By Dr. Lori DeBlasi
Skin cancer can develop anywhere on the body, including the ankles and feet. Most skin cancers are painless. Often, there is a history of recurrent cracking, bleeding, or ulceration. On the parts of the body that receive the most sun exposure, the ultraviolet radiotion from the sun is the primary cause of skin cancer. Chronic, long-term sun exposure results in genetic changes in skin cells.
Skin cancers of the feet, however, are more often related to:
Viruses: Three human viruses are associated with skin cancer: human papilloma virus (HPV), Kaposi’s sarcoma (KS)-associated herpesvirus and human T-cell leukemia virus type 1.
Exposure to chemicals: Chemicals linked to skin cancer formation include arsenic, industrial tar, coal, paraffin, and certain types of oil.
Chronic inflammation and irritation: Inflammation from chronic skin injury can trigger cancer-causing mutations in the skin cells.
Inherited traits: About 5-10% of melanoma cases are inherited.
Unfortunately, the skin of the feet is often overlooked during routine medical examinations, and for this reason, it important that the feet are checked regularly for abnormalities that might indicate evolving skin cancer.
Types and Symptoms
Basal Cell Carcinoma: Basal cell carcinoma is considered to be one of the least aggressive cancers. It is frequently seen on sun-exposed skin surfaces. It does not occur often on the feet since your feet get less exposure to the sun. However, living in Southwest Florida, feet are exposed to the sun more since we are at the beach or wearing sandlas/flipflops more regularly than other parts of the US. When they do occur on the feet, they resemble non-cancerous growths. They will look like pearly white bumps or patches of bumps. They can ooze or crust over like an open sore.
Squamous Cell Carcinoma: Squamous cell carcinoma is the most common form of cancer on the skin of the feet. Most early types of squamous cell carcinoma stay in the skin and do not spread. When squamous cell cancer gets more advanced, it can become more aggressive and spread throughout the
the body. On the feet, squamous cell cancer may look like a scaly bump or plaque. A skin plaque is an elevated, solid, superficial lesion that is typically more than 1 centimeter in diameter. It may look a lot like a plantar wart, a fungal infection, callus, eczema, an ulcer, or other common skin conditions of the foot. Sometimes it can crack and bleed. It is usually painless but may be itchy.
Actinic keratosis (also known as solar keratosis or senile keratosis) is a pre-cancerous lesion. These lesions can lead to in situ squamous cell carcinoma or invasive squamous cell carcinoma. Actinic keratosis appears as rough, sandpaper-like, inconspicuous spots. Often, they are recognized by touch rather than sight if they are small. They are flat or slightly raised. Their color ranges from tan, pink or flesh toned. The spots then develop into scaly plaques with a base that has a distinctive reddish color.
Malignant Melanoma: Melanoma is a form of skin cancer that begins in the melanocytes, skin cells that control the pigment in your skin. It is one of the deadliest skin cancers because of its ability to grow into the deeper layers of the skin. By growing down into the skin, it can reach the blood vessels or lymph system allowing it to spread to other body organs. People of all races and colors get melanoma on their feet. The same number of African Americans and Caucasians develop melanoma on a foot. For people of African or Asian ethnicity, the feet and hands are the most common places for melanoma to appear.
It is extremely important to recognize melanoma early to ensure patient survival. Melanomas may occur on the skin on both the top and bottoms of the feet. Occasionally, melanoma may appear beneath a toenail. Under the nail it can begin as a dark vertical line or lines underneath a nail.
Melanomas may resemble benign moles, blood blisters, ingrown nails, plantar warts, ulcers caused by poor circulation, foreign bodies, or bruises. Upon close inspection, melanoma lesions will usually demonstrate asymmetry, irregular borders, alterations in color, and/or a diameter greater than 6 mm.
When to Visit a Podiatrist
Podiatrists are uniquely trained as lower extremity specialists to recognize and treat abnormal conditions on the skin of the lower legs and feet. Skin cancers affecting the feet may have a very different appearance from those arising on the rest of the body. For this reason, a podiatrist’s knowledge and clinical training is of extreme importance for patients for the early detection of both benign and malignant skin tumors.
Prevention
Prevention of skin cancer on the feet and ankles is similar to any other body part. Limit sun exposure, and make sure to apply appropriate sunscreen when you are outdoors, and your feet and ankles are exposed.
You can reduce your risk for this disease by:
• Inspecting your feet, toes and between the toes every day. Call us if you notice anything unusual. Know the warning signs of moles that may be cancerous: irregular borders, multi-colored, asymmetrical and diameter of larger than the end of a pencil eraser. Any mole on your foot that is changing—getting larger, crusting over or bleeding, etc. is cause for an examination
• Applying a water-resistant, broad-spectrum sunscreen with SPF of at least 30 that protects against UVA and UVB rays when outdoors. Don’t forget your feet and ankles. Reapply frequently, especially if you are sweating or swimming.
• Staying out of the sun when it is strongest, usually between 10 am and 4 pm. If you must be outside, keep feet covered or seek shade as much as possible.
• Wearing UV-absorbent sunglasses and a hat with a wide brim for more protection.
• Never use tanning beds! These increase your risk of melanoma dramatically.
Dr. Lori DeBlasi is certified by the American Board of Foot and Ankle Surgery®. Dr. DeBlasi works at Family Foot & Leg Center at the Colonial Blvd. and Estero offices. She is accepting new patients.
To make an appointment, call 239-430-3668 or visit www.NaplesPodiatrist.com.
Disclaimer: This content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health care provider with any questions you may have regarding a medical condition.