How Malignant Melanoma Affects the Feet

Malignant melanoma is a serious form of skin cancer that can develop anywhere on the body, including the feet, toes, soles, and beneath the toenails. While melanoma is often associated with sun exposure, some types that affect the feet may appear in areas that receive little or no sunlight.

Because melanoma on the foot can be mistaken for a bruise, mole, wart, sore, or toenail problem, it is important to have any suspicious or changing spot evaluated promptly by a medical professional.

What Is Malignant Melanoma?

Malignant melanoma is a cancer that begins in melanocytes, the cells that give skin its color. When caught early, melanoma is often highly treatable. When it is found late, it can become life-threatening because it may spread to other areas of the body.

Although melanoma accounts for a small percentage of all skin cancers, it is responsible for a significant number of skin cancer deaths. Melanoma can occur on the feet, including the soles, toes, and toenails, where it may be harder to see during normal daily activities.

At Central Kansas Podiatry Associates, our Wichita nail and skin care podiatrist can evaluate suspicious spots, discoloration, and skin changes on the feet and help determine the next appropriate step.

What Does Melanoma on the Foot Look Like?

Melanoma on the foot may appear as a dark spot, an irregular mole, a streak beneath a toenail, or a sore that does not heal. It may be brown, black, blue-black, red, pink, tan, or a mixture of colors.

Warning signs may include:

• A spot that changes in size, color, shape, or texture
• An irregular or uneven border
• Multiple colors within one lesion
• A new dark spot on the sole of the foot
• A dark streak under a toenail
• A sore or lesion that bleeds, crusts, or does not heal
• A spot that looks different from other moles or marks on your skin

Some foot melanomas are painful, but many are not. Do not wait for pain before having a suspicious spot examined.

Types of Malignant Melanoma That Can Affect the Feet

Several types of melanoma can develop on the feet, toes, or beneath the toenails. Understanding the different forms of melanoma can help patients recognize suspicious changes and seek prompt evaluation.

Superficial Spreading Melanoma

Superficial spreading melanoma is the most common type of melanoma, accounting for approximately 70% of cases. It often develops in middle-aged adults and typically appears as a flat or slightly raised discolored patch with irregular borders and varying shades of brown, black, tan, red, or white.

Although it is more common on the trunk in men and the legs in women, it can also occur on the feet. When it appears on the lower extremities, it is often found on non-weight-bearing areas. This type of melanoma generally grows outward across the skin before penetrating deeper tissues.

Nodular Melanoma

Nodular melanoma accounts for approximately 15% to 20% of melanoma cases and is considered one of the more aggressive forms of skin cancer. It is most commonly diagnosed in adults over age 50, although it can occur at any age.

This type of melanoma often appears as a dark brown, black, blue-black, or sometimes pinkish-red raised bump. Unlike superficial spreading melanoma, nodular melanoma tends to grow vertically into deeper tissues relatively quickly. It may develop on the foot, ankle, or beneath a toenail and should be evaluated immediately if a new or changing lesion is noticed.

Lentigo Maligna Melanoma

Lentigo maligna melanoma accounts for approximately 5% to 10% of melanoma cases. It most commonly develops in older adults, particularly those over age 65, after years of cumulative sun exposure.

It typically begins as a flat, slowly enlarging patch of tan, brown, or black discoloration with irregular borders. While it is most frequently found on sun-exposed areas such as the face, ears, and neck, it can occasionally develop on the legs or feet. Lentigo maligna melanoma often grows slowly over many years before becoming invasive.

Acral Lentiginous Melanoma

Acral lentiginous melanoma is the type of melanoma most associated with the feet. Although it represents a small percentage of all melanoma cases overall, it is the most common form of melanoma found on the soles of the feet, palms of the hands, and beneath the nails.

This form of melanoma can affect people of any race or ethnicity and is not strongly associated with sun exposure. It may appear as a dark patch on the bottom of the foot, a streak beneath a toenail, or an area of discoloration that gradually enlarges over time.

Because acral lentiginous melanoma often develops in areas people do not inspect regularly, diagnosis may be delayed. Any unexplained dark spot, persistent discoloration, or changing lesion on the foot should be evaluated by a podiatrist or dermatologist.

