Most often, skin cancer on the arm is a basal cell or squamous cell cancer or melanoma. Basal and squamous cell skin cancers are common and highly curable. Melanoma is less common and more likely to spread, which makes it more dangerous.

Visual symptoms of skin cancer on the arm can vary but often include spots or moles of unusual sizes, shapes, and colors. Sometimes the areas can bleed or be painful or itchy.

While researchers have identified many risk factors for skin cancer, they are still working to understand how these factors cause cancer and find ways to prevent it.

This article outlines types of skin cancer on the arm and causes, risk factors, and prevention.

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Typically, skin cancer on the arm appears as a spot, mole, bump, or lesion that is unusual in size, color, or texture.

The keyword here is “unusual.” Not all spots that appear on the arm are cancerous. For example, small, even-toned, and flat spots are not unusual. They are common and typically harmless.

Spots or lesions that are large, varying in color, and raised or have an uneven texture are more likely to be skin cancer.

For people with darker skin tones, it may be easier to feel the spot or lesion on the arm than to see it.

Learn more about skin cancer in darker skin tones here.

Skin cancer may develop anywhere on the body, but some types usually develop on sun-exposed skin.

According to the American Cancer Society, the two most common types of skin cancer are basal cell carcinoma (BCC) and squamous cell carcinoma (SCC).

BCC and SCC

BCC, also called basal cell skin cancer, begins in the lower part of the epidermis. It usually develops on the most sun-exposed areas of skin. BCC is slow growing and typically does not spread to other body parts if treated in time.

SCC, also called squamous cell cancer, begins in the outer part of the epidermis.

Like BCC, SCC typically develops on areas of skin that get the most sun exposure. However, it can also form on:

  • chronic skin sores
  • scars on the skin in other areas
  • the skin of the genital area (less often)

BCC and SCC may have the following features:

  • scar-like flat, firm areas of skin
  • raised patches of skin that may itch
  • small, pearly bumps with areas of black, brown, or blue
  • growths with raised edges, lowered centers, and surrounded by abnormal-looking blood vessels
  • growths that look like warts
  • open sores that do not heal or heal and then return

Learn more about spotting BCC and SCC.

Melanoma

Melanoma is another type of skin cancer that can develop on the arm.

Melanoma begins in the melanocytes. Melanocytes are cells in the basal layer that typically make melanin, which produces skin pigmentation. Melanoma can develop anywhere on the skin where melanocytes begin growing out of control.

Typically, melanoma appears as an atypical mole. Brown moles, freckles, and other spots are common and often harmless.

While less common than BCC and SCC, melanoma is much more dangerous because it is more likely to spread to other body parts if it is not detected and treated early.

Read more about moles here.

Other types of skin cancer

The following types of skin cancer can develop on the arm but make up less than 1% of skin cancers:

Additionally, certain kinds of sarcoma may begin on or spread to the arm.

While anyone can develop skin cancer, some people have a greater risk.

This includes people who have:

Additionally, the risk of developing skin cancer increases with age. For example, the average age of diagnosis for melanoma is 65 years.

Currently, there is no sure way to prevent skin cancer. According to the National Cancer Institute, there are insufficient studies on how to lower the risk.

However, because most skin cancers start from ultraviolet radiation, skin experts recommend limiting sun exposure, especially on days with a high Ultraviolet (UV) Index.

People can limit sun exposure by:

  • avoiding the sun during peak hours, from 10 a.m. to 4 p.m. in the continental United States
  • wearing protective clothing, such as hats, sunglasses, and long sleeves
  • applying sunscreen with a sun protection factor (SPF) of at least 30
  • staying in shaded areas when outside
  • being mindful around water, sand, and snow due to their reflective properties

Furthermore, experts agree it is best to avoid indoor tanning entirely due to the higher cancer risk.

Anyone who notices the visual signs of skin cancer listed above should contact their physician or a dermatologist.

However, not all skin cancers appear the same. Because of this, a person can contact their doctor if they notice any unusual changes in the skin on their arm, including:

  • new spots
  • a mole that changes in size, shape, or color
  • a spot with redness or swelling spreading from its border
  • any spot that looks different from other spots on their body
  • an itchy, painful, or tender spot that will not heal or heals but comes back
  • a mole that begins oozing or bleeding, becomes scaly, or has the appearance of a bump or lump

A person should tell the doctor if they have any risk factors for skin cancer, such as a family history or a personal history of blistering sunburns.

BCC and SCC are highly curable, especially with early treatment.

Melanoma is also highly curable in the early stages. However, it is also more likely to spread to other body parts, affecting the outlook.

A relative survival rate helps show how long a person with a particular condition will live after receiving a diagnosis compared with people without the condition.

The 5-year relative survival rate for people with melanoma is:

  • Localized melanoma that has not spread: 99.5%
  • Regional melanoma that has spread to regional lymph nodes: 70.6%
  • Distant cancer that has spread to other regions: 31.9%

Regardless of the type of skin cancer on the arm, the earlier a person receives treatment, the better their outlook.

BCC, SCC, and melanoma are common skin cancers that can develop in sun-exposed areas, such as the arm. They may appear as unusual skin lesions that can differ in appearance depending on skin tone.

People can help prevent skin cancer by covering the skin, wearing sunscreen, and seeking shade.

A person’s outlook is generally good as long as the cancer does not spread and a person receives prompt treatment.