Skin cancer

We often view the sun's harmful rays as the primary cause of skin cancer, due to the fact that it is often found on parts of the body that receive the most sun exposure. While this may be true of some bodily skin cancers, this does not hold true for those that arise on the skin of the feet. Skin cancers of the feet are more often related to viruses, exposure to chemicals, chronic inflammation or irritation, or inherited traits. Unfortunately, the skin of the feet is often overlooked during routine medical examinations, and for this reason, it is important that the feet are checked regularly for abnormalities which might be indicative of evolving skin cancer.

Common types of skin cancers of the feet

Skin cancers of the feet have several features in common. Most are painless, and often there is a history of recurrent cracking, bleeding or ulceration. Frequently individuals discover their skin cancer after unrelated ailments near the affected site. Some of the most common cancers of the lower extremity are:

basil cell carcinomaBasal Cell Carcinoma frequently is seen on sun-exposed skin surfaces. With feet being significantly less exposed to the sun, it occurs there less often. This form of skin cancer is one of the least aggressive cancers in the body. It will cause local damage, but only rarely spreads beyond the skin. Basal cell cancers may appear as pearly white bumps or patches which may ooze or crust similar in appearance to an open sore. On the skin of the lower legs and feet, basal cell cancers often resemble non-cancerous skin tumors or benign ulcers.

squamous cell carcinomaSquamous Cell Carcinoma is the most common form of cancer on the skin of the feet. Most types of early squamous cell carcinoma are confined to the skin and do not spread. However, when advanced, some can become more aggressive and spread throughout the body. This form of cancer often begins as a small scaly bump or plaque, which may appear inflamed. Sometimes there is a history of recurrent cracking or bleeding. Occasionally they begin as a hard projecting callus-like lesion. Though squamous cell carcinoma is painless, it may be itchy. Squamous cell cancer may resemble a plantar wart, a fungal infection, eczema, an ulcer, or other common dermatological conditions of the foot.

malignant melanomaMalignant Melanoma is one of the deadliest skin cancers known. Nonsurgical treatments are rarely effective and many remain experimental. This type of skin cancer must be detected very early to ensure patient survival. Melanomas may occur on the skin of the feet and on occasion beneath a toenail. They are found both on the soles and on the tops of the feet. As a melanoma grows and extends deeper into the skin, it becomes more serious and may spread through the body through the lymphatics and blood vessels.

Malignant melamona has many potential appearances, leading to its nickname, "The Great Masquerader." This skin cancer commonly begins as a small brown-black spot or bump; however, roughly one third of cases will lack brown pigment and thus appear pink or red. These tumors may resemble common moles; however, close inspection will usually demonstrate asymmetry, irregular borders, alterations in color and/or a diameter of greater than 6mm. Melanomas may resemble benign moles, blood blisters, ingrown nails, plantar warts, ulcers caused by poor circulation, foreign bodies, or bruises.

learn the abcds of melanoma

Here are some common attriutes of cancerous lesions:

  • Asymmetry - if divided in half, the sides don't match.

  • Borders - They look scalloped, uneven, or ragged.

  • Color - They may have more than one color. These colors may have an uneven distribution.

  • Diameter - They can appear wider than a pencil eraser (greater than 6mm).

For other types of skin cancer, look for spontaneous ulcers and non-healing sores, bumps that crack or bleed, nodules with rolled of "donut-shaped" edges, or discrete scaly areas.

If you notice a mole, bump, or patch on the skin of a friend or family member that meets any of these criteria, encourage them to see an APMA member podiatrist immediately. To find one in your area, visit www.apma.org.

The role of today's podiatrist in the detection and management of skin disease

Podiatrists are uniquely trained as lower extremity specialists to recognize and treat abnormal conditions as they present themselves on the skin of the lower legs and feet. Skin cancers in the lower extremity 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.

Your podiatrist will investigate the possibility of skin cancer both through his/her clinical examination and with the use of a skin biopsy. A skin biopsy is a simple procedure in which a small sample of the skin lesion is obtained and sent to a specialized laboratory where a skin pathologist will examine the tissue in greater detail. To ensure that you receive the very best in care, your podiatrist will likely require that your skin biopsy be sent to a lab with board-certified dermatopathologists who have specialized training in the analysis of abnormal skin lesions from the lower leg and foot. If a lession is determined to be malignant, your podiatrist will recommend the best course of treatment for your condition.

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