair
  • Live in sunny climates or at high altitudes
  • Spent a lot of time in high levels of strong sunlight because of a job or other activities
  • Have had one or more blistering sunburns during childhood
  • Use tanning devices
  • Having close relatives with melanoma
  • Certain types of moles (atypical or dysplastic) or many birthmarks
  • Weakened immune system due to disease or medicines


Signs/Symptoms of melanoma:

A mole, sore, lump, or growth on the skin can be a sign of melanoma or other skin cancer. A sore or growth that bleeds, or changes in color can also be a sign of skin cancer.


The ABCDE system can help you remember possible symptoms of melanoma:

  • Asymmetry: one half of the mole does not match the other half
  • Border: the border or edges of the mole are ragged, blurred, or smudgy
  • Color: the mole has different colors, or the color is changing (getting darker or areas of the mole losing color) over time
  • Diameter: the diameter of the mole is larger than the diameter of a pencil
  • Evolving: the mole looks different from others and/or is changing in size, color or shape


Squamous Cell Carcinoma

Squamous cell skin cancer affects the epidermis, the top layer of your skin.

Squamous cell cancer may occur in undamaged skin. It can also occur in skin that has been injured or inflamed. Most squamous cell cancers occur on skin that is regularly exposed to sunlight or other ultraviolet radiation.

The earliest form of squamous cell cancer is called Bowen disease (or squamous cell carcinoma in situ). This type does not spread to nearby tissues, because it is still in the outermost layer of the skin.

Actinic keratosis is a precancerous skin lesion that may become a squamous cell cancer.

A keratoacanthoma is a mild type of squamous cell cancer that grows rapidly.


Risk Factors:

Risks of squamous cell cancer include:

  • Having light-colored skin, blue or green eyes, or blond or red hair
  • Long-term, daily sun exposure (such as in people who work outside)
  • Many severe sunburns early in life
  • Older age
  • Having had many x-rays
  • Chemical exposure
  • A weakened immune system, especially in persons who have had an organ transplant.


Signs/ Symptoms of Squamous Cell Carcinoma

Squamous cell cancer usually occurs on the face, ears, neck, hands, or arms. It may occur on other areas.

The main symptom is a growing bump that may have a rough, scaly surface and flat reddish patches.

The earliest form (squamous cell carcinoma in situ) can appear as a scaly, crusted, and large reddish patch that can be larger than 1 inch (2.5 centimeters).

A sore that does not heal can be a sign of squamous cell cancer. Any change in an existing wart, mole, or other skin lesion could be a sign of skin cancer.


Basal Cell Carcinoma

Basal cell cancer is the most common form of cancer in the United States. Most skin cancers are basal cell cancer.

Basal cell cancers occur in the bottom layer of the skin, called the basal cell layer. Most basal cell cancers occur on skin that is regularly exposed to sunlight or other ultraviolet radiation.

Basal cell cancer is almost always slow-growing. It rarely spreads to other parts of the body.


Risk Factors:

You are more likely to develop basal cell cancer if you:

  • Have light-colored or freckled skin
  • Have blue, green, or grey eyes
  • Have blond or red hair
  • Have overexposure to x-rays or other forms of radiation
  • Have many moles
  • Have close relatives who have or had skin cancer
  • Had many severe sunburns early in life
  • Long-term daily sun exposure (such as the sun exposure received by people who work outside)
  • Smoking
  • Weakened immune system, such as being on medicines that suppress the immune system after an organ transplant
  • Inherited skin diseases, such as nevoid basal cell carcinoma syndrome
  • Have had photodynamic therapy


Signs/Symptoms of Basal Cell Cancer:

Basal cell cancer usually grows slowly and is often painless. It may not look that different from your normal skin. You may have a skin bump or growth that is:

  • Pearly or waxy
  • White or light pink
  • Flesh-colored or brown
  • A red, scaly patch of skin

In some cases, the skin is just slightly raised, or even flat.

You may have:

  • A skin sore that bleeds easily
  • A sore that does not heal
  • Oozing or crusting spots in a sore
  • A scar-like sore without having injured the area
  • Irregular blood vessels in or around the spot
  • A sore with a depressed (sunken) area in the middle




National cancer institute