How Does Melanoma Feel?

Melanoma may or may not cause pain. Some lesions itch, bleed, crust, or become tender, while others cause no symptoms at all.

Melanomas on the feet may become irritated by shoes, socks, or pressure from walking. However, the absence of pain does not mean a spot is harmless. Any changing or unusual mark on the foot should be checked.

How to Check for Melanoma on the Feet

When checking your feet for melanoma, use the ABCDE warning signs:

• A - Asymmetry: One half of the spot does not match the other half.
• B - Border: The edges are uneven, blurred, jagged, or irregular.
• C - Color: The spot has multiple colors or unusual coloring.
• D - Diameter: The spot is larger than 6 millimeters or continues to grow.
• E - Evolving: The spot changes in size, shape, color, height, or symptoms.

Be sure to check the tops and bottoms of your feet, between the toes, around the heels, and under or around the toenails. If you have diabetes, neuropathy, poor vision, or difficulty reaching your feet, ask a family member, caregiver, or podiatrist to help monitor your feet regularly.

If a spot looks suspicious or different from the others, schedule an evaluation. You can also review our information about when to see a podiatrist for foot and ankle concerns.

What Causes Melanoma?

Several factors may increase the risk of melanoma. Long-term ultraviolet light exposure is one known risk factor because UV light can damage the DNA in skin cells. A history of severe sunburns, especially earlier in life, may also increase risk.

Other risk factors may include:

• Fair skin that burns or freckles easily
• Blonde or red hair
• Blue or light-colored eyes
• A personal or family history of melanoma
• A weakened immune system
• Older age
• A history of abnormal moles

However, melanoma on the foot is not always linked to sun exposure. Some melanomas, especially acral lentiginous melanoma, may develop on the soles of the feet or beneath the nails where sun exposure is limited.

What Should I Do If I Notice a Suspicious Spot?

If you notice a new, changing, bleeding, painful, or unusual spot on your foot, do not try to treat it at home. Do not assume it is a bruise, wart, callus, or toenail problem without having it evaluated.

You should contact a podiatrist or dermatologist if you notice:

• A dark spot on the sole of the foot
• A streak or discoloration under a toenail
• A sore that does not heal
• A mole that changes shape, size, or color
• A spot that bleeds, crusts, or becomes irritated
• A lesion that looks different from others on your skin

Some skin conditions on the feet, including plantar warts, calluses, wounds, and toenail conditions, can resemble more serious problems. A professional evaluation can help determine what is causing the change.

What Will My Doctor Do for Melanoma?

If your doctor suspects melanoma, a biopsy may be recommended. A biopsy removes a small sample of tissue so it can be examined and diagnosed.

If melanoma is confirmed, additional treatment will depend on the type, location, depth, and whether it has spread. Treatment may involve removal of the melanoma and additional testing. In some cases, imaging or lymph node testing may be recommended to determine whether the cancer has spread beyond the original site.

Because the feet have limited soft tissue and skin coverage, melanoma in this area can be more complicated to treat if diagnosis is delayed. Early evaluation is important.

How to Help Prevent Melanoma

While not every melanoma can be prevented, you can reduce risk and improve early detection by protecting your skin and checking your feet regularly.

Helpful prevention and monitoring steps include:

• Use sunscreen on exposed skin, including the tops of the feet when wearing sandals
• Avoid tanning beds
• Wear protective clothing and shoes when outdoors
• Inspect your feet, toes, and toenails regularly
• Watch for new or changing spots
• Schedule an evaluation for any suspicious lesion

Patients with diabetes, neuropathy, or a history of foot wounds should be especially careful about checking their feet. Learn more about diabetic foot wound prevention and the importance of monitoring changes in the skin.

Schedule an Appointment With Our Wichita Podiatrist

If you notice a suspicious spot, dark streak, changing lesion, or sore on your foot that does not heal, Central Kansas Podiatry Associates can help evaluate the problem and guide you toward the appropriate next step.

We provide care for many nail and skin conditions, including foot warts, calluses, toenail problems, wounds, and suspicious skin changes.

Call 316-269-3338 or request an appointment with our Wichita podiatrist today.

